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Polymorphism in macrocystis integrifolia bory in relation to water motion Pace, Danny Roy 1972

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PART I POLYMORPHISM I N MACROCYSTIS INTEGRIFOLIA BORY IN RELATION TO WATER MOTION PART I I CONTROL OF DIATOM CONTAMINATION IN FIELD CULTURE OF GAMETOPHYTIC AND EARLY SPOROPHYTIC PHASES IN THE LAMINARIALES by DANNY ROY PACE B.Sc. D a l h o u s i e U n i v e r s i t y , 1967 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n t h e Department o f Botany We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o t h e r e q u i r e d s t a n d a r d . The U n i v e r s i t y o f B r i t i s h Columbia March, .1972 In presenting this thesis in partial fulfilment of the requirements for an advanced, degree at the University of British Columbia, I agree that the Library shall make i t freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of Jot The University of British Columbia Vancouver 8, Canada Date /0/9/74 ABSTRACT A f i e l d s t u d y i n t h r e e p a r t s was u n d e r t a k e n t o i n v e s t i g a t e t h e r e l a t i o n s h i p s between t h e h a b i t o f M a c r o c y s t i s i n t e g r i f o l i a Bory and w a t e r movement. M o r p h o l o g i c a l v a r i a t i o n i n t i m e w i t h i n p o p u l a t i o n s was r e -l a t e d t o s e a s o n a l changes i n w i n d d i r e c t i o n and speed. Four s i t e s c o v e r i n g a w i d e range o f e x p o s u r e s , y e t c h a r a c t e r i z e d by e s s e n t i a l l y t h e same wat e r p r o p e r t i e s were sampled t h r o u g h o u t a p e r i o d o f one y e a r . I n t h i s way v a l i d c o m p a r i s o n s c o u l d a l s o be made between p o p u l a t i o n s . The s i t e s were a l l s i t u a t e d i n t h e v a c i n i t y o f Barn-f i e l d on t h e west c o a s t o f Vancouver I s l a n d , B.C. A s p o t s a m p l i n g s t u d y was u n d e r t a k e n t o d e t e r m i n e whether t h e t r e n d s e s t a b l i s h e d i n t h e above s t u d y a p p l y c o n s i s t e n t l y t h r o u g h o u t t h e range o f exposures c o v e r e d by M a c r o c y s t i s i n l o c -a l w a t e r s . Samples were o b t a i n e d from U c l u e l e t on Vancouver I s l a n d t o Warren I s l a n d i n s o u t h e r n A l a s k a . Through t h e s e s t u d i e s s e v e r a l a s p e c t s o f t h e h a b i t were found t o r e f l e c t t h e p r e v a i l i n g dynamic c o n d i t i o n s t o w h i c h t h e p l a n t had been s u b j e c t e d t h r o u g h o u t i t s development. A t r a n s p l a n t s t u d y was c a r r i e d o u t among t h e c o n t i n u o u s s a m p l i n g s i t e s t o e s t a b l i s h t h e mechanism o f r e s p o n s e t o dynamic c o n d i t i o n s . Growth d a t a o b t a i n e d t h r o u g h t h e t r a n s p l a n t s t u d y i n d i c a t e d t h a t s t i p e e l o n g a t i o n and b l a d e i n i t i a t i o n v a r y d i r e c t -l y w i t h w a t e r movement. Growth o f i n d i v i d u a l b l a d e s appears t o be independent o f t h i s f a c t o r . The r e s u l t s o f t h e t r a n s p l a n t s t u d y s u p p o r t e d by v a r i a t i o n s o b s e r v e d w i t h i n p l a n t s and w i t h i n p o p u l a t i o n s w i t h t i m e s t r o n g l y s u g g e s t t h a t t h e mechanism o f r e s p o n s e i s p h e n o t y p i c p l a s t i c i t y . However, p l a n t s o b s e r v e d on t h e o u t e r c o a s t were, i n some r e s p e c t s , m a r k e d l y d i s t i n c t . Thus t h e p o s s i b i l i t y o f a second mechanism o p e r a t i n g under c o n d i t i o n s o f g e n e t i c i s o l a t i o n ha not been d i s c o u n t e d . TABLE OF CONTENTS PART I Page ABSTRACT LIST OF TABLES LIST OF FIGURES ACKNOWLEDGMENTS INTRODUCTION 1 MATERIALS AND METHODS 6 CONTINUOUS SAMPLING STUDY D e s c r i p t i o n o f S i t e s 6 Q c e a n o q r a p h i c Data 8 Frond S a m p l i n g and Measurement 8 SPOT SAMPLING STUDY 10 TRANSPLANT STUDY Methods 11 D e s c r i p t i o n o f T r a n s p l a n t s 12 E v a l u a t i o n o f P l a n t Response 13 RESULTS 14 CONTINUOUS SAMPLING STUDY Changes Recorded i n Time and P l a c e 14 S t i p e D iameter 14 S t i p e L e n gth 16 D i s t a l M e r i s t e m a t i c R e g i o n 16 B l a d e s ; 17 Number i n R e l a t i o n t o S t i p e L e n g t h -17 W i d t h o f Mature Laminae . 17 Changes Recorded O n l y I n Space 19 SPOT SAMPLING STUDY 20 TRANSPLANT STUDY 21 Growth o f P r i m a r y Fronds 21 Growth o f Laminae 22 B l a d e s per U n i t L e ngth o f S t i p e 22 Lamina w i d t h 23 DISCUSSION 24 S t i p e Diameter 24 S t i p e L e n g t h 27 D i s t a l M e r i s t e m a t i c R e g i o n 27 B l a d e s Number i n R e l a t i o n t o S t i p e L e n g t h 30 Wi d t h o f Mature Laminae 30 Lamina T h i c k n e s s 33 S p i n e s . 34 Pneumatocysts 34 QUALITATIVE OBSERVATIONS 35 H o l d f a s t 35 S p o r o p h y l l s 36 THE ENTIRE PLANT 37 SUMMARY 38 FIGURES .. 41 TABLES 57 LITERATURE CITED 70 PART I I FOLLOWS PAGE 72 AND IS NUMBERED SEPARATELY LIST OF FIGURES FIGURE Page 1 Measurements of wind d i r e c t i o n and speed 41 (m.p.h.) taken throughout 1970 at Cape Beale atthe southeast entrance to Barkeley Sound 2a Coast of B r i t i s h Columbia and southern 42 Alaska showing s i t e s v i s i t e d throughout the spot sampling study. 2b Sites v i s i t e d throughout the continuous 43 sampling study. 3 Near-surface temperature/salinity diagrams 44 based on measurements taken at the four Bamfield s i t e s throughout August, 1970. 4 V a r i a t i o n with time of s a l i n i t y and tempera- 45 ture at f i v e meters i n Bamfield Inlet throughout 1969 - 70. 5 The Wizard I s l e t transplant s i t e following 46 the experiment. 6 V a r i a t i o n with time of mean sti p e diameter 47 and length at the four continuous sampling s i t e s throughout 1970. Maximum and minimum values are indicated be ho r i z o n t a l bars. 7 Recorded values of st i p e diameter and length 48 for fronds c o l l e c t e d throughout the continuous sampling study. A l i n e a r r e l a t i o n s h i p i s espressed g r a p h i c a l l y for three of the sampling s i t e s . 8 V a r i a t i o n with time of the mean number of 49 terminal s p l i t s on fronds c o l l e c t e d throughout the continuous sampling study. 9 Recorded v a l u e s o f b l a d e number and s t i p e 50 l e n g t h f o r f r o n d s c o l l e c t e d t h r o u g h o u t t h e c o n t i n u o u s s a m p l i n g s t u d y . A l i n e a r r e l a t i o n -s h i p i s e x p r e s s e d g r a p h i c a l l y f o r a l l s i t e s . 10 V a r i a t i o n w i t h t i m e o f t h e mean w i d t h o f young 51 mature l a m i n a e on f r o n d s c o l l e c t e d t h r o u g h o u t t h e c o n t i n u o u s s a m p l i n g s t u d y . 11 A b a d l y d e t e r i o r a t e d f r o n d extended toward t h e 52 s u r f a c e a t D i x o n I s l a n d . 12 T r a n s p l a n t s t u d y . Growth i n l e n g t h o f p r i m a r y 53,54 f r o n d s . 13 A d i s t a l m e r i s t e m a t i c r e g i o n o f a p l a n t from 55 W i z a r d I s l e t . 14 A d i s t a l m e r i s t e m a t i c r e g i o n o f a p l a n t from 55 Hope I s l a n d . 15,16,17 56 B a s a l p o r t i o n s o f l a m i n a e c o l l e c t e d d u r i n g t h e s a m p l i n g s t u d i e s . 18,19 M a r g i n s o f l a m i n a e from an exposed and a 56 m o d e r a t e l y exposed s i t e . LIST OF TABLES TABLE Page 1 Descriptions of s i t e s v i s i t e d throughout 57,58 the spot sampling and continuous sampling studies. 2 Analysis of variance among the four contin- 59 uous sampling s i t e s for width of young mature laminae. 3 Analysis of data obtained from sample blades 60,61 which were c o l l e c t e d i n the Bamfield region during A p r i l , May and June of 1970. 4 Measurements of fronds c o l l e c t e d throughout the 62,63 spot sampling study. 5 Measurements of blades obtained throughout the 64,65 spot sampling study. 6 Growth of primary fronds and i n i t i a t i o n rates 66 for laminae recorded throughout the transplant study. 7 Growth of laminae on plants involved i n the 67 transplant study. 8 Transplant study. V a r i a t i o n with time of the 68 mean number of blades per meter of s t i p e for primary fronds. 9 Transplant study. Maximum width, i n centimeters, 69 of mature laminae numbered from the base of the primary s t i p e . ACKNOWLEDGMENTS I w i s h t o e x p r e s s my a p p r e c i a t i o n t o t h e many p e r s o n s who a s s i s t e d me d u r i n g t h i s s t u d y . I n p a r t i c u l a r I am g r a t e f u l t o my s u p e r v i s o r , Dr. R. F. S c a g e l , f o r h i s un-f a i l i n g c o n f i d e n c e and f i n a n c i a l s u p p o r t . I am a l s o g r a t e -f u l t o my g r a d u a t e committee, w h i c h a l s o i n c l u d e d D r s . K. C o l e and R. Forman, f o r t h e i r a s s i s t a n c e and c r i t i c i s m o f t h e m a n u s c r i p t . S t a t i s t i c a l a n a l y s e s were c a r r i e d o u t under t h e gu i d a n c e o f Mr. S t e v e Borden. Mr. B r e n t o n B a i l l i e a s s i s t e d t h r o u g h o u t t h e f i e l d s t u d i e s . Mrs. H e l e n S t y a n a i d e d i n t h e c o l l e c t i o n o f f i e l d d a t a . Mr. C h a r l e s C o l l i n s o n a d v i s e d and a s s i s t e d i n t h e development o f t h e in_ s i t u c u l t u r e a p p a r a t u s . I am a l s o g r a t e f u l f o r t h e many c o n t r i b u t i o n s o f t h e f o l l o w i n g : D r s . L o u i s D r u e h l , Tony Chapman, J i m Markham, P e t e r Newroth and Mr. Ron Long. A s p e c i a l n o t e o f t h a n k s t o M i s s Gwyn K i b b l e and Judy Murphy f o r t h e i r a s s i s t a n c e i n t h e p r e p a r a t i o n o f t h e m a n u s c r i p t . -1-INTRODUCTION The p u r p o s e o f t h i s s t u d y was t o i n v e s t i g a t e t h e r e l a t i o n -s h i p s between polymorphism i n t h e s p o r o p h y t e o f M a c r o c y s t i s  i n t e q r i f o l i a Bory and v a r y i n g degrees o f w a t e r movement. Much a t t e n t i o n has been p a i d t o t h i s q u e s t i o n w i t h r e s p e c t t o t h o s e members o f t h e L a m i n a r i a l e s o t h e r t h a n t h e L e s s o n i a c e a e by s e v e r a l a u t h o r s i n c l u d i n g Burrows ( 1 9 5 8 ) , D r u e h l (1967), K a i n (1962, 1971), M a c F a r l a n e ( 1 9 6 1 ) , N o r t o n ( 1 9 6 9 ) , P a r k e (1948) and . Sundene (1958, 1961a, 1961b, 1964). From t h e s e works a g e n e r a l p a t t e r n has emerged w h i c h can b e s t be e x p l a i n e d by c o n s i d e r i n g a t y p i c a l l a m i n a r i a l e a n p l a n t c o n s i s t i n g o f a l a m i n a , s t i p e and h o l d f a s t . P r o c e e d i n g from a s h e l t e r e d l o c a l i t y t o one exposed t o t h e d i r e c t f o r c e o f t h e open s e a , t h e l a m i n a narrows and t h e t i s s u e s t h i c k e n , becoming tough y e t f l e x i b l e . The base o f t h e l a m i n a be-comes more c u n e a t e and i f t h e s p e c i e s i s c h a r a c t e r i z e d by t h e f o r m a t i o n o f l o n g i t u d i n a l s p l i t s t h e s e become more p r o m i n e n t , o f t e n b e i n g a b s e nt e n t i r e l y from p l a n t s o f t h e same s p e c i e s i n q u i e t e r w a t e r s . The l e n g t h o f t h e l a m i n a i s a h i g h l y v a r i a b l e f e a t u r e and i s d e t e r m i n e d by a l l o f t h e f a c t o r s w h i c h c o n t r i b u t e t o t e r m i n a l e r o s i o n as w e l l as growth r a t e and age. S t i p e s from exposed s i t e s a r e u s u a l l y l o n g e r and s m a l l e r i n d i a m e t e r but a r e a l s o s t r o n g e r and more f l e x i b l e . P a r k e (1948) t r e a t e d i n d e t a i l t h e s u b j e c t o f m o r p h o l o g i c a l v a r i a t i o n w i t h r e s p e c t t o t h e h o l d f a s t o f L a m i n a r i a s a c c h a r i n a ( L i n n a e u s ) Lamour. However, she a t t r i b u t e d t h e o c c u r r e n c e o f d i f f e r e n t forms t o t h e n a t u r e o f t h e s u b s t r a t u m r a t h e r t h a n e x-p o s u r e . She n o t e d t h a t p l a n t s g r o w i n g on s o l i d s u b s t r a t e s b o r e compact and t h i c k h o l d f a s t s w i t h s l i g h t l y b r a n c h e d h a p t e r a where-as p l a n t s g r o w i n g on s o f t s i l t had h o l d f a s t s w i t h t h i n , l o n g , c o p i o u s l y b r a nched h a p t e r a . However, o t h e r f e a t u r e s o f t h e p l a n t s -2-used as examples a l o n g w i t h t h e f a c t t h a t t u r b u l e n t w a t e r s s e l -dom l e n d t h e m s e l v e s t o t h e a c c u m u l a t i o n o f s i l t , s t r o n g l y s u g g e s t t h a t t h i s e f f e c t was more c l o s e l y r e l a t e d t o e x p o s u r e . Through t r a n s p l a n t s t u d i e s i t has been d e m o n s t r a t e d t h a t , g i v e n t h e p r o p e r s t i m u l u s , i n d i v i d u a l p l a n t s a r e c a p a b l e o f a s -suming a form a p p r o p r i a t e t o a p a r t i c u l a r s e t o f e n v i r o n m e n t a l c o n d i t i o n s . T h i s t y p e o f r e s p o n s e i s termed " p h e n o t y p i c p l a s ^ t i c i t y " . A l t h o u g h c e r t a i n a s p e c t s o f t h e t h a l l u s o f M a c r o c y s t i s can be compared d i r e c t l y w i t h t h e g e n e r a l i z e d l a m i n a r i a l e a n p l a n t d e s c r i b e d above, t h e r e a r e f e a t u r e s p e c u l i a r t o t h i s g rowth w h i c h s e t i t a p a r t and c r e a t e new o p p o r t u n i t i e s f o r m o r p h o l o g i c a l v a r -i a t i o n . The c o n t i n u o u s p r o d u c t i o n o f f r o n d s from t h e same h o l d -f a s t t h r o u g h o u t t h e y e a r p e r m i t s t h e p l a n t t o a d j u s t t o s e a s o n a l e n v i r o n m e n t a l changes. The p o t e n t i a l f o r a more immediate r e -sponse i s c r e a t e d by t h e c o n t i n u o u s p r o d u c t i o n o f new b l a d e s a t t h e apex o f t h e f r o n d . The e x t e n t o f w a t e r movement c a n v a r y s i g n i f i c a n t l y o v e r s h o r t p e r i o d s o f t i m e and w i t h d e p t h . T h i s c r e a t e s t h e p o s i b i l i t y f o r a w i d e v a r i a t i o n i n t h e form o f mature b l a d e s o c c u r r i n g on t h e same s t i p e . The i s o l a t i o n o f r e p r o d u c t -i v e and s o m a t i c r e g i o n s , w h i c h a l s o o c c u r s t o a l e s s e r e x t e n t i n t h e A l a r i a c e a e , e n a b l e s t h e p l a n t t o make t h e n e c e s s a r y morpho-l o g i c a l a d j u s t m e n t s t o t h e environment w i t h o u t i n t e r f e r r i n g w i t h i t s a b i l i t y t o r e p r o d u c e . There a r e o t h e r f e a t u r e s c h a r a c t e r i s t i c o f M a c r o c y s t i s w h i c h a r e n o t commonly found t h r o u g h o u t t h e o r d e r . These i n c l u d e t h e s p i n e s a l o n g t h e p e r i p h e r y o f t h e b l a d e s and t h e pneumatocysts a t t h e j u n c t i o n between b l a d e and s t i p e . M o r p h o l o g i c a l v a r i a t i o n i n M a c r o c y s t i s has l o n g been t h e sub-j e c t o f s p e c u l a t i o n . So v a r i a b l e a r e t h e form and d i m e n s i o n s o f t h e j u v e n i l e and mature b l a d e s , w i t h i n as w e l l as between p l a n t s , -3-t h a t Hooker (1847) d i s m i s s e d them as t a x o n o m i c a l l y u n i m p o r t a n t beyond t h e g e n e r i c l e v e l . Thus he c o n s i d e r e d t h e p r e v i o u s l y d e s c r i b e d s p e c i e s as synonyms o f M a c r o c y s t i s p y r i f e r a A g a r d h . He r e c o g n i z e d s i x v a r i e t i e s b u t p o i n t e d o u t t h a t t h e i r c h a r a c t e r -i s t i c s were i n f l u e n c e d c o n s i d e r a b l y by t h e r i g o u r s o f p r e s e r -v a t i o n and n a t u r a l c a u s e s such as e x p o s u r e . I n t h i s l a t t e r r e -s p e c t he r e l a t e d v a r i a t i o n i n t h e abundance o f s p i n e s , c o r r u g -a t i o n , t e x t u r e and b r e a d t h o f t h e l a m i n a e , d i m e n s i o n s o f t h e pneumatocysts and d i a m e t e r o f t h e s t i p e t o t h e d e g r e e o f w a t e r movement. S k o t t s b e r g (1907) o b s e r v e d a r e l a t i o n s h i p among c e r t a i n f e a t u r e s such as s p i n e s , pneumatocysts and e x p o s u r e . However, h i s c o n c l u s i o n s were l i m i t e d by t h e h i g h d e g r e e o f v a r i a t i o n w i t h i n l o c a l i t i e s . A r e l a t i o n s h i p between morphology and e x p o s u r e was f i r s t d e f i n e d f o r t h e o v e r a l l p l a n t by B r a n d t ( 1 9 2 3 ) . He d e s c r i b e d two extreme forms o f M a c r o c y s t i s p y r i f e r a ( L i n n a e u s ) C. Agardh as f o l l o w s : an exposed form c h a r a c t e r i z e d by v e r y s t o u t s t i p e s , l o n g , t a p e r i n g c y s t s w i t h t h i c k w a l l s and l o n g , narrow, t h i c k , tough b l a d e s ; and a s h e l t e r e d form c h a r a c t e r i z e d by s l e n d e r s t i p e s , n e a r l y g l o b u l a r , t h i n - w a l l e d c y s t s and b r o a d , t h i n , b r i t t l e b l a d e s w h i c h were more o r l e s s h e a r t - s h a p e d a t t h e b a s e . The c o l o u r a l s o v a r i e d , b e i n g much d a r k e r i n t h e exposed form. M a c r o c y s t i s i n t e q r i f o l i a Bory on t h e o t h e r hand d i d n o t show t h i s r a n g e o f forms a l t h o u g h from h i s d e s c r i p t i o n s i t appears t o have o c c u r r e d i n t h e same g e n e r a l l o c a l i t y . Womersley (1954) n o t e d t h e o c c u r r e n c e t h r o u g h o u t t h e genus o f a s i m i l a r r e l a t i o n s h i p w i t h r e s p e c t t o a number o f f e a t u r e s . These i n c l u d e d t h e s u r f a c e t e x t u r e ( r u g o s i t y ) o f t h e b l a d e s , t h e p r e s e n c e o r absence o f s p i n e s a l o n g t h e m a r g i n s , t h e demensions o f t h e pneumatocysts and t h e form o f t h e d i s t a l l a m i n a . -4-M a c r o c y s t i s has r e c e i v e d a g r e a t d e a l o f a t t e n t i o n o v e r much o f i t s g e o g r a p h i c r a n g e , due l a r g e l y t o i t s economic i m p o r t a n c e . S t u d i e s d e a l i n g s p e c i f i c a l l y w i t h t h e e f f e c t s o f ex p o s u r e on morphology have not been c a r r i e d o u t and t h e o b s e r v a t i o n s c i t e d above have not been t e s t e d q u a n t i t a t i v e l y . The p r e s e n t work was d i r e c t e d t oward t h e f o l l o w i n g b a s i c q u e s t i o n s : (1) How r e a d i l y does t h e morphology r e f l e c t s p a t i a l and tempor-a l changes i n e x p o s u r e ? Four s i t e s f o r r e g u l a r s a m p l i n g were s e l e c t e d i n c l o s e p r o x i m i t y t o one a n o t h e r so t h a t a l l would be c h a r a c t e r i z e d by e s s e n t i a l l y t h e same w a t e r p r o p e r t i e s e x c e p t e x-p o s u r e . T h i s t e c h n i q u e has a l r e a d y been s u c c e s s f u l l y a p p l i e d by N o r t o n ( 1 9 6 9 ) . (2) How c o n s i s t e n t l y do t h e f i n d i n g i n (1) a p p l y t h r o u g h o u t t h e range o f exposures c o v e r e d by M a c r o c y s t i s i n l o c a l w a t e r s ? Samples were o b t a i n e d from a v a r i e t y o f s i t e s c o v e r i n g a w i d e g e o g r a p h i c r a n g e . As t h e s e l o c a l i t i e s were e x p e c t e d t o v a r y w i t h r e s p e c t t o a v a r i e t y o f f a c t o r s t h e r e l a t i v e i m p o r t a n c e o f expos-u r e w o u l d be r e f l e c t e d i n t h e r e s u l t s . (3) What i s t h e g e n e t i c b a s i s o f m o r p h o l o g i c a l v a r i a t i o n i n t h e p l a n t ? A r e o n l y c e r t a i n v a r i e t i e s o r e c o t y p e s a b l e t o t h r i v e i n c e r t a i n h a b i t a t s o r a r e t h e f e a t u r e s under c o n s i d e r a t i o n t r u l y p l a s t i c ? A t r a n s p l a n t s t u d y w i t h i n t h e f o u r r e g u l a r s a m p l i n g s i t e s was c o n d u c t e d and c o r r e s p o n d i n g changes i n growt h r a t e and form were s t u d i e d . An at t e m p t was a l s o made t o c u l t u r e t h e p l a n t t h r o u g h t h e m i c r o s c o p i c phase o f i t s l i f e c y c l e under n a t u r a l c o n d i t i o n s . I t was hoped t h a t a c r o p o f young s p o r o p h y t e s o f known p a r e n t a g e o b t a i n e d i n t h i s manner would be a v a i l a b e f o r t r a n s p l a n t a t i o n . U n f o r t u n a t e l y t h e t e c h n i q u e was not d e v e l o p e d i n t i m e t o be o f use t o t h e p r e s e n t s t u d y . However, a c o m p l e t e d e s c r i p t i o n o f t h e t e c h n i q u e i s i n c l u d e d a t t h e end o f t h e t h e s i s -5-as a s e p a r a t e s e c t i o n . Based on r e s u l t s o f t h e above t h r e e s t u d i e s and t h o s e o f p r e v i o u s w o r k e r s , t h e f u n c t i o n a l s i g n i f i c a n c e o f m o r p h o l o g i c a l v a r i a t i o n i n t h i s s p e c i e s and t h e mechanism o f e n v i r o n m e n t a l c o n -t r o l a r e d i s c u s s e d . - 6 -MATERIALS AND METHODS CONTINUOUS SAMPLING STUDY Description of Sites The choice of s i t e s for continuous sampling was made main-l y on the basis of exposure to waves generated by p r e v a i l i n g winds. During the Spring and Summer months winds i n the Trevor Channel region of Barkeley Sound tend to blow most co n s i s t e n t l y from the south-east and west ( F i g . 1)» This creates wave forces t r a v e l l i n g up Trevor Channel, whereas during F a l l and Winter months surface waves are driven predominantly i n the opposite d i r e c t i o n . A more consistent, but gentler type of water movement, i s created by t i d a l currents. The flow i s hardly noticeable at s i t e s bordering Trevor Channel but i s amplified by narrow i n l e t s es-p e c i a l l y i f these empty into large basins. Such i s the case i n Bamfield I n l e t . Imbalances i n the t i d a l flow caused by the pro-jec t i o n of the Deer group of islands into Barkeley Sound are sus-pected as being responsible for the strong currents associated with many of the channels i n that region. With the highly i r r e g u l a r shore-line c h a r a c t e r i s t i c of the Bamfield area i t was possible to choose four s i t e s d i f f e r i n g widely i n exposure to water motion, yet l y i n g within a radius of only 0.9 n a u t i c a l miles. The four s i t e s shown i n Figure 2(b) are described as follows:-Wizard I s l e t -moderately exposed throughout a l l months of the year. Sub-ject to deflected waves o f f Helby Island during Spring and Summer and s l i g h t l y protected from the f u l l force of waves t r a v e l l i n g down Trevor Channel by a s e r i e s of p a r t i a l l y submerged peaks. - s u b j e c t t o moderate t i d a l c u r r e n t s . - s u b s t r a t e : s o l i d bed-rock g i v i n g way s l i g h t l y beyond t h e k e l p zone t o sand and b r o k e n s h e l l w i t h o c c a s i o n a l bedrock o u t c r o p p i n g s . - s l o p e : about 20-30 degrees a t t h e c o l l e c t i n g s i t e . S c o t t ' s Bay* - m o d e r a t e l y s h e l t e r e d t h r o u g h o u t a l l months o f t h e y e a r . S u b j e c t o n l y t o d e f l e c t e d waves e x c e p t f o r t h o s e t r a v e l l i n g f rom a n o r t h e r l y d i r e c t i o n , -not s u b j e c t t o n o t i c e a b l e t i d a l c u r r e n t s , - s u b s t r a t e : s o l i d b ed-rock g i v i n g way t o sand and b r o k e n r o c k a t about -10 f e e t . - s l o p e : about 10 d e g r e e s . B a m f i e l d I n l e t - s h e l t e r e d t h r o u g h o u t a l l months o f t h e y e a r . S u b j e c t o n l y t o d e f l e c t e d waves e x c e p t f o r t h o s e t r a v e l l i n g from a n o r t h e r l y d i r e c t i o n . - s u b j e c t t o s t r o n g t i d a l c u r r e n t s f l o w i n g a l o n g B a m f i e l d I n -l e t . - s u b s t r a t e : s o l i d and b r o k e n b e d - r o c k g i v i n g way a t about 15 f e e t t o s i l t . O c c a s i o n a l p l a n t s e x t e n d i n g i n t o t h i s zone on s c a t t e r e d r e f u s e . - s l o p e : about 20-40 d e g r e e s . D i x o n I s l a n d - s h e l t e r e d t h r o u g h o u t S p r i n g and Summer. M o d e r a t e l y exposed d u r i n g F a l l and W i n t e r months, b e i n g s u b j e c t t o o n l y s l i g h t l y d e f l e c t e d waves t r a v e l l i n g down T r e v o r C h a n n e l . T h i s r e s u l t s i n a c r o p p i n g back o f t h e o u t e r l i m i t s o f t h e k e l p bed d u r i n g t h e s e s e a s o n s . -not s u b j e c t t o n o t i c e a b l e t i d a l c u r r e n t s . - s u b s t r a t e : c o b b l e and l o o s e r o c k g i v i n g way t o sand w i t h s c a t t e r e d s t o n e and s h e l l a t about 15 f e e t . - s l o p e : about 10 d e g r e e s . * After Mr. R. Bruce Scott, a former resident of Bamfield and l o c a l h i s t o r i a n . Data on p o s i t i o n , open a n g l e ( t o o n s h o r e waves) and max-imum and minimum f e t c h a r e p r e s e n t e d f o r t h e above l o c a l i t i e s i n T a b l e 1. O c e a n o g r a p h i c Data T h i s s t u d y was based on t h e a s s u m p t i o n t h a t a l l f o u r s i t e s were s u b j e c t e d t o t h e same w a t e r mass such t h a t d i f f e r e n c e s be-tween s i t e s w ould n o t be s i g n i f i c a n t . I n o r d e r t o t e s t t h i s c o n -t e n t i o n n e a r - s u r f a c e t e m p e r a t u r e and s a l i n i t y measurements were t a k e n a t one meter i n t e r v a l s t h r o u g h o u t t h e month o f August 1970. A Beckman i r i s i t u S a l i n o m e t e r (Model # RS 503 Beckman I n s t r u m e n t s I n c . Cedar Grove, N.J.) w h i c h measured t e m p e r a t u r e and d e r i v e d s a l i n i t y from c o n d u c t i v i t y t o two d e c i m a l p l a c e s was u s e d . Week-l y measurements were t a k e n a t a l l f o u r s i t e s w i t h i n a p e r i o d o f t i m e n o t e x c e e d i n g 100 m i n u t e s . The d a t a a r e p r e s e n t e d i n t h e form o f T/S diagrams i n F i g u r e 3. A l t h o u g h some v a r i a t i o n o c -c u r r e d from week t o week among t h e f o u r s i t e s , p a r t i c u l a r l y i n t h e upper two t o f o u r meters t h i s d i d not f o l l o w any c o n s i s t e n t t r e n d . Hence, t h e s i t e s were n o t c o n s i d e r e d t o be s i g n i f i c a n t l y d i f f e r e n t from one a n o t h e r w i t h r e s p e c t t o t h e s e two f a c t o r s . Data c o v e r i n g t h e e n t i r e y e a r 1970 as w e l l as p a r t o f 1969 a r e a v a i l a b l e f o r t h e e n t r a n c e t o B a m f i e l d I n l e t . Weekly tem-p e r a t u r e measurements from 1 and 5 meters a r e p l o t t e d i n F i g u r e 4 a l o n g w i t h s u r f a c e s a l i n i t i e s . F rond S a m p l i n g and Measurement R e g u l a r monthly c o l l e c t i o n s were made o v e r t h e p e r i o d Feb-r u a r y t h r o u g h August 1970. A d d i t i o n a l c o l l e c t i o n s were made i n O c t o b e r and December. F i v e mature f r o n d s were u s u a l l y c o l l e c t e d from each s i t e a l -though t h i s v a r i e d a t t i m e s from t h r e e t o s i x . S p e c i a l c a r e was t a k e n t o e n s u r e t h a t not more t h a n one f r o n d was o b t a i n e d from each p l a n t d u r i n g a c o l l e c t i o n . Samples were always t a k e n from -9-s u b t i d a l p l a n t s and u s u a l l y from t h e same g e n e r a l p o s i t i o n i n t h e bed. T h e r e f o r e , i t was v e r y p o s s i b l e t h a t more t h a n one f r o n d was c o l l e c t e d from some p l a n t s t h r o u g h o u t t h e s t u d y . A l l c o l l e c t i o n s were made w i t h t h e a i d o f SCUBA. Fronds b e a r i n g , i n t a c t d i s t a l m e r i s t e m a t i c r e g i o n s were s e l -e c t e d on t h e b a s i s o f t h e i r h a v i n g r e a c h e d t h e s u r f a c e , t h e r e b y b e i n g s u b j e c t e d t o t h e f u l l f o r c e o f s u r f a c e waves. However, on s e v e r a l o c c a s i o n s f r o n d s t r a i l i n g a l o n g t h e s u r f a c e a t D i x o n I s l a n d and B a m f i e l d I n l e t were s c a r c e and i t was n e c e s s a r y t o s e l e c t from t h o s e near t h e bottom. I n such i n s t a n c e s f r o n d s o f s u f f i c i e n t l e n g t h t o r e a c h t h e s u r f a c e were u s u a l l y s e l e c t e d . Each s t i p e was c u t a t t h e p o i n t o f c o n t a c t w i t h t h e h o l d -f a s t . The m a t e r i a l was p l a c e d i n a p l a s t i c bag and e i t h e r t r a n s -p o r t e d on i c e t o Vancouver o r measured i n B a m f i e l d . A meter s t i c k was used t o o b t a i n t h e f o l l o w i n g measurements from o u t -s t r e t c h e d f r o n d s : - l e n g t h o f t h e s t i p e from t h e h o l d f a s t t o t h e most d i s t a l s p l i t i n t h e a p i c a l m e r i s t e m a t i c r e g i o n ( d i s c r e p a n c i e s caused by t w i s t i n g o f o l d e r s t i p e s were not c o n s i d e r e d s i g n i f i c a n t ) . -maximum d i a m e t e r o f t h e s t i p e , i n m i l l i m e t e r s , -number o f t e r m i n a l s p l i t s ( i n c o m p l e t e young b l a d e s a t t h e d i s t a l m e r i s t e m a t i c r e g i o n ) , -number o f b l a d e s , i n c l u d i n g t h o s e i n d i c a t e d by t e r m i n a l s p l i t s , -maximum w i d t h o f e v e r y second b l a d e from t h e apex o f t h e f r o n d . Samples were t a k e n o f b l a d e s from p o s i t i o n s 1/2 and 3/4 o f t h e d i s t a n c e from t h e base o f each f r o n d t o t h e apex and were p r e s e r v e d i n 5% f o r m a l i n / s e a w a t e r . The d i m e n s i o n s o f t h e pneu-m a t o c y s t s were l a t e r o b t a i n e d from t h e s e samples. W h i l e some -10-s h r i n k a g e o r s w e l l i n g o f t h e t i s s u e may have r e s u l t e d from t h i s t r e a t m e n t t h e e f f e c t would have been g e n e r a l l y u n i f o r m . Hence, t h e b a s i s f o r c o m p a r i s o n would p r o b a b l y n o t have been a l t e r e d . B l a d e and c o r t e x t h i c k n e s s measurements were t a k e n a t a s t a n d a r d d i s t a n c e o f 15 cm from t h e p n e u m a t o c y s t . I t was f e l t t h a t a t t h i s d i s t a n c e t h e t i s s u e would be mature y e t s t i l l i n -t a c t i n a l a r g e number o f b l a d e s . The t i s s u e was s e c t i o n e d by hand and examined under a N i k o n compound m i c r o s c o p e w i t h phase a t t a c h m e n t s . An e x c e s s o f seawater was used under t h e c o v e r s l i p t o p r e v e n t d i s t o r t i o n . Measurements t o 1.0 m i c r o n s were o b t a i n e d u s i n g a c a l i b r a t e d o c u l a r m i c r o m e t e r . The c o r t e x was t a k e n t o i n c l u d e t h e m e r i s t o d e r m as w e l l as t h e l a r g e r , non-pigmented c o r -t i c a l c e l l s . Due t o e r o s i o n and decay o f b l a d e s , w h i c h was most p r e v a l e n t d u r i n g F a l l and W i n t e r months, i t was not a l w a y s p o s s i b l e t o ob-t a i n a c o m p l e t e s e t o f measurements. O l d e r l a m i n a e were u s u a l l y r e d u c e d c o n s i d e r a b l y i n l e n g t h and were o f t e n a b s e n t e n t i r e l y , l e a v i n g o n l y a s m a l l c l u s t e r o f b l a d e s a t t h e d i s t a l end o f t h e s t i p e . Care was always t a k e n not t o damage t h e p l a n t s d u r i n g s a m p l i n g but f r o n d s from B a m f i e l d I n l e t and D i x o n I s l a n d were p a r t i c u l a r l y d e l i c a t e and e a s i l y t o r n , even by t h e i r own w e i g h t when l i f t e d o u t o f w a t e r . T h i s f a c t o r a l s o tended t o m i n i m i z e t h e a v a i l a b l e d a t a . SPOT SAMPLING STUDY A t o t a l o f 33 samples were t a k e n from 10 k e l p beds c o v e r i n g a w i d e range i n b o t h t i m e and space ( T a b l e 1, F i g . 2 a ) . Exposure was d e t e r m i n e d by s e v e r a l f a c t o r s i n c l u d i n g t h e a n g l e t h r o u g h which t h e s i t e was s u b j e c t e d t o unimpeded winds and t h e maximum and minimum f e t c h . From t h e s e d a t a a l o n g w i t h q u a l -i t a t i v e o b s e r v a t i o n s a t t h e s i t e s a judgement o f t h e exposure was made as a b a s i s f o r c o m p a r i s o n w i t h t h e r e g u l a r s a m p l i n g s t u d y . - 1 1 -M a t e r i a l c o l l e c t e d a t A m p h i t r i t e P o i n t was measured i n Van-c o u v e r , whereas a l l o t h e r m a t e r i a l was measured on b o a r d s h i p . The t e c h n i q u e s o f s a m p l i n g and measurement were t h e same as t h o s e used d u r i n g t h e r e g u l a r s a m p l i n g s t u d y . However, sample b l a d e s were o n l y o b t a i n e d from t h e 1/2 p o s i t i o n f r o m each f r o n d . TRANSPLANT STUDY Methods A s h o r t t i m e b e f o r e t h e t r a n s p l a n t s t u d y was begun a number o f l a r g e , smooth s t o n e s v a r i n g i n d i a m e t e r f r o m about 5 t o 8 i n c h e s were chosen as s u b s t r a t e s f o r t h e young p l a n t s . The s u r -f a c e s were brushed and washed c l e a n o f a l l s c a l e and l o o s e mat-e r i a l . Two a d j a c e n t p a r a l l e l s t r i p s o f l i q u i d s i l i c o n e r u b b e r ( G e n e r a l E l e c t r i c Co.) were a p p l i e d o v e r t h e upper s u r f a c e o f each s t o n e . The m i d d l e s e c t i o n o f t h e s t r i p s was p r e v e n t e d from a c t u a l l y b o n d i n g t o t h e s u r f a c e by a n a r r o w s h e e t o f waxed p a p e r . The s t r i p s were a b l e t o bond t o each o t h e r a l o n g t h e e n t i r e l e n g t h and t o t h e s t o n e a t e i t h e r end. A f t e r t h e r u b b e r had s e t t h e waxed paper was removed and t h e s t r i p s were s e p a r a t e d from one a n -o t h e r a l o n g t h e m i d d l e s e c t i o n w i t h a k n i f e . The p r e p a r e d s t o n e s were numbered t h e n p l a c e d i n p o s i t i o n a t t h e s e l e c t e d s i t e s . A t W i z a r d I s l e t and S c o t t s ' s Bay i t was n e c e s s a r y t o cement them t o t h e bottom. A w a t e r p r o o f cement sup-p l i e d by t h e A l l - C r e t e Mfg. Co. o f Woodland, C a l i f o r n i a was used f o r t h i s p u r p o s e . The t r a n s p l a n t s i t e s a t W i z a r d I s l e t , B a m f i e l d I n l e t and D i x o n I s l a n d were a l l l o c a t e d a t a d e p t h o f about -1.3 f e e t . The d e p t h a t t h e S c o t t ' s Bay s i t e was about -8 f e e t . I n o r d e r t o p r e p a r e t h e s i t e t o r e c e i v e t h e new p l a n t s a s m a l l a r e a o f t h e bottom was c l e a r e d o f a l l l a r g e p l a n t and an-i m a l m a t e r i a l . i t was hoped t h a t t h i s w o u l d r e d u c e c o m p e t i t i o n among t h e p l a n t s . The s i t e was marked w i t h s u r v e y o r ' s t a p e so -12-t h a t i t c o u l d be e a s i l y l o c a t e d i n t i m e s o f poor v i s i b i l i t y . A f t e r t h e s t o n e s were i n p l a c e t h e young p l a n t s were a t t a c h e d by i n s e r t i n g t h e base o f t h e s t i p e between t h e r u b b e r s t r i p s so t h a t t h e h a p t e r a were h e l d f i r m l y a g a i n s t t h e s u r f a c e . An advantage o f u s i n g t h i s t e c h n i q u e i s t h a t i t e n a b l e s one t o use t h e same s u b s t r a t e a number o f t i m e s i n a c o n t i n u o u s t r a n s -p l a n t s t u d y a f t e r t h e mature p l a n t s have been removed ( F i g 5 ) . D e s c r i p t i o n o f T r a n s p l a n t s The p l a n t s used i n t h e s t u d y were, i n most c a s e s , a t about t h e same s t a g e o f development when t h e t r a n s p l a n t s were made. These b o r e a s i n g l e l a m i n a and were, i n a p p e a r a n c e , s i m i l a r t o v a r i o u s o t h e r young l a m i n a r i a l e a n s . However, t h e y were e a s i l y d i s t i n g u i s h e d by t h e p r e s e n c e o f a s h o r t p r i m a r y l o n g i t u d i n a l s p l i t . The f i r s t s e t o f p l a n t s t r a n s f e r r e d t o S c o t t ' s Bay were a t a s l i g h t l y more advanced s t a g e o f development and i n a l l b u t one i n s t a n c e had c o m p l e t e d t h e f i r s t d i c h o t o m y . T h i s was t a k e n i n t o c o n s i d e r a t i o n i n t h e c o m p u t a t i o n o f growth d a t a . The major phase o f t h e t r a n s p l a n t s t u d y c o n s i s t e d o f t r a n s -f e r r i n g p l a n t s from W i z a r d I s l e t t o t h e r e m a i n i n g t h r e e s i t e s . F i v e p l a n t s were t r a n s f e r r e d t o S c o t t ' s Bay on May 17 i n o r d e r t o t e s t t h e t e c h n i q u e . On May 30 two more p l a n t s were added t o t h i s s i t e and f i v e were t r a n s f e r r e d t o each o f t h e r e m a i n i n g l o c a l i t i e s . An a d d i t i o n a l f i v e , s e r v i n g as c o n t r o l s , were p o s i t i o n e d a t W i z -a r d I s l e t . Hence, t h e t o t a l number o f p l a n t s i n i t i a l l y i n v o l v e d i n t h e s t u d y was twenty-two. L o s s e s due t o p h y s i c a l and b i o l o g -i c a l f a c t o r s caused t h i s number t o drop g r a d u a l l y t h r o u g h o u t t h e s t u d y a l t h o u g h r e p l e n i s h m e n t s were made d u r i n g t h e e a r l y s t a g e s . The o n l y s u c c e s s f u l r e p l a c e m e n t was p l a n t number 5 a t w i z a r d I s -l e t w h i c h was p o s i t i o n e d on June 15. A r e c i p r o c a l t r a n s p l a n t was a t t e m p t e d between D i x o n I s l a n d and W i z a r d I s l e t b u t was n o t s u c c e s s f u l . W i t h i n a few weeks a l l -13-p l a n t s t r a n s f e r r e d t o W i z a r d I s l e t were e i t h e r s e v e r e l y damaged o r e n t i r e l y l o s t . A l t h o u g h t h e s e p l a n t s were a t about t h e same s t a g e o f development as t h o s e c o l l e c t e d from W i z a r d I s l e t t h e i r l a m i n a e were c o n s i d e r a b l y w i d e r and t h e t e x t u r e appeared t o be somewhat more d e l i c a t e . These f a c t o r s , combined w i t h t h e g r e a t l y i n c r e a s e d e x p osure a t W i z a r d I s l e t , appear t o have l e d t o t h e i r d e t e r i o r a t i o n . T h i s p r o b l e m was a l s o e n c o u n t e r e d by N o r t o n (1969) when he a t t e m p t e d t o t r a n s f e r p l a n t s from a s h e l t e r e d t o an ex-posed l o c a l i t y . I t was c o n c l u d e d from t h e p r e s e n t a t t e m p t t h a t such a t r a n s f e r m i g h t have been s u c c e s s f u l i f t h e p l a n t s had been o b t a i n e d a t a c o m s i d e r a b l y e a r l i e r s t a g e o f development. As such p l a n t s were no l o n g e r a v a i l a b l e , t h e r e c i p r o c a l t r a n s p l a n t s t u d y was d i s c o n t i n u e d . E v a l u a t i o n o f P l a n t Response Measurements were t a k e n i n s i t u a t two week i n t e r v a l s o v e r a p e r i o d w h i c h v a r i e d w i t h t h e c o n d i t i o n o f each p l a n t . A l l d a t a were r e c o r d e d i n p e n c i l on a s h e e t o f sanded p e r s p e x . The f o l l o w -i n g i n f o r m a t i o n was o b t a i n e d from a s i n g l e p r i m a r y f r o n d from each p l a n t : - s t i p e l e n g t h , -number o f b l a d e s , -number o f t e r m i n a l s p l i t s , - d i m e n s i o n s o f e v e r y second b l a d e from t h e base o f t h e s t i p e . The growth r a t e i n l e n g t h o f i n d i v i d u a l b l a d e s was a s s e s s e d by p u n c h i n g a s m a l l h o l e w i t h a c o r k b o r e r i n t h e c e n t e r o f t h e b l a d e a t a d i s t a n c e o f 10 cm from t h e p n e u m a t o c y s t . I t was n e c -e s s a r y t o p l a c e t h e h o l e s a t 5 cm i n v e r y young b l a d e s i n o r d e r t o p r e v e n t t h e i r l o s s due t o t e r m i n a l e r o s i o n between measurements. E x p a n s i o n o f t h e p e r f o r a t i o n s i n d i c a t e d t h a t s e c o n d a r y growth was p r o b a b l y s t i l l o c c u r i n g between 5 and 10 cm as has been demon-s t r a t e d f o r M a c r o c y s t i s p y r i f e r a by C r i b b ( 1 9 5 3 ) . However, t h i s was n o t c o n s i d e r e d s u f f i c i e n t t o a l t e r t h e r e s u l t s a p p r e c i a b l y . -14-RESULTS CONTINUOUS SAMPLING STUDY Changes Recorded i n Time and P l a c e I n d i v i d u a l f r o n d samples d i d not y i e l d s u f f i c i e n t d a t a t o e n a b l e d i r e c t c o m p a r i s o n s t o be made between l o c a l i t i e s . N e v e r -t h e l e s s , by p r e s e n t i n g each a s p e c t o f t h e h a b i t on a month t o month b a s i s c e r t a i n t r e n d s a r e o f t e n r e v e a l e d and t h e c o n s i s t e n c y w i t h w h i c h t h e y a r e m a i n t a i n e d t h r o u g h o u t t h e y e a r b e a r s p o i n t i n g o u t . S t i p e Diameter Mean s t i p e d i a m e t e r and l e n g t h a r e p l o t t e d a g a i n s t t i m e i n F i g u r e 6. However, b e f o r e t h e s e graphs c a n be i n t e r p r e t e d i t i s n e c e s s a r y t o u n d e r s t a n d how t h e s e two f e a t u r e s r e l a t e t o one an-o t h e r . , • A l i n e a r r e g r e s s i o n a n a l y s i s was c o n d u c t e d f o r each l o c a l i t y t o d e t e r m i n e whether a l i n e a r r e l a t i o n s h i p between maximum d i a -meter and l e n g t h c o u l d be d e f i n e d on t h e b a s i s o f t h e combined d a t a f o r each s i t e . I f such a r e l a t i o n s h i p was d e t e r m i n e d i t was a s s i g n e d an R v a l u e ( l i n e a r c o r r e l a t i o n c o e f f i c i e n t ) w h i c h i s an e x p r e s s i o n o f c o n f i d e n c e and has a maximum v a l u e o f 1. L i n e a r p l o t s a r e superimposed on s c a t t e r diagrams f o r a l l l o c a l i t i e s e x c e p t D i x o n I s l a n d i n F i g u r e 7, and R v a l u e s a r e i n -c l u d e d f o r each s i t e . I n a l l c a s e s t h e r e g r e s s i o n was s i g n i f i c a n t a t t h e 0.01 l e v e l . C o v a r i a n c e a n a l y s e s were used t o d e t e r m i n e whether t h e l i n e a r r e l a t i o n s h i p s d e s c r i b e d i n F i g u r e 6 were s i g n i f i c a n t l y d i f f e r e n t from one a n o t h e r . A l i n e a r r e l a t i o n s h i p between two v a r i a b l e s i s d e f i n e d by t h e e x p r e s s i o n : y = a + b ( x - x ) , a i s t h e mean v a l u e f o r y as d e t e r m i n e d from t h e d a t a ; b r e p r e s e n t s t h e s l o p e . C o n s i d e r i n g o n l y B a m f i e l d I n l e t and S c o t t ' s Bay, t h e p r o b a b i l i t y -15-o f t h e i r a v a l u e s and s l o p e s b e i n g d i f f e r e n t from one a n o t h e r were 0.0540 and 0.1624 r e s p e c t i v e l y . I n n e i t h e r c a s e were t h e s e v a l u e s c o n s i d e r e d s i g n i f i c a n t . Hence, t h e d a t a f o r t h e two s i t e s were combined and compared w i t h W i z a r d I s l e t by t h e same p r o -c e d u r e . I n t h i s c a s e t h e p r o b a b i l i t y v a l u e s f o r a and b were 0.2693 and 0.6583 r e s p e c t i v e l y . Thus t h e t h r e e s i t e s d i d not d i f f e r s i g n i f i c a n t l y from one a n o t h e r . The f a i l u r e t o d e f i n e a l i n e a r r e l a t i o n s h i p f o r D i x o n I s l a n d w i l l be c o n s i d e r e d i n t h e DISCUSSION. R e t u r n i n g t o F i g u r e 6 i t i s now a p p a r e n t t h a t a l t h o u g h t h e R v a l u e s g i v e n i n F i g u r e 7 were g e n e r a l l y low t h e o b s e r v e d f l u c t u a t i o n s i n s t i p e l e n g t h cannot be r u l e d o u t as c o n t r i b u t i n g t o t h e c o r r e s p o n d i n g f l u c t u a t i o n s i n d i a m e t e r w i t h i n t h e s i t e s w i t h t h e e x c e p t i o n o f D i x o n I s l a n d . The c l o s e n e s s o f f i t be-tween t h e s e two f a c t o r s i n F i g u r e 6 s t r e n g t h e n s t h i s c o n c l u s i o n . V a r i a t i o n i n s t i p e d i a m e t e r t h r o u g h o u t t h e s t u d y a r e a was t e s t e d by a p p l y i n g S t u d e n t ' s p a i r e d t - t e s t t o t h e monthly means. Due t o t h e r e l a t i v e l y narrow range o f v a l u e s o b t a i n e d o n l y t h o s e s i t e s r e p r e s e n t i n g t h e o u t e r l i m i t s o f e x p o s u r e (which a l s o c o r -responded t o t h e o u t e r l i m i t s o f mean s t i p e d i a m e t e r s ) were c o n -s i d e r e d . P r o b a b i l i t y v a l u e s f o r common means a r e as f o l l o w s : W i z a r d I s l e t v s . B a m f i e l d I n l e t 0.1 W i z a r d I s l e t v s . D i x o n I s l a n d 0.01 B a m f i e l d I n l e t d i d n o t d i f f e r s i g n i f i c a n t l y i n mean s t i p e d i a m e t e r from W i z a r d I s l e t . T h i s may be r e l a t e d t o t h e s i m i l a r -i t y o f t h e i r mean s t i p e l e n g t h s , p a r t i c u l a r l y as a l i n e a r r e -l a t i o n s h i p has been d e f i n e d f o r b o t h s i t e s ( F i g u r e 7 ) . As a l i n e a r r e l a t i o n s h i p was not d e f i n e d f o r D i x o n I s l a n d t h e s i g n i f -i c a n t d i f f e r e n c e i n mean d i a m e t e r from W i z a r d I s l e t s t r o n g l y s u g g e s t s t h a t t h e d i a m e t e r o f t h e s t i p e i s r e l a t e d t o t h e amount o f w a t e r movement. T h i s r e l a t i o n s h i p i s d e m o n s t r a t e d c o n s i s t e n t -l y t h r o u g h o u t t h e y e a r . -16-Th e s e a s o n a l i t y i n s t i p e d i a m e t e r shown by D i x o n I s l a n d i n F i g u r e 6 can be e x p l a i n e d i n l i g h t o f t h e above c o n c l u s i o n s . As t h e maximum growth p e r i o d f o r an i n d i v i d u a l f r o n d i s about s i x months (see pg. 2 1 and a l s o N o r t h , 1971) t h e o c c u r r e n c e o f t h e l a r g e s t v a l u e s f o r mean s t i p e d i a m e t e r t h r o u g h l a t e s p r i n g and e a r l y summer r e p r e s e n t s a r e s p o n s e t o dynamic c o n d i t i o n s as t h e y e x i s t e d d u r i n g t h e p r e v i o u s w i n t e r and e a r l y s p r i n g ( T a b l e 1 ) . Hence, t h e s e f r o n d s d i f f e r e d l e a s t from t h o s e sampled a t W i z a r d I s l e t d u r i n g t h i s p e r i o d o f t h e y e a r . The l a t e summer and f a l l d e c r e a s e i n d i a m e t e r can be a t t r i b u t e d t o t h e f a c t t h a t t h e p l a n t s c o l l e c t e d a t t h i s t i m e o f y e a r would have grown under v e r y s h e l t e r e d c o n d i t i o n s . S t i p e L e n g t h V a r i a t i o n s w i t h i n and between l o c a l i t i e s w i t h r e s p e c t t o s t i p e l e n g t h was t o o l a r g e t o r e v e a l any p a t t e r n , w i t h t h e p o s -s i b l e e x c e p t i o n o f D i x o n I s l a n d where v a l u e s remained g e n e r a l l y low t h r o u g h o u t t h e y e a r . Samples were not alway o b t a i n e d from e x a c t l y t h e same d e p t h , p a r t i c u l a r l y a t B a m f i e l d I n l e t . O t h e r v a r i a b l e s w h i c h were not c o n t r o l l e d i n c l u d e age and p o s s i b l y growth r a t e . Hence, f u r t h e r c o n s i d e r a t i o n o f t h e r e -l a t i o n s h i p s between w a t e r movement and s t i p e l e n g t h must a w a i t t h e r e s u l t s o f t h e r e m a i n i n g two s t u d i e s . D i s t a l M e r i s t e m a t i c R e g i o n The mean number o f t e r m i n a l s p l i t s f o r f r o n d s from each l o c a l i t y i s p l o t t e d a g a i n s t t i m e i n F i g u r e 8 and maximum and min-imum v a l u e s a r e i n c l u d e d . S t u d e n t ' s p a r i e d t - t e s t was r u n and p r o b a b i l i t y v a l u e s f o r common means a r e as f o l l o w s : W i z a r d I s l e t v s . S c o t t ' s Bay 0.2 W i z a r d I s l e t v s . B a m f i e l d I n l e t 0.05 W i z a r d I s l e t v s . D i x o n I s l a n d 0.05 -17-These d a t a s u g g e s t t h a t r a p i d w a t e r movement enhances t h e accum-u l a t i o n o f t e r m i n a l s p l i t s and t h i s t r e n d i s c o n s i s t e n t t h r o u g h -out t h e y e a r . However, t h e common s e a s o n a l i t y i n d i c a t e d by a l l s i t e s , w i t h t h e e x c e p t i o n o f D i x o n I s l a n d , does not appear t o be r e l a t e d t o t h i s e f f e c t as dynamic c o n d i t i o n s were l e a s t s e v e r e d u r i n g s p r i n g and summer months. The i m p o r t a n c e o f o t h e r v a r -i a b l e s such as age and t i s s u e d e t e r i o r a t i o n w i l l be c o n s i d e r e d i n t h e DISCUSSION. B l a d e s : Number i n r e l a t i o n t o s t i p e l e n g t h The a n a l y s i s a p p l i e d t o s t i p e d i a m e t e r was used t o t e s t f o r a l i n e a r r e l a t i o n s h i p between t h e number o f l a m i n a e and t h e l e n g t h o f t h e s t i p e f o r each l o c a l i t y . The r e s u l t s a r e p r e s e n t e d d i a -g r a m a t i c a l l y i n F i g u r e 9 and R v a l u e s a r e i n c l u d e d . I n a l l i n -s t a n c e s t h e p r o b a b i l i t y o f t h e s l o p e b e i n g e q u a l t o 0 was l e s s t h a n 0.01. C o v a r i a n c e a n a l y s e s were used t o compare l o c a l i t i e s and p r o b -a b i l i t e s f o r s i g n i f i c a n t d i f f e r e n c e s between s i t e s w i t h r e s p e c t t o v a l u e s a and b were as f o l l o w s : a b B a m f i e l d I n l e t v s . W i z a r d I s l e t 0.0386 0.5491 B . I . + W.I. v s . S c o t t ' s Bay 0.0661 0.3385 B . I . + W.I. v s . D i x o n I s l a n d 0.2286 0.4576 Thus t h e r e was found t o be no s i g n i f i c a n t v a r i a t i o n among t h e f o u r l o c a l i t i e s . W i d t h o f Mature Laminae There were s e v e r a l problems i n v o l v e d i n c o m p a r i n g d a t a on w i d t h o f mature b l a d e s . To r e d u c e t h e e f f e c t o f v a r i a t i o n w i t h -i n each p l a n t i t was n e c e s s a r y t h a t as many b l a d e s as p o s s i b l e be c o n s i d e r e d . I f t h e c o m p a r i s o n was t o be b ased on i n d i v i d u a l sam-p l e s , t h e n as many p l a n t s as p o s s i b l e w o u l d have t o be i n c l u d e d . -18-I t was a l s o e s s e n t i a l t h a t t h e same amount o f d a t a be.drawn from each l o c a l i t y . The m a t t e r was f u r t h e r c o m p l i c a t e d by t h e h i g h degree o f v a r i a b i l i t y i n t h e number o f i n t a c t b l a d e s p r e s e n t on. each f r o n d . However, i t was p o s s i b l e t o o b t a i n s u f f i c i e n t d a t a t o t e s t f o r v a r i a t i o n among p o p u l a t i o n s w h i l e t a k i n g a l l o f t h e s e f a c t o r s i n t o c o n s i d e r a t i o n . D u r i n g A p r i l , f o r example, t h e most b a d l y d e t e r i o r a t e d f r o n d s were c o l l e c t e d from B a m f i e l d I n l e t . From t h a t sample two f r o n d s b o r e t h r e e i n t a c t mature b l a d e s , one b o r e two mature b l a d e s and t h e f o u r t h f r o n d d i d not bear any. I n o r d e r t o use a maximum number o f f r o n d o n l y t h e f i r s t two mature b l a d e s on each o f t h e f i r s t t h r e e f r o n d s were c o n s i d e r e d . T h i s s t a n d a r d number o f f r o n d s and b l a d e s was t h e n a p p l i e d t o t h e r e m a i n i n g t h r e e samples from t h e A p r i l c o l l e c t i o n . From t h e June c o l l e c t i o n , on t h e o t h e r hand, a s t a n d a r d num-ber o f f o u r f r o n d s and f o u r b l a d e s was u s e d . Due t o t h e n a t u r e o f t h i s a n a l y s i s t h e r e were always some samples f o r w h i c h t h e r e were more s u i t a b l e f r o n d s t h a n c o u l d be u s e d . I n such c a s e s t h e l a s t f r o n d s on t h e d a t a s h e e t s were e l i m i n a t e d f i r s t as t h e y were meas-u r e d i n random o r d e r . The d a t a o b t a i n e d i n t h i s way f o r each c o l l e c t i o n were sub-j e c t e d t o a t h r e e f a c t o r a n a l y s i s o f v a r i a n c e , v a r i a t i o n among p l a n t s due t o genotype o r t o e n v i r o n m e n t - p l a n t i n t e r a c t i o n s were l a t e r i g n o r e d as t h e o b j e c t o f t h e s t u d y was t o t e s t f o r s i g n i f -i c a n t d i f f e r e n c e s among t h e o v e r a l l p o p u l a t i o n s . The a c t u a l v a r i a n c e among t h e f o u r l o c a l i t i e s was compared w i t h t h e c a l c u l a t e d v a r i a n c e based on t h e n u l l h y p o t h e s i s ( t h a t t h e p o p u l a t i o n means a r e e q u a l ) . The r a t i o o f t h e r e c o r d e d v a r i -ance t o t h e c a l c u l a t e d v a r i a n c e i s termed t h e v a r i a n c e r a t i o and i s d e s i g n a t e d F. The F v a l u e s and p r o b a b i l i t y v a l u e s f o r common means f o r t h e f i n a l seven c o l l e c t i o n s a r e p r e s e n t e d a l o n g w i t h -19-sample s i z e s i n T a b l e 2. Due t o i n s u f f i c i e n t d a t a t h e f i r s t two c o l l e c t i o n s were not i n c l u d e d i n t h e a n a l y s i s . Mean b l a d e w i d t h i s p l o t t e d a g a i n s t t i m e f o r each l o c a l i t y i n F i g u r e 10. A s i g n i f i c a n t l e v e l o f v a r i a t i o n i s shown t o o c c u r among t h e f o u r s i t e s o v e r much o f t h e y e a r . The n a t u r e o f t h i s v a r i a t i o n i s such as t o s u g g e s t t h a t i n c r e a s i n g e x p o s u r e i s d i r e c t l y r e l a t e d t o t h e f o r m a t i o n o f n a r r o w e r b l a d e s . Assuming t h i s t o be t h e c a s e , t h e s e t o f v a l u e s o b t a i n e d from D i x o n I s l a n d a r e somewhat l o w e r t h a n e x p e c t e d . T h i s may be r e -l a t e d t o t h e g e n e r a l l y poor c o n d i t i o n o f t h e f r o n d s c o l l e c t e d from t h a t s i t e . F i g u r e 11 shows a t y p i c a l s i t u a t i o n w h e r e i n a l l o f t h e m i d d l e t o l o w e r b l a d e s have d e t e r i o r a t e d by t h e t i m e t h e f r o n d has r e a c h e d t h e s u r f a c e . S a r g e n t and L a n t r i p (1952) and P a r k e r (1965) dem o n s t r a t e d t h a t young b l a d e s near t h e apex o f t h e f r o n d depend t o a l a r g e e x t e n t on t h e i m p o r t a t i o n o f m e t a b o l i t e s from l o w e r r e -g i o n s o f t h e p l a n t . I n t h e absence o f t h i s s o u r c e o f m e t a b o l i t e s t h e development o f young b l a d e s near t h e s u r f a c e may have been a r -r e s t e d . As i n t h e c a s e o f t e r m i n a l s p l i t s a s e a s o n a l i t y i s i n d i c a t e d w h i c h i s not d i r e c t l y c o r r e l a t e d w i t h e x p o s u r e c o n d i t i o n s and a l -t e r n a t i v e e x p l a n a t i o n s must a w a i t t h e r e s u l t s o f t h e r e m a i n i n g s t u d i e s . Changes Recorded O n l y i n Space Due t o b l a d e a t r o p h y i t was not p o s s i b l e t o o b t a i n a c o m p l e t e s e t o f samples from e v e r y c o l l e c t i o n . B l a d e s were o b t a i n e d most c o n s i s t e n t l y from a l l l o c a l i t i e s d u r i n g t h e months o f A p r i l , May and June. Hence, co m p a r i s o n s were made on t h e b a s i s o f one o v e r -a l l c o l l e c t i o n c o v e r i n g t h i s p e r i o d . F o r each s e t o f d a t a o b t a i n e d from t h e sample b l a d e s a one f a c t o r a n a l y s i s o f v a r i a n c e was c o n d u c t e d . V a r i a n c e r a t i o s were d e t e r m i n e d and S c h e f f e ' s t e s t f o r m u l t i p l e c o m p a r i s o n s w i t h sam--20-p l e s o f u n e q u a l s i z e was c o n d u c t e d . T h i s p e r m i t t e d c o m p a r i s o n s t o be made between s p e c i f i c l o c a l i t i e s . The r e s u l t s o f t h i s t e s t a r e e x p r e s s e d i n t h e form o f p r o b a b i l i t y v a l u e s f o r common means. These a n a l y s e s were used t o t e s t f o r s i g n i f i c a n t v a r i a t i o n i n t h e f o l l o w i n g f e a t u r e s : b l a d e t h i c k n e s s , c o r t e x : m e d u l l a r a t i o , mean s p i n e l e n g t h and pneumatocyst l e n g t h and d i a m e t e r . O n l y t h e l o w e r b l a d e s were used and t h e r e s u l t s o f t h e a n a l y s e s a r e p r e -s e n t e d i n T a b l e 3. Mean v a l u e s f o r t h e 1/2 and 3/4 p o s i t i o n s a r e i n c l u d e d a l o n g w i t h s t a n d a r d e r r o r s o f t h e means and maxima and minima. These d a t a were e x p e c t e d t o r e f l e c t e n v i r o n m e n t a l c o n d i t i o n s as t h e y e x i s t e d i n t h e B a m f i e l d r e g i o n t h r o u g h o u t e a r l y and l a t e s p r i n g . Due t o t h e h i g h degree o f v a r i a t i o n w i t h i n i n d i v i d u a l p l a n t s i t i s d i f f i c u l t t o draw o t h e r t h a n t e n t a t i v e c o n c l u s i o n s . There was u s u a l l y an absence o f any p a t t e r n t o t h i s v a r i a t i o n r e l -a t i v e t o e x p o s u r e . However, i t i s v e r y l i k e l y t h a t some d i s c r i p -ancy may have been caused by t h e i n c l u s i o n o f immature b l a d e s from t h e 3/4 p o s i t i o n . Those f e a t u r e s w h i c h appear t o be most r e s p o n s i v e t o w a t e r movement a r e l a m i n a t h i c k n e s s , s p i n e l e n g t h and pneumatocyst d i a -m e ter. The o c c u r r a n c e o f t h e s h o r t e s t b l a d d e r s a t D i x o n I s l a n d i s c o n s i s t e n t w i t h t h e f i n d i n g s r e g a r d i n g pneumatocyst d i a m e t e r . Hence, a t r e n d toward t h e f o r m a t i o n o f pneumatocysts o f s m a l l e r c a p a c i t y i n l e s s exposed e n v i r o n m e n t s i s s u g g e s t e d . T h i s does not n e c e s s a r i l y c o n f l i c t w i t h e a r l i e r s t a t e m e n t s r e g a r d i n g s e a s o n a l e f f e c t s o f e x p osure on s t i p e d i a m e t e r a t D i x o n I s l a n d as t h e c h a r -a c t e r i s t i c s o f i n d i v i d u a l b l a d e s would be e x p e c t e d t o r e f l e c t a more r e c e n t dynamic e n v i r o n m e n t . Spot S a m p l i n g Study Data o b t a i n e d from t h e s p o t s a m p l i n g s t u d y a r e p r e s e n t e d a l o n g w i t h mean v a l u e s i n T a b l e s 4 and 5. O n l y t h e f i r s t t h r e e t o f o u r b l a d e s from each f r o n d were c o n s i d e r e d i n t h e d e t e r m i n a t i o n o f b l a d e w i d t h s i n o r d e r t o f a c i l i t a t e c o m p a r i s o n s w i t h t h e r e s u l t s o f t h e c o n t i n u o u s s a m p l i n g s t u d y . Those f e a t u r e s w h i c h seem t o be most d i r e c t l y i n f l u e n c e d by exposure c o n d i t i o n s a r e s t i p e d i a m e t e r , b l a d e w i d t h and t h i c k n e s s and pneumatocyst d i m e n s i o n s . The d a t a do n o t i n d i c a t e a d i r e c t c o r r e l a t i o n o f t h e f o l l o w i n g w i t h e x p o s u r e : t h e r e l a t i v e number o f b l a d e s , t e r m i n a l s p l i t s , c o r t e x : m e d u l l a r a t i o s and s p i n e l e n g t h . The same a l s o a p p l i e s t o s t i p e l e n g t h b u t i n t h i s i n s t a n c e t h e d e p t h o f w a t e r and age must a l s o be c o n s i d e r e d . T r a n s p l a n t Study The t r a n s p l a n t s t u d y was t e r m i n a t e d by f r o n d a t r o p h y a t a l l l o c a l i t i e s e x c e p t w i z a r d I s l e t . However, a l l f i n a l measurements o f s t i p e l e n g t h and b l a d e number a r e v a l i d as t h e p l a n t s s t i l l c o n t a i n e d c o m p l e t e p r i m a r y f r o n d s a l t h o u g h t h e i n d i v i d u a l b l a d e s and a p i c a l m e r i s t e m a t i c r e g i o n s were o f t e n b a d l y d e t e r i o r a t e d . The l a s t r e m a i n i n g p l a n t s were c o l l e c t e d f r om a l l l o c a l i t i e s on December 5 a f t e r 199 d a y s . Growth o f P r i m a r y Fronds The l e n g t h s o f t h e p r i m a r y f r o n d s a r e p l o t t e d a g a i n s t t i m e f o r each l o c a l i t y i n F i g u r e 12. S t u d e n t ' s p a i r e d t - t e s t was ap-p l i e d t o t h e mean s l o p e s o f t h e e x p o n e n t i a l phase f o r a l l s i t e s . V a l u e s f o r w i z a r d I s l e t d i f f e r e d s i g n i f i c a n t l y from t h o s e o f a l l o t h e r s i t e s . . .. Mean d a i l y i n c r e m e n t s i n cm p e r day and (p = 0.05) 2 . i n i t i a t i o n r a t e s f o r new b l a d e s were d e t e r m i n e d from c o n s e c u t i v e r e a d i n g s and a r e p r e s e n t e d i n T a b l e 6. The g r o w t h r a t e s o f i n d i v i d u a l f r o n d s show a d i s t i n c t c o r -r e l a t i o n w i t h e x p o s u r e . N e i t h e r t h e g r e a t e r d e p t h nor t h e den-s i t y o f t h e s u r f a c e canopy appear t o have a f f e c t e d t h e growth r a t e o f s t i p e s a t S c o t t ' s Bay. T h i s i s c o n s i s t e n t w i t h t h e f i n d -i n g s o f N e u s h u l and Haxo ( 1 9 6 3 ) . Growth was c h a r a c t e r i z e d a t a l l s i t e s by a s l o w growth phase f o l l o w e d by a p e r i o d o f r a p i d e l o n g -a t i o n and b l a d e i n i t i a t i o n . The maximum e l o n g a t i o n r a t e o f 8 cm/ day t h r o u g h o u t t h e e x p o n e n t i a l phase compares f a v o r a b l y w i t h t h e p r e v i o u s maximum r e c o r d i n g o f about 7.9 cm/day f o r t h e same s p e c -i e s i n l o c a l w a t e r s ( S c a g e l , 1 9 4 8 ) . Growth o f Laminae Maximum d a i l y i n c r e m e n t s o f i n d i v i d u a l b l a d e s were d e t e r -mined from t h e d i s t a n c e c o v e r e d by r e f e r e n c e marks between c o n -s e c u t i v e r e a d i n g s and a r e p r e s e n t e d i n T a b l e 7. A one f a c t o r an-a l y s i s o f v a r i a n c e was used t o t e s t f o r s i g n i f i c a n t d i f f e r e n c e s between l o c a l i t i e s . O n l y t h e f a s t e s t g r o w i n g b l a d e from each p l a n t was c o n s i d e r e d i n each c a s e as t h i s was assumed t o r e p r e -s e n t t h e o p t i m a l r a t e o f g r o w t h . The r e s u l t s a r e a l s o p r e s e n t e d i n t h e above t a b l e . These d a t a do not i n d i c a t e a r e l a t i o n s h i p be tween growth o f l a m i n a e and w a t e r movement. The c o n s i s t e n t o c c u r ence o f low v a l u e s f o r S c o t t ' s Bay s u g g e s t s t h a t l i g h t may be t h e c o n t r o l l i n g f a c t o r i n b l a d e e l o n g a t i o n as t h e s e p l a n t s were grow-i n g i n deeper w a t e r t h a n t h e o t h e r s and were a l s o i n f l u e n c e d t o a g r e a t e r e x t e n t by t h e s u r f a c e canopy. B l a d e s P e r U n i t Lenqht o f S t i p e I t i s a p p a r e n t from T a b l e 4 t h a t t h e number o f b l a d e s p e r u n i t l e n g t h o f s t i p e i s n o t a f u n c t i o n o f e x p o s u r e . A l t h o u g h p l a n t s g r o w i n g i n more exposed l o c a l i t i e s a r e c h a r a c t e r i z e d by h i g h e r b l a d e i n i t i a t i o n r a t e s ( T a b l e 6 ) , t h i s i s c o u n t e r a c t e d by c o r r e s p o n d i n g d i f f e r e n c e s i n t h e growth o f t h e s t i p e s . I n T a b l e 8 t h e age o f t h e f r o n d i s c o n s i d e r e d and t h e r a t i o o f t h e number o f b l a d e s t o t h e l e n g t h o f t h e s t i p e i s shown t o d e c r e a s e s t e a d -i l y w i t h t i m e . T h i s s u p p o r t s t h e c o n t e n t i o n t h a t d i f f e r e n c e s be-tween l o c a l i t i e s w i t h r e s p e c t t o t h i s f e a t u r e cannot be d i r e c t l y a t t r i b u t e d t o e x p o sure c o n d i t i o n s . - 2 3 -Lamina W i d t h D i r e c t c o m p a r i s o n s between l o c a l i t i e s w i t h r e s p e c t t o b l a d e d i m e n s i o n s c o u l d n o t be made a t t h e t i m e o f each r e c o r d i n g as t h e development o f t h e p l a n t s was o u t o f phas e . P l a n t s w i t h l a r g e r numbers o f b l a d e s were n a t u r a l l y c l o s e r t o t h e s u r f a c e so t h a t b l a d e s f o r m i n g near t h e apex were s u b j e c t t o d i f f e r e n t e n v i r o n -m e n t a l c o n d i t i o n s . Comparisons c o u l d , however, be made by c o n -s i d e r i n g o n l y mature b l a d e s a t t h e same p o s i t i o n on each p l a n t . T h i s was o n l y made p o s s i b l e by t h e s h o r t p e r i o d o f t i m e o v e r w h i c h t h e e x p e r i m e n t was c o n d u c t e d . Maximum w i d t h s a r e g i v e n f o r ma-t u r e b l a d e s numbered from t h e base o f t h e f r o n d f o r a l l l o c a l -i t i e s i n T a b l e 9 . These d a t a s u p p o r t t h e p r e v i o u s f i n d i n g s r e -g a r d i n g b l a d e w i d t h and s u g g e s t t h a t t h e w i d e range o f v a l u e s r e -co r d e d t h r o u g h o u t t h e B a m f i e l d r e g i o n a r e w i t h i n t h e c a p a c i t y o f t h e i n d i v i d u a l p l a n t . i DISCUSSION C o n s i d e r i n g t h e r e l a t i v e l y narrow r a n g e o f e x p o s u r e c o v e r e d by t h e c o n t i n u o u s s a m p l i n g s t u d y i t i s n o t s u r p r i s i n g t h a t t h e m o r p h o l o g i c a l d i f f e r e n c e s between c o n s e c u t i v e l o c a l i t i e s were no t more d i s t i n c t . I n most c a s e s t h e t r e n d s e s t a b l i s h e d t h r o u g h t h e c o n t i n u o u s s a m p l i n g s t u d y have p r o v e n t o be c o n s i s t e n t o v e r a wide g e o g r a p h i c r a n g e . When o n l y t h o s e l o c a l i t i e s r e p r e s e n t -i n g t h e extremes o f e x p osure a r e c o n s i d e r e d t h e t r e n d s a r e o f t e n more c l e a r l y d e f i n e d . I n such i n s t a n c e s t h e o c c u r r e n c e o f i n t e r -m e d i a t e v a l u e s a t t h e r e m a i n i n g s i t e s s u g g e s t s t h e p r e s e n c e o f a h i g h l y s e n s i t i v e c o n t r o l l i n g mechanism. A l t h o u g h each o f t h e t h r e e s t u d i e s d e a l s w i t h a p a r t i c u l a r a s p e c t o f t h e r e l a t i o n s h i p between morphology and e x p o s u r e , t h e f u l l s i g n i f i c a n c e o f t h e r e s u l t s can o n l y be a p p r e c i a t e d by i n -c o r p o r a t i n g them i n t o an o v e r a l l t r e a t m e n t o f t h e p r o b l e m . The f o l l o w i n g d i s c u s s i o n d e a l s w i t h i n d i v i d u a l a s p e c t s o f t h e mor-ph o l o g y i n t h i s manner. S t i p e D iameter The i m p o r t a n c e o f exposure i n t h e d e t e r m i n a t i o n o f s t i p e d i a m e t e r can o n l y be seen i n i t s p r o p e r p e r s p e c t i v e i f t h e e f f e c t s o f o t h e r f a c t o r s such as t h e age o f t h e p l a n t and t h e l e n g t h o f t h e s t i p e a r e u n d e r s t o o d . C l e n d e n n i n g (1971) has d e s c r i b e d a r e l a t i o n s h i p between t h e age o f t h e p l a n t and d i a m e t e r o f t h e s t i p e s i t p r o d u c e s . F i r s t g e n e r a t i o n f r o n d s o f M a c r o c y s t i s p y r i f e r a were g e n e r a l l y t h i n n e r , d a r k e r c o l o u r e d and l e s s l i k e l y t o w i t h s t a n d t h e f o r c e s g e n e r -a t e d by s t r o n g wave a c t i o n t h a n l a t e r f r o n d s on t h e same p l a n t . Fronds were c o l l e c t e d t h r o u g h o u t t h e p r e s e n t s t u d y w i t h o u t r e -g a r d t o h i e r a r c h y and i t i s l i k e l y t h a t i f s u c h a r e l a t i o n s h i p does a p p l y t o t h i s s p e c i e s , i t would have a f f e c t e d t h e r e c o r d e d -25-v a l u e s f o r s t i p e d i a m e t e r u n i f o r m l y . F i r s t g e n e r a t i o n f r o n d s o f c o n t r o l p l a n t s a t W i z a r d I s l e t , however, d i d manage t o r e a c h t h e s u r f a c e and appeared no l e s s v i g o r o u s t h a n s e c o n d a r y and t e r t i a r y f r o n d s on t h e same p l a n t s . A l t h o u g h i t i s p o s s i b l e t o d e f i n e a l i n e a r r e l a t i o n s h i p be-tween s t i p e d i a m e t e r and l e n g t h ( F i g . 7 ) i t has been d e m o n s t r a t e d t h a t t h i s cannot always be used t o e x p l a i n s e a s o n a l f l u c t u a t i o n s w i t h i n s p e c i f i c l o c a l i t i e s . A t D i x o n I s l a n d t h e s e a b e r r a n t f l u c t -u a t i o n s a r e a t t r i b u t e d t o s e a s o n a l changes i n e x p o s u r e . W h i l e t h e l i n e a r r e l a t i o n s h i p c o u l d a l s o be used t o e x p l a i n d i f f e r e n c e s w h i c h o c c u r between l o c a l i t i e s t h e r e a r e s i t u a t i o n s where t h i s does not a p p l y . The mean s t i p e l e n g t h was s i m i l a r f o r A m p h i t r i t e P o i n t , R a g l a n P o i n t and P o r t H a r d y . However, t h e d i a -meters v a r i e d i n such a way as t o s u g g e s t t h a t d e c r e a s i n g e x p o sure r e s u l t s i n n a r r o w e r s t i p e s The same c o n c l u s i o n can be drawn from a c o m p a r i s o n between S c o t t ' s Bay and W i z a r d I s l e t and t h e more ex-posed s i t e a t Hope I s l a n d . The narrow range o f s t i p e d i a m e t e r s r e c o r d e d from many s i t e s and t h e f a c t t h a t t h e R v a l u e s i n F i g u r e 7 a r e not s i g n i f i c a n t l y l a r g e s u g g e s t t h a t i t may be p o s s i b l e t o compare many l o c a l i t i e s w i t h o u t r e g a r d t o s t i p e l e n g t h . Under t h e s e c o n d i t i o n s a r e l a t i o n -s h i p between s t i p e d i a m e t e r and exposure becomes more a p p a r e n t . T a b l e 4 d e m o n s t r a t e s t h a t t h i s r e l a t i o n s h i p a p p l i e s o v e r a w i d e g e o g r a p h i c a r e a w h i l e i n t h e B a m f i e l d r e g i o n ( F i g . 6 ) , i t has been shown t o a p p l y r e l a t i v e l y c o n s i s t e n t l y t h r o u g h o u t t h e y e a r . Due t o f r o n d a t r o p h y d a t a s u p p o r t i n g t h e s e c o n c l u s i o n s were n o t ob-t a i n e d from t h e t r a n s p l a n t s t u d y . The f u n c t i o n a l s i g n i f i c a n c e o f t h i s r e l a t i o n s h i p i s o b v i o u s but i s c o m p l i c a t e d by t h e f a c t t h a t i n most c a s e s t h e t h i c k e s t r e g i o n o f t h e s t i p e o c c u r r e d some d i s t a n c e from t h e h o l d f a s t . The same phenomenon has a l s o been r e p o r t e d by S c a g e l (1948) and C r i b b -26-( 1 9 5 4 ) . However, t h i s does not n e c e s s a r i l y c o n f l i c t w i t h t h e a s -s e r t i o n t h a t s t i p e d i a m e t e r i s r e l a t e d t o e x p o s u r e . By t h e t i m e a f r o n d has become s u b j e c t e d t o t h e f u l l f o r c e o f s u r f a c e waves i t s l o w e r p o r t i o n s have a l r e a d y c e ased t o e l o n -g a t e . The p l a n t may a l l o w f o r t h i s by p r o d u c i n g a s t i p e o f much g r e a t e r s t r e n g t h d u r i n g t h e e a r l i e r phases o f growth t h a n i s a c -t u a l l y r e q u i r e d a t t h a t t i m e , A l e s s t e l e o l o g i c a l i n t e r p r e t a t i o n , on t h e o t h e r hand, i s t h a t a s t i p e o f s u f f i c i e n t d i a m e t e r t o w i t h -s t a n d t h e s t r e s s e s o c c u r r i n g d u r i n g i t s f o r m a t i o n i s l a t e r s t r e n g t h -ened t h r o u g h t h e i n c o r p o r a t i o n o f m e t a b o l i t e s from o t h e r r e g i o n s o f t h e p l a n t . S a r g e n t and L a n t r i p (1952) and P a r k e r (1965) found t h a t v a r i o u s s u b s t a n c e s were t r a n s p o r t e d downward from more d i s t a l r e g i o n s o f t h e p l a n t . S t i p e t i s s u e f o r m i n g f u r t h e r from t h e h o l d -f a s t and d u r i n g t h e r a p i d phase o f e l o n g a t i o n would become sub-j e c t e d t o s t r o n g e r dynamic f o r c e s b e f o r e i t had matured, r e s u l t -i n g i n a c o r r e s p o n d i n g i n c r e a s e i n t h i c k n e s s . I n a c c o r d a n c e w i t h t h e above i n t e r p r e t a t i o n i t i s now a p p a r -ent t h a t p l a n t s s u b j e c t e d t o maximum ex p o s u r e d u r i n g e a r l y s t a g e s o f growth would not show a l i n e a r r e l a t i o n s h i p between s t i p e d i a -meter and l e n g t h l a t e r i n t h e i r development. A t A m p h i t r i t e P o i n t , f o r example, t h e p l a n t s were c o l l e c t e d s l i g h t l y s u b t i d a l l y i n a s u r g e c h a n n e l and t h e d i a m e t e r s o f t h e i r s t i p e s were l a r g e i n s p i t e o f t h e i r s h o r t l e n g t h s . The p l a n t s a t D i x o n i s l a n d , on t h e o t h e r hand, were not s u b j e c t t o t u r b u l e n c e d u r i n g summer months. T h i s r e s u l t e d i n t h e f o r m a t i o n o f u n i f o r m l y n arrow s t i p e s and a l i n e a r r e l a t i o n s h i p was not d e f i n e d . That t h i s a p p l i e s t o a l e s s e r e x t e n t t h r o u g h o u t t h e B a m f i e l d r e g i o n i s d e m o n s t r a t e d by F i g u r e 7. A l a r g e range o f v a l u e s f o r s t i p e l e n g t h i s always a s -s o c i a t e d w i t h a r e l a t i v e l y narrow range o f d i a m e t e r s and t h e l i n -e a r r e l a t i o n s h i p s were weak. The maximum d i a m e t e r r e c o r d e d t h r o u g h o u t t h e o v e r a l l s t u d y - 2 7 -i s e x p e c t e d t o r e f l e c t d y n a m i c c o n d i t i o n r a t h e r t h a n s t i p e l e n g t h . H e n c e , a v a l u e o f 12 mm was r e c o r d e d f o r two f r o n d s w h i c h d i f f e r e d i n l e n g t h by a f a c t o r o f t w o . T h i s a p p e a r s t o be t h e o p t i m a l s t i p e d i a m e t e r f o r t h e s p e c i e s i n C a n a d a i n w a t e r s ( s e e a l s o S c a g e l , 1 9 4 8 ) . S t i p e L e n g t h The l e n g t h o f t h e s t i p e i s a f u n c t i o n o f b o t h d e p t h a n d e x -p o s u r e . As t h e p l a n t g r o w s t h r o u g h t h e w a t e r c o l u m n i t comes i n -c r e a s i n g l y u n d e r t h e i n f l u e n c e o f wave a c t i o n and t i d a l c u r r e n t s . The r e s i s t a n c e c r e a t e d b y t h e b l a d e s c a u s e s t h e s t i p e t o assume a d i a g o n a l p o s i t i o n r e l a t i v e t o t h e s u r f a c e . H e n c e , b y t h e t i m e t h e a p e x h a s r e a c h e d t h e s u r f a c e t h e l e n g t h o f t h e s t i p e i s much g r e a t e r t h a n t h e d e p t h o f w a t e r o v e r t h e h o l d f a s t . T h r o u g h o u t t h e e n t i r e s t u d y t h e r e was f o u n d t o b e v e r y l i t t l e v a r i a t i o n i n t h e l e n g t h o f t h a t p o r t i o n o f t h e f r o n d t r a i l i n g a l o n g t h e s u r -f a c e o t h e r t h a n t h a t w h i c h c o u l d be a t t r i b u t e d t o t h e v a r i e d p o s -i t i o n o f t h e t i d e , a l o n g w i t h p o s s i b l e s e a s o n a l e f f e c t s . G r o w t h , t h e r e f o r e , a p p e a r s t o c e a s e s h o r t l y a f t e r t h e f r o n d h a s r e a c h e d t h e s u r f a c e , r e g a r d l e s s o f d y n a m i c c o n d i t i o n s . I n s h e l t e r e d l o c a l i t i e s t h e f r o n d s w e r e a b l e t o r e a c h t h e s u r -f a c e o v e r a s h o r t e r d i s t a n c e , t h u s a c c o u n t i n g f o r t h e r e l a t i v e l y l o w s e t o f v a l u e s f o r mean s t i p e l e n g t h r e c o r d e d f o r D i x o n I s l a n d t h r o u g h o u t t h e y e a r . Due t o t h e f a c t t h a t d e p t h r e a d i n g s w e r e n o t t a k e n t h r o u g h -o u t t h e s p o t s a m p l i n g s t u d y i t i s n o t p o s s i b l e t o a p p l y t h e a b o v e h y p o t h e s i s t o e v e r y s i t e v i s i t e d . H o w e v e r , t h e r e a r e some o b v i o u s e x c e p t i o n s . F r o n d s c o l l e c t e d f r o m A m p h i t r i t e P o i n t , R a g l a n P o i n t a n d M a s t e r m a n I s l a n d w e r e a l l g r o w i n g a t o r n e a r t h e l o w t i d e l e v -e l and y i e l d e d l o w v a l u e s f o r mean s t i p e l e n g t h . D i s t a l M e r i s t e m a t i c R e g i o n C r i b b ( 1 9 5 3 ) h a s s u g g e s t e d t h a t t h e number o f t e r m i n a l s p l i t s -28-raay be r e l a t e d t o t h e growth r a t e o f t h e f r o n d . A c c o r d i n g t o t h i s t h e o r y a p l a n t w i t h a h i g h l e v e l o f m e r i s t e m a t i c a c t i v i t y would t e n d t o i n i t i a t e new b l a d e s more q u i c k l y t h a n t h e y c o u l d s e p a r a t e i n t o i n d i v i d u a l u n i t s . T h i s i n t e r p r e t a t i o n i s s u p p o r t e d by b o t h t h e c o n t i n u o u s sam-p l i n g s t u d y and t r a n s p l a n t s t u d y . More exposed l o c a l i t i e s were c h a r a c t e r i z e d by p l a n t s h a v i n g l a r g e r number o f t e r m i n a l s p l i t s , f a s t e r growth r a t e s o f f r o n d s and h i g h e r b l a d e i n i t i a t i o n r a t e s . As t h e growth r a t e o f i n d i v i d u a l b l a d e s does not seem t o be r e -l a t e d t o w a t e r movement th e y would t e n d t o a c c u m u l a t e d i s t a l l y on f r o n d s i n such l o c a l i t i e s . The i m p o r t a n c e o f w a t e r movement i n p r o m o t i n g t h e f o r m a t i o n o f t e r m i n a l s p l i t s , hence t h e growth o f t h e f r o n d , i s s u g g e s t e d i n d i r e c t l y by work on o t h e r members o f t h e o r d e r . For example, d i r e c t c o r r e l a t i o n between t u r b u l a n c e and t h e degree o f d i g i t a t i o n o f t h e l a m i n a i n S a c c o r h i z a , L a m i n a r i a and Hedophyllum has been d e m o n s t r a t e d by N o r t o n ( 1 9 6 9 ) , Sundene (1961a) and Widdowson (1964) r e s p e c t i v e l y . N o r t o n ( I . e . ) p o i n t s o u t t h a t t h e s e r i e s o f m e r i s t e m a t i c e v e n t s p r e c e d i n g d i g i t f o r m a t i o n i n S a c c o r h i z a p o l y -s c h i d e s a r e t h e same as t h o s e d e s c r i b e d f o r M a c r o c y s t i s p y r i f e r a . Hence i t i s not u n r e a s o n a b l e t o e x p e c t t h e s e e v e n t s t o be i n i t i a t -ed by a common s e t o f s t i m u l i . I f w a t e r movement was t h e o n l y c o n t r o l l i n g f a c t o r one would not e x p e c t t h e s e a s o n a l i t y i n d i c a t e d i n F i g u r e 8. The W i z a r d I n -l e t s i t e was s u b j e c t e d t o f a i r l y s t r o n g wave a c t i o n t h r o u g h o u t t h e y e a r , y e t d u r i n g t h e w i n t e r months was c h a r a c t e r i z e d by about t h e same mean number o f t e r m i n a l s p l i t s as t h e o t h e r l o c a l i t i e s i n t h e B a m f i e l d r e g i o n . S e a s o n a l changes i n l i g h t and t e m p e r a t u r e f o l -lowed t h e same g e n e r a l p a t t e r n as t h a t shown by t h e t e r m i n a l s p l i t s . i t i s beyond t h e scope o f t h e p r e s e n t s t u d y , however, t o c o n t e m p l a t e t h e s i g n i f i c a n c e o f t h e s e f a c t o r s r e l a t i v e t o one an--29-o t h e r . The low v a l u e s e n c o u n t e r e d a t D i x o n I s l a n d d u r i n g l a t e summer su g g e s t t h a t h i g h s u r f a c e t e m p e r a t u r e s i n c o m b i n a t i o n w i t h a low l e v e l o f w a t e r movement may have a d v e r s e l y a f f e c t e d t h e p l a n t s i n t h a t a r e a . C l e n d e n n i n g (1971) a t t r i b u t e d a l a t e summer d e c l i n e i n p h o t o s y t h e t i c c a p a c i t y o f d i s t a l b l a d e s o f Macro- c y s t i s p y r i f e r a t o h i g h s u r f a c e t e m p e r a t u r e s . Age i s a l s o i m p o r t a n t as o l d e r f r o n d s t e r m i n a t e t h e i r growth t h r o u g h a r e d u c t i o n i n t h e b l a d e i n i t i a t i o n r a t e w i t h t h e e v e n t -u a l f o r m a t i o n o f s i n g l e t e r m i n a l l a m i n a ( S c a g e l , 1948), (see a l s o F i g u r e 1 2 ) . However, t h e o n l y d i r e c t c o r r e l a t i o n between s t i p e l e n g t h and number o f t e r m i n a l s p l i t s w h i c h c o u l d be a t t r i b u t e d t o t h i s f a c t o r o c c u r r e d d u r i n g t h e W i n t e r o f 197 0. Whereas e x p o s u r e may promote t h e f o r m a t i o n o f t e r m i n a l s p l i t s i t may a t t i m e s be so s e v e r e as t o r e d u c e t h i s number by p r e -m a t u r e l y s e p a r a t i n g young b l a d e s . T h i s i s i n agreement w i t h Wom-e r s l e y (1954) who o b s e r v e d t h a t " p l a n t s g r o w i n g i n d e n s e r beds have a b r o a d e r ( t e r m i n a l ) b l a d e w i t h more segments t h a n where t h e f r o n d s a r e more exposed t o b r o k e n w a t e r . " He a l s o n o t e d a d e p t h e f f e c t but t h i s appears t o be e x p l a i n e d by t h e f a c t t h a t submerged t e r m i n a l b l a d e s would most l i k e l y be u n d e r g o i n g r a p i d growth but would not be s u b j e c t e d t o t h e f u l l f o r c e o f s u r f a c e waves-. C o n s i d e r i n g a l l o f t h e f a c t o r s w h i c h can i n f l u e n c e t h e num-ber o f t e r m i n a l s p l i t s a l o n g w i t h t h e f a c t t h a t t h e f r o n d s were c o l l e c t e d f o r t h e s p o t s a m p l i n g s t u d y a t d i f f e r e n t p e r i o d s o f t h e y e a r , t h e l a c k o f c o r r e l a t i o n t h r o u g h o u t t h i s s t u d y w i t h e x p o s u r e i s not e n t i r e l y u n e x p e c t e d . The shape o f t h e t e r m i n a l b l a d e i s a l s o h i g h l y v a r i a b l e . Those c o l l e c t e d from m o d e r a t e l y exposed t o s h e l t e r e d a r e a s were b r o a d l y f a l c a t e w i t h a l e n g t h 3 t o 5 t i m e s t h e b r e a d t h ( F i g u r e 1 3 ) . T e r m i n a l b l a d e s from exposed l o c a t i o n s were n a r r o w l y f a l c a t e and 6 t o 10 t i m e s as l o n g as b road ( F i g u r e 1 4 ) . These d e s c r i p t i o n s -30-a r e t h e same as t h o s e used by Smit h (1944) i n d e l i n e a t i n g Macro- c y s t i s i n t e g r i f o l i a and p y r i f e r a r e s p e c t i v e l y . I t i s o b v i o u s from F i g u r e 14, however, t h a t t h e t e r m i n a l b l a d e has been m o d i f i e d by t h e t e a r i n g a c t i o n on s u r f a c e waves. S m i t h ' s n o t e on l o c a l d i s -t r i b u t i o n s u g g e s t s t h a t he based h i s c o n c l u s i o n s o n l y on p l a n t s s u b j e c t e d t o t h i s s o r t o f t r e a t m e n t . The e x t e n t t o w h i c h t h e s e d i f f e r e n c e s r e p r e s e n t genuine r e s p o n s e s t o e n v i r o n m e n t a l c o n d i t -i o n s i s , t h e r f o r e , open t o q u e s t i o n . B l a d e s Number i n R e l a t i o n t o S t i p e L e n g t h A l t h o u g h t h e l i n e a r r e l a t i o n s h i p between b l a d e number and s t i p e l e n g t h was d e f i n e d f o r a l l l o c a l i t i e s i n t h e B a m f i e l d r e -g i o n t h e s l o p e and p o s i t i o n d i d n o t v a r y s i g n i f i c a n t l y w i t h i n t h e s t u d y a r e a . The number o f b l a d e s p e r u n i t l e n g t h o f s t i p e s t e a d -i l y d e c r e a s e d t h r o u g h o u t t h e l i f e o f t h e f r o n d . S i n c e f r o n d s c o l -l e c t e d t h r o u g h o u t t h e s p o t s a m p l i n g s t u d y had a c h i e v e d a h i g h l y v a r i e d l e v e l o f development t h e degree o f v a r i a t i o n o c c u r r i n g among p o p u l a t i o n s i s u n d e r s t a n d a b l e and i s n o t r e l a t e d t o w a t e r movement. Wi d t h o f Mature Laminae The r e s u l t s o f t h e two s a m p l i n g s t u d i e s s u g g e s t t h a t i n c r e a s -i n g exposure has a n a r r o w i n g e f f e c t on b l a d e w i d t h . i n F i g u r e 10 t h i s r e l a t i o n s h i p i s shown t o a p p l y t h r o u g h o u t t h e y e a r w h i l e i n T a b l e 4 i t i s seen t o a p p l y o v e r a w i d e g e o g r a p h i c a r e a . A s e a s o n a l f l u c t u a t i o n i n b l a d e w i d t h f o l l o w e d a common p a t -t e r n t h r o u g h o u t t h e s t u d y a r e a . The s i m i l a r i t y between t h i s p a t -t e r n and t h a t o f t h e number o f s p l i t s i n t h e d i s t a l m e r i s t e m a t i c r e g i o n s u g g e s t s t h e i n f l u e n c e o f a common s e t o f f a c t o r s . The o c -c u r r e n c e o f narrower b l a d e s d u r i n g w i n t e r months may be r e l a t e d t o s e a s o n a l changes i n wind d i r e c t i o n and spee d . F i g u r e 1 demon-s t r a t e s t h a t weather c o n d i t i o n s were most s e v e r e a t a l l l o c a t i o n s -31-d u r i n g t h i s p e r i o d o f t h e y e a r . On t h e o t h e r hand, d i m i s h i n g l i g h t and p o s s i b l e t e m p e r a t u r e c o n d i t i o n s may have caused t h e growth o f young b l a d e s near t h e s u r f a c e t o c e a s e b e f o r e a c h i e v -i n g maximum W i d t h . I t i s a l s o p o s s i b l e t h a t t h e f o r m a t i o n o f s m a l l e r b l a d e s i s s i m p l y a m a n i f e s t a t i o n o f an o v e r a l l s l o w i n g down o f growth p r o c e s s e s w h i c h o c c u r s a f t e r t h e f r o n d has r e a c h e d t h e s u r f a c e . A f i n a l f a c t o r w h i c h s h o u l d be t a k e n i n t o c o n s i d e r a t i o n i s t h e l e n g t h o f t h e s t i p e . N o r t h (1971) found t h a t t h e b l a d e s o f g r e a t e s t w i d t h u s u a l l y o c c u r r e d about h a l f way between t h e base and apex o f t h e f r o n d . T h i s phenomenon was o b s e r v e d many t i m e s t h r o u g h o u t t h e p r e s e n t s t u d y p a r t i c u l a r l y w i t h r e s p e c t t o o l d e r f r o n d s . T h i s s u g g e s t s t h a t one c o u l d e x p e c t an i n v e r s e r e l a t i o n -s h i p between t h e w i d t h o f youngest mature b l a d e s and t h e l e n g t h o f t h e s t i p e t o a p p l y t o f r o n d s w h i c h had p a s s e d t h e h a l f - w a y p o i n t i n t h e i r g r o w t h . A c o m p a r i s o n o f F i g u r e s 6 and 10 s u g g e s t s t h a t t h i s r e l a t i o n s h i p may e x p l a i n some o f t h e o b s e r v e d f l u c t -u a t i o n i n b l a d e w i d t h . On t h e b a s i s o f comparisons between b l a d e s o c c u p y i n g t h e same p o s i t i o n on d i f f e r e n t f r o n d s t h e r e s u l t s o f t h e t r a n s p l a n t s t u d y s u g g e s t t h e p r e s e n c e o f a h i g h l e v e l o f e n v i r o n m e n t a l c o n -t r o l o v e r l a m i n a w i d t h . The a b i l i t y o f t h e p l a n t t o r e s p o n d i n t h i s manner may, under exposed c o n d i t i o n s , c o n f l i c t w i t h i t s a b i l -i t y t o produce a maximum s u r f a c e a r e a f o r p h o t o s y n t h e t i c a c t i v i t y . However, i n c r e a s e d exposure was a l s o c h a r a c t e r i z e d by t h e form-a t i o n o f more h i g h l y c o r r u g a t e d o r r u g o s e s u r f a c e s . T h i s appears t o meet t h e p l a n t ' s p h o t o s y n t h e t i c needs w h i l e k e e p i n g r e s i s t a n c e t o w a t e r movement t o a minimum. Calm forms were u s u a l l y c o m p l e t e -l y l a c k i n g i n t h i s f e a t u r e . I n t h i s r e s p e c t t h e t y p e o f w a t e r movement may a l s o f i g u r e s i g n i f i c a n t l y . A l t h o u g h f r o n d s c o l l e c t e d from Browning Passage were s i m i l a r i n appearance t o t h o s e c o l l e c t e d -32-from t h e most exposed s i t e s many o f t h e b l a d e s had c o m p l e t e l y smooth s u r f a c e s . T h i s may be r e l a t e d t o t h e f a c t t h a t , as i n B a m f i e l d I n l e t , t i d a l c u r r e n t s appeared t o c o n s t i t u t e t h e major form o f w a t e r movement. A d e p t h e f f e c t was a l s o o b s e r v e d as b l a d e s f u r t h e r removed from t h e i n f l u e n c e o f s u r f a c e wave a c t i o n were g e n e r a l l y l e s s r u g o s e . I n s h e l t e r e d w a t e r s t h e f o r m a t i o n o f w i d e r b l a d e s would not o n l y p r o v i d e a l a r g e s u r f a c e a r e a f o r p h o t o s y n t h e t i c a c t i v i t y b u t would a l s o i n c r e a s e r e s i s t a n c e t o w a t e r movement. T h i s may f u r -t h e r i n c r e a s e t h e amount o f l i g h t r e a c h i n g t h e s u r f a c e o f t h e b l a d e s by c a u s i n g t h e laminae t o assume a p a r a l l e l p o s i t i o n r e l -a t i v e t o t h e s u r f a c e o f t h e w a t e r . N o r t o n (1969) has s u g g e s t e d two p o s s i b l e mechanisms by w h i c h t u r b u l e n c e may c o n t r o l b l a d e w i d t h . R a p i d w a t e r movement may a c t d i r e c t l y upon th e m e r i s t e m a t i c zone t h r o u g h t h e c r e a t i o n o f t e n -s i o n a l o n g t h e s u r f a c e o f t h e b l a d e , o r i n d i r e c t l y t h r o u g h i t s i n -f l u e n c e on the p h y s i o l o g y o f a c t i v e l y d i v i d i n g c e l l . The l a t t e r p o s s i b i l i t y may e x p l a i n the growth o f n a r r o w - b l a d e d forms o f A l a r i a  e s c u l e n t a i n a l a b o r a t o r y c u l t u r e system b y S o u t h (1970). As he used a c o n t i n u o u s l y f l o w i n g system i t i s p o s s i b l e t h a t t h e r e was s u f f i c i e n t w a t e r c i r c u l a t i o n o f e l i c i t t h e o b s e r v e d r e s p o n s e . The, shape o f t h e base o f t h e b l a d e v a r i e d c o n s i d e r a b l y and i n a f a s h i o n s i m i l a r t o t h a t d e s c r i b e d by P a r k e (1948). She a t t r i b -u t e d t h e s e v a r i a t i o n s t o d i f f e r e n c e s i n t h e growth r a t e s and de-s c r i b e d t h r e e main forms: a f a s t g r o w i n g f u s i f o r m t y p e , a s l o w e r g r o w i n g cuneate t y p e and v e r y slow g r o w i n g s e m i c i r c u l a r o r sub-c o r d a t e t y p e . These forms were f o u n d t h r o u g h o u t t h e p r e s e n t s t u d y b u t t h e i r o c c u r r e n c e appeared t o be more c l o s e l y r e l a t e d t o e x -posure as t h e r e was found t o be no s i g n i f i c a n t d i f f e r e n c e i n t h e growth r a t e s o f b l a d e s a t the same d e p t h f r o m one l o c a l i t y t o an -33-o t h e r . Examples o f t h e t h r e e forms a r e shown i n F i g u r e 15, 16, and 17. Exposure a l s o p l a y s an i m p o r t a n t r o l e i n t h e d e t e r m i n a t i o n o f b l a d e l e n g t h by p r o m o t i n g d e t e r i o r a t i o n o f t h e d i s t a l p o r t i o n s . Young laminae a r e a b l e t o c o u n t e r a c t t h i s t h r o u g h a h i g h r a t e o f p r o d u c t i o n o f new t i s s u e . However, e r o s i o n c o n t i n u e s a f t e r growth c e a s e s and t h i s u s u a l l y r e s u l t s i n t h e complete l o s s o f o l d e r l a m i n a e . I n B a m f i e l d I n l e t t h e n a t u r e o f t h e wa t e r m o t i o n was su c h t h a t decay was n o t promoted. T h i s r e s u l t e d i n t h e f o r m a t i o n o f u n u s u a l l y l o n g l a m i n a e w h i c h o c c u p i e d much o f t h e s t i p e . G r a z e r s and e p i p h y t e s a re a l s o c o n s i d e r e d t o p l a y i n i m p o r t -a n t r o l e i n the d e t e r m i n a t i o n o f b l a d e l e n g t h i n more exposed l o -c a l i t i e s . On the o t h e r hand, m i c r o b i a l decay may have been t h e major f a c t o r r e s p o n s i b l e f o r t h e s h o r t l e n g t h o f t h e lami n a e on p l a n t s c o l l e c t e d from D i x o n I s l a n d . Lamina T h i c k n e s s A c o n s i d e r a t i o n o f o n l y t h e o l d e r l a m i n a e c o l l e c t e d t h r o u g h -out t h e c o n t i n u o u s s a m p l i n g s t u d y s u g g e s t s t h a t b l a d e t h i c k n e s s i n c r e a s e s w i t h e x p o s u r e . T h i s i s f u r t h e r e x e m p l i f i e d by t h e r e -s u l t s o f t h e s p o t s a m p l i n g s t u d y and a g r e e s w i t h t h e f i n d i n g s o f N o r t o n ( I . e . ) . There appear t o be two d i s t i n c t c a t e g o r i e s : a t h i c k , t ough o u t e r c o a s t form d e m o n s t r a t e d b y p l a n t s from Amphi-t r i t e P o i n t , Browning Passage, Hope I s l a n d and Warren I s l a n d and a t h i n n e r , more d e l i c a t e form c h a r a c t e r i s t i c o f t h e r e m a i n i n g l o c -a l i t i e s . W h i l e t h e r e was c o n s i d e r a b l e v a r i a t i o n w i t h i n each form, t h e r e was a complete absence o f i n t e r m e d i a t e v a l u e s o v e r a range o f about 7 m i c r o n s . A l t h o u g h t h e c o r t e x : m e d u l l a r a t i o d i d not v a r y s i g n i f i c a n t l y w i t h e x p o s u r e , t h e c o r r e s p o n d i n g d i f f e r e n c e s i n t h e t h i c k n e s s o f c o r t i c a l t i s s u e may have been p a r t i a l l y r e s p o n s i b l e f o r t h e ob-s e r v e d v a r i a t i o n i n t e x t u r e . - 3 4 -S p i n e s The r e s u l t s o f t h e c o n t i n u o u s s a m p l i n g s t u d y s u g g e s t an i n -v e r s e r e l a t i o n s h i p between s p i n e l e n g t h and e x p osure b u t t h i s i s n o t s u b s t a n t i a t e d by t h e s p o t s a m p l i n g s t u d y . A l t h o u g h t h e s p i n e s were, a t t i m e s , much r e d u c e d i n l e n g t h o r w i d e l y s p a c e d , under-no c o n d i t i o n s were t h e y found t o be e n t i r e l y absent from s t e r i l e l a m i n a e . The p o s i t i o n o f t h e s p i n e s r e l a t i v e t o the edge o f t h e b l a d e does appear t o v a r y i n a f i x e d p a t t e r n . Under exposed c o n d i t i o n s t h e s p i n e s t e n d t o l i e c l o s e t o t h e edge o f t h e b l a d e ( F i g u r e 1 8 ) , p o s s i b l y as a means o f r e d u c i n g f r i c t i o n . On t h e o t h e r hand, i n s h e l t e r e d l o c a l i t i e s t h e y t e n d t o p r o j e c t o u t w a r d , o f t e n f o r m i n g an a n g l e o f 90 d e g r e e s ( F i g u r e 1 9 ) . I n t h i s case t h e e f f e c t w o uld be t o i n c r e a s e f r i c t i o n , t h e r e b y c r e a t i n g as much d r a g as p o s s i b l e a l o n g t h e edge o f the b l a d e . The p o s s i b l e b e n e f i t o f i n -c r e a s i n g d r a g t o t h e p l a n t has a l r e a d y been d i s c u s s e d i n t h e s e c t -i o n on l a m i n a w i d t h . S i m i l a r o b s e r v a t i o n s on t h e p o s i t i o n o f t h e s p i n e s o f M a c r o c y s t i s p y r i f e r a were made by B r a n d t (1923). Pneumatocysts As i n t h e case o f b l a d e t h i c k n e s s , the pneumatocysts seem t o be d i s t i n g u i s h e d by an o u t e r and i n n e r . c o a s t form. S k o t t s b e r g (1907) found t h e pneumatocysts from t h e most exposed l o c a l i t i e s t o be o f such l a r g e d i m e n s i o n s as t o w a r r a n t the use o f the s p e c -i a l d e s c r i p t i v e term " l o n g i b u l l a t a " . T h i s term would a p p l y e q u a l l y w e l l t o l o c a l p l a n t s from the o u t e r c o a s t . The o c c u r r e n c e o f s m a l l e r pneumatocysts a t A m p h i t r i t e P o i n t i s a t t r i b u t e d t o t h e im-mature s t a t u s o f t h e sample b l a d e s . S k o t t s b e r g a l s o d e s c r i b e d a s h o r t , w i d e , p y r i f o r m type c h a r a c t e r i s t i c o f l e s s exposed s i t e s . S i m i l a r forms were o c c a s i o n a l l y o b s e r v e d t h r o u g h o u t t h e s p o t samp-l i n g s t u d y u s u a l l y a t l o c a l i t i e s d e s c r i b e d as m o d e r a t e l y exposed. G e n e r a l l y the i n n e r c o a s t forms were v e r y s i m i l a r i n appearance t o -35- -o u t e r c o a s t forms and d i f f e r e d o n l y i n o v e r a l l s i z e . The d i m e n s i o n s o f t h e pneumatocysts v a r i e d t h r o u g h o u t t h e e n -t i r e range o f e x p osure i n such a way as t o s u g g e s t t h a t d e c r e a s i n g e x p o sure has a r e d u c i n g e f f e c t . However, w i t h p a r t i c u l a r r e -g a r d t o l e n g t h t h i s v a r i a t i o n was not as c o n s i s t e n t as some o f t h e o t h e r f e a t u r e s c o n s i d e r e d . The o c c u r r e n c e o f s t r o n g e r dynamic f o r c e s a l o n g w i t h t h e g r e a t e r t h i c k n e s s o f t h e l a m i n a i n more ex p o s e d a r e a s may be r e -l a t e d t o t h e f o r m a t i o n o f pneumatocysts o f l a r g e r c a p a c i t y as b o t h t h e s e f a c t o r s w o u l d t e n d t o draw the f r o n d s away from t h e s u r f a c e . The g r e a t e r i n f l u e n c e o f wave a c t i o n n e a r t h e s u r f a c e may have been r e s p o n s i b l e f o r t h e o c c u r r e n c e o f l a r g e r pneumatocysts a t t h e 3/4 p o s i t i o n a t a l l l o c a l i t i e s i n t h e B a m f i e l d r e g i o n e x -c e p t W i z a r d I s l e t . The v e r y s m a l l pneumatocysts o b s e r v e d a t D i x o n I s l a n d seem t o r e p r e s e n t an anomalous s i t u a t i o n c h a r a c t e r i s t i c o f o n l y the most s h e l t e r e d w a t e r s . S i m i l a r pneumatocysts ha.ve been d e s c r i b e d f o r l o o s e l y i n g p o p u l a t i o n s o f M a c r o c y s t i s p y r i f e r a (Moore, 1962). L i n d a u e r , Chapman and A i k e n (1961) r e p o r t e d a c omplete absence o f b l a d d e r s on p l a n t s g r o w i n g under s i m i l a r c o n d i t i o n s . QUALITATIVE OBSERVATIONS H o l d f a s t The morphology o f t h e h o l d f a s t was g e n e r a l l y u n i f o r m o v e r a wide range o f e x p o s u r e s w i t h one n o t a b l e e x c e p t i o n . I n s t e a d o f b e i n g c l o s e l y a d h e r e n t t o t h e s u b s t r a t e t h e r h i z o m a t o u s p o r t i o n s o f t h e h o l d f a s t s o f p l a n t s g r o w i n g i n B a m f i e l d I n l e t appeared t o l o s e t h e i r p o l a r i t y and gave r i s e t o a compact network o f l o n g , narrow d e s c e n d i n g h a p t e r a . T h i s r e s u l t e d i n t h e f o r m a t i o n o f a b e e - h i v e shaped h o l d f a s t , the c e n t e r o f w h i c h was o f t e n c o m p l e t e l y decayed o r e a t e n away. N e u s h u l (1971) r e p o r t e d a l o s s o f g e o t r o p i s m i n t h e h o l d f a s t -36-o f M a c r o c y s t i s p y r i f e r a b u t a t t r i b u t e d t h i s t o t h e i n f l u e n c e o f warm w a t e r . T h i s e x p l a n a t i o n does not appear t o a p p l y i n t h e p r e s e n t s i t u a t i o n as even t h e : o l d e s t h o l d f a s t s a t . o t h e r s i t e s i n t h e B a m f i e l d r e g i o n remained c l o s e l y a d h e r e n t t o t h e s u b s t r a t e . P a r k e ' s ( I . e . ) s u g g e s t i o n o f a s u b s t r a t e e f f e c t a l s o does not seem t o a p p l y as most o f t h e p l a n t s i n B a m f i e l d I n l e t were g r o w i n g on s o l i d o r b r o k e n b e d r o c k . Why t h e p l a n t s s h o u l d r e s p o n d i n t h i s way r emains v e r y much a m y s t e r y . O t h e r l a m i n a r i a l e a n s g r o w i n g i n B a m f i e l d I n l e t r e -sponded i n a s i m i l a r manner, o f t e n f o r m i n g l a r g e h o l d f a s t s w h i c h were v e r y p o o r l y a t t a c h e d . I t i s p o s s i b l e t h a t t h e p l a n t does not become f i r m l y a t t a c h e d t o t h e s u b s t r a t e because t o do so would c o n s t i t u t e an u n n e c e s s a r y e x p e n d i t u r e o f e n e r g y w h i c h c o u l d o t h e r -w i s e be d i v e r t e d t o s t o r a g e p r o c e s s e s i n t h e h a p t e r a . A l a r g e , d e n s e l y packed h o l d f a s t c o u l d a l s o s e r v e an a n c h o r i n g f u n c t i o n f o r a p l a n t w h i c h i s g r o w i n g i n v e r y s h e l t e r e d w a t e r s . S p o r o p h y l l s C e r t a i n a s p e c t s o f t h e morphology o f t h e s p o r o p h y l l s t e n d e d t o v a r y g r e a t l y w i t h i n and among l o c a l i t i e s . W h i l e e n v i r o n m e n t a l f a c t o r s may have had a m o d i f y i n g e f f e c t , t h e n a t u r e o f t h i s v a r i -a t i o n appeared t o be more c l o s e l y r e l a t e d t o the n a t u r e o f t h e i r p r e c u r s o r s . Those s p o r o p h y l l s w h i c h o c c u p i e d t h e most p r o x i m a l p o s i t i o n s on t h e s t i p e were e i t h e r d e r i v e d from th e f i r s t l a m i n a t o s e p a r a t e from t h e young f r o n d o r from a b a s a l m e r i s t e m w h i c h f a i l e d t o g i v e r i s e t o a new l a t e r a l . As s u c h , t h e s e s p o r o p h y l l s g e n e r a l l y l a c k e d pneumatocysts and were u s u a l l y h i g h l y r a m i f i e d . N e u s h u l (1962) p o i n t e d out t h a t t h e o r i g i n o f t h e s p o r o p h y l l s was a l s o r e f l e c t e d i n t h e b r a n c h i n g p a t t e r n , b e i n g s y m m e t r i c a l i n t h e former case and a s y m m e t r i c a l i n t h e l a t t e r . S p o r o p h y l l s f u r t h e r removed from t h e base o f the p l a n t r e s e m b l e d more c l o s e l y t h e s t e r i l e l a m i n a e . -37-Pneumatocysts and s p i n e s were u s u a l l y p r e s e n t and b r a n c h i n g b e -came l e s s p r e v a l e n t w i t h i n c r e a s e d d i s t a n c e from th e h o l d f a s t . These s p o r o p h y l l s tended t o show t h e same g e n e r a l r e s p o n s e s t o e x p o sure c o n d i t i o n s as have a l r e a d y been d e s c r i b e d . THE ENTIRE PLANT T h i s s t u d y has c l e a r l y d e m o n s t r a t e d t h e wide range o f mor-p h o l o g i e s w h i c h e n a b l e t h e p l a n t t o occupy many o f t h e v a r i e d h a b i t a t s c h a r a c t e r i s t i c o f l o c a l w a t e r s . I n many ways t h e n a t u r e o f t h e r e l a t i o n s h i p between form and e n v i r o n m e n t has been shown t o comply w i t h t h e g e n e r a l p a t t e r n a l r e a d y e s t a b l i s h e d t h r o u g h o u t t h e o r d e r . The r e s u l t s o f t h e t r a n s p l a n t s t u d y s u g g e s t t h a t t h e mechan-ism o f m o r p h o l o g i c a l a d a p t a t i o n i n t h e B a m f i e l d r e g i o n i s p h e n o t y -p i c p l a s t i c i t y . The a p p a r e n t a b i l i t y o f t h e p l a n t s t o r e s p o n d t o s e a s o n a l f l u c t u a t i o n s i n dynamic c o n d i t i o n s w i t h i n a l o c a l i t y and a l s o w i t h i n i n d i v i d u a l f r o n d s s u p p o r t s t h i s c o n c l u s i o n . Whether p h e n o t y p i c p l a s t i c i t y i s s o l e l y r e s p o n s i b l e f o r t h e e n t i r e range o f m o r p h o l o g i e s w h i c h were o b s e r v e d i s s t i l l v e r y much open t o q u e s t i o n . The forms found g r o w i n g on t h e o u t e r c o a s t were, i n some r e s p e c t s , so s t r i k i n g l y d i f f e r e n t from i n n e r c o a s t forms as t o s uggest t h e p r e s e n c e o f a t l e a s t two c a t e g o r i e s o f gene p o o l s . N o r t h (1969) has d e m o n s t r a t e d t h a t t h e m a j o r i t y o f t h e s p o r e s w h i c h a r e l i b e r a t e d from a mature s p o r o p h y t e p r o b a b l y complete t h e l i f e c y c l e w i t h i n a s h o r t d i s t a n c e o f t h e p a r e n t . T h e r e f o r e , i t i s q u i t e p o s s i b l e t h a t t h e two forms have r e s u l t e d t h r o u g h c o n t i n u o u s i n b r e e d i n g w h i l e t h e p o t e n t i a l f o r a h i g h degree o f polymorphism has been m a i n t a i n e d . T h i s w o u l d c o n t i n u e t o be e s s e n t i a l i n an environment where dynamic c o n d i t i o n s can v a r y s i g -n i f i c a n t l y o v e r a v e r y s h o r t d i s t a n c e . Whether g e n e t i c i s o l a t i o n has r e s u l t e d i n t h e e s t a b l i s h m e n t o f s e p a r a t e s p e c i e s or v a r i t i e s has' y e t t o be d e m o n s t r a t e d . - 3 8 -SUMMARY S e v e r a l a s p e c t s o f the h a b i t o f M a c r o c y s t i s i n t e g r i f o l i a B o r y have p r o v e n t o be h i g h l y v a r i a b l e . The o v e r a l l morphology o f t h e p l a n t i s r e l a t e d t o t h e n a t u r e and e x t e n t o f w a t e r movement t o w h i c h i t i s s u b j e c t e d t h r o u g h o u t i t s development. Under exposed c o n d i t i o n s the p l a n t must assume a form w h i c h w i l l e n a b l e i t t o w i t h s t a n d t h e s t r e s s e s c r e a t e d by r a p i d w a t e r movement. Thus., p l a n t s g r o w i n g i n such a r e a s a r e c h a r a c t e r i z e d by: s t i p e s o f l a r g e d i a m e t e r , narrow, t h i c k , tough laminae w h i c h a r e cuneate a t t h e b a s e , . s p i n e s s e t c l o s e t o t h e m a r g i n s o f t h e l a m i n a e , l a r g e , t a p e r i n g p n e u m a t o c y s t s , h o l d f a s t s w h i c h a r e c l o s e l y a d h e r e n t t o t h e s u b s t r a t e and b e a r s h o r t , wide h a p t e r a . As the h o r i z o n t a l component o f w a t e r movement t e n d s t o draw t h e f r o n d s away from t h e s u r f a c e , p l a n t s s u b j e c t e d t o b r o k e n w a t e r o r s t r o n g t i d a l c u r r e n t s r e q u i r e pneumatocysts o f l a r g e r c a p a c i t y . The i n c l i n a t i o n o f t h e f r o n d s a l s o n e c e s s i t a t e s the f o r m a t i o n o f l o n g e r s t i p e s t h a n w o u l d be r e q u i r e d by p l a n t s g r o w i n g a t t h e same d e p t h i n s h e l t e r e d w a t e r s . T h i s i s compensated by a h i g h e r r a t e „ o f s t i p e e l o n g a t i o n t h r o u g h o u t t h e e x p o n e n t i a l phase o f g r o w t h . R a p i d w a t e r movement a l s o s t i m u l a t e s b l a d e i n i t i a t i o n . Hence t h e number of segments i n the t e r m i n a l l a m i n a may p r o v i d e an i n -dex o f t h e d e v e l o p m e n t a l irate o f t h e p l a n t , p a r t i c u l a r l y as t h e e l o n g a t i o n o f i n d i v i d u a l l aminae does not appear t o be a f u n c t i o n o f e x p o s u r e . However, as t h e form o f t h e t e r m a i n a l l a m i n a can a l s o be i n f l u e n c e d c o n s i d e r a b l y by t h e damaging e f f e c t s o f b r o k e n w a t e r and by t h e age o f t h e f r o n d , t h i s f e a t u r e i s n o t c o n s i d e r e d t o be a r e l i a b l e i n d i c a t o r o f dynamic c o n d i t i o n s . The laminae o f p l a n t s from exposed s i t e s a l s o t e n d t o be more h i g h l y r u g o s e . T h i s appears t o s e r v e t h e f u n c t i o n o f p r o v i d i n g a -39-l a r g e s u r f a c e a r e a f o r l i g h t a b s o r b t i o n w i t h o u t g r e a t l y i n c r e a s -i n g r e s i s t a n c e t o w a t e r movement. I n s h e l t e r e d w a t e r s t h e r e i s l e s s emphasis on s t r e s s and f r i c t i o n . Thus p l a n t s g r o w i n g under t h e s e c o n d i t i o n s have: narrow s t i p e s / w i d e , t h i n , d e l i c a t e laminae w h i c h a r e c u c u l a t e a t t h e b a s e , outward p r o j e c t i n g s p i n e s , s m a l l , o f t e n g l o b u l a r p n e u m a t o c y s t s , h o l d f a s t s w h i c h are not c l o s e l y a d h e r r e n t t o t h e s u b s t r a t e and b e a r l o n g narrow h a p t e r a . B e s i d e s p r o v i d i n g a l a r g e s u r f a c e a r e a f o r l i g h t a b s o r b t i o n t h e o v e r a l l morphology o f t h e l a m i n a e may a l s o enchance p h o t o -s y n t h e i s by e n a b l i n g them t o t a k e a d v a n t a g e o f m i l d c u r r e n t f l o w s i n assuming a h o r i z o n t a l p o s i t i o n i n t h e w a t e r column. The l e n g t h o f t h e mature lam i n a e i s a f u n c t i o n o f s e v e r a l f a c t o r s i n a d d i t i o n t o w a t e r movement. Tlaese i n c l u d e t i s s u e s t r e n g t h , g r a z i n g p r e s s u r e , e p i p h y t e s , m i c r o b i a l a c t i v i t y and age. Thus, i t i s not p o s s i b l e do draw f i r m c o n c l u s i o n s r e g a r d i n g t h e e f f e c t s o f wateymovement w i t h o u t g r e a t l y r e d u c i n g t h e number o f v a r i a b l e s . W h i l e t h e s p o r o p h l l s t e n d g e n e r a l l y t o r e f l e c t dynamic c o n -d i t i o n s i n much the same way as s t e r i l e l a m i n a e t h e i r morphology i s a l s o i n f l u e n d e d t o a l a r g e e x t e n t by t h e n a t u r e o f t h e i r p r e -c u r s o r s . A wide range o f i n t e r m e d i a t e forms have been d e s c r i b e d from s i t e s s u b j e c t e d t o l e s s extreme c o n d i t i o n s - The r e s u l t s o f a t r a n s p l a n t s t u d y , s e a s o n a l f l u c t u a t i o n s w i t h i n p o p u l a t i o n s and v a r i a t i o n s w i t h i n p l a n t s s u g g e s t t h a t t h e mechanism o f r e s p o n s e i s p h e n o t y p i c p l a s t i c i t y . However, some a s p e c t s o f t h e p l a n t s ob-s e r v e d a t t h e exposed or o u t e r c o a s t s i t e s s u g g e s t t h a t t h e y may be g e n e t i c a l l y d i s t i n c t from i n n e r c o a s t f o r m s . The most c o n -s i s t e n t f e a t u r e upon w h i c h a taxonomic s e p a r a t i o n m ight be b ased -40-i s lamina thickness. Further studies in v o l v i n g the two forms are recommended before such a step i s taken. F i g u r e 1. Measurements o f w i n d d i r e c t i o n and speed (m.p.h.) t a k e n t h r o u g h o u t 1970 a t Cape B e a l e a t t h e s o u t h -e a s t e n t r a n c e t o B a r k e l e y Sound. Three r e c o r d i n g s were t a k e n d a i l y a t 0700, 1200 and 2000 h o u r s . Wind speed i s i n d i c a t e d as f o l l o w s : - I I ...1 - 10; ES 11 - 20; above 20. (These d a t a were p r o v i d e d by t h e Government o f Canada, M e t e o r l o g i c a l S e r v i c e ) . Number of Readings - K9 <* — •* — - I* . C* * Ol — 10 U » o o o o O O O O O O O O O - o F i g u r e 2a. C o a s t o f B r i t i s h Columbia and Southern A l a s k a showing s i t e s v i s i t e d throughout the s p o t s a m p l i n g s t u d y . gure 2b. Sites v i s i t e d throughout the continuous sampling study. Figure 3. Near-surface t e m p e r a t u r e / s a l i n i t y diagrams based on measure-ments taken at the four Bamfield s i t e s throughout August, 1970. Depth readings are i n meters. Salinity foo) 2 9 3 0 31 32 33 ~i—i—i—i—r 16 15 o 14 O * 13 Z3 i i 2 | « " . o l 3/8/70 29 3 0 31 3 2 3 3 " i — i — i — i — T ie 15 14 13 12. II 101 16 15 14 13 12 it 10 29 30 31 32 33 ~ i — I I I — r 3/8/70 29 30 31 32 33 16 15 14 13 12 II 10 20/8/70 1—I—i—r T 8 . B . V 16 15 14 13 12 II 10 16 15 14 13 12 II 10 20/8/70 3 2 5 2 0 or 3 . 5 -< or LU Q_ 10 LU P 5 -35 oo > 30 z 25 - 20 S? N M A M MONTH Figure 4. v a r i a t i o n with time of s a l i n i t y at one meter and temperature at one meter ( ) and f i v e meters ( ) i n Bamfield Inlet through 1969-70. (Provided i n part by the Bamfield Marine Station) -46-F igure 5 . The Wizard I s l e t t r a n s p l a n t s i t e f o l l o w i n g the e x p e r i m e n t . A t r a n s p l a n t stone b e a r i n g the s i l i r u b b e r s t r i p s remains cemented i n - p l a c e i n the f o r e g r o u n d . Figure 6. V a r i a t i o n w i t h time of mean s t i p e diameter and length at the four continuous sampling s i t e s throughout 1970. Maximum and minimum values are i n d i c a t e d by the h o r i z o n t a l b a r s . 3 3 -9 W. I. . 8 STIPE DIAMETER (mm.) S A M P L E S I Z E 2 6 2 3 12 II 10 9 8 7 6 5 4 3 2 I 10 9 8 7 ~ 6 E I 5 cn £ ^ -j • 3 o. OT 2 _ S.B. R = 0.4 8 97 W. -48-12 11 — 10 9 8 7 6 5 4 3 2 J I I I I I L 5 6 7 8 R--0.61 2 2 _ D.I. J I L J l _ L 2 3 4 5 6 7 Stipe Diameter (mm.) J 9 B.I. R = 0.67 00 I I I I I I I I I R = 0.0404 J I I I I I I 1 1 F i g u r e 7. Recorded v a l u e s of s t i p e d i a meter and l e n g t h f o r f r o n d s c o l l e c t e d throughout the c o n t i n u o u s s a m p l i n g s t u d y . A l i n e a r r e l a t i o n s h i p i s expressed g r a p h i c a l l y f o r t h r e e of the sampling s i t e s . The s i g n i f i c a n c e o f the term "R" i s e x p l a i n e d i n the RESULTS. Figure 8. V a r i a t i o n w i t h time of the mean number of t e r m i n a l s p l i t s on fronds c o l l e c t e d throughout the continuous sampling study. A Wizard I s l e t , • Scott's Bay, O Bamfield I n l e t , • Dixon I s l a n d . Maximum and minimum values are i n d i c a t e d by h o r i z o n t a l b a r s . -50-II 10 9 8 7 6 5 4 3 • 2 I 9 6 7 6 5 4 3 _ W.I R • 0.5 536 1 2 3 4 S.B. R« 0.6619 J I L - B.I. n 10 9 8 7 5 -4 — 3 — 2 — I -J I I I I I I I I I 5 6 7 6 9 10 _ D.I. J I I 1 2 3 4 5 6 7 8 9 1 0 Number of L am inae (xlO) R- 0.74 99 J I 1 I 2 3 4 5 6 7 8 9 10 R- 0.6350 J I I I I I I L 2 3 4 5 6 7 8 9 10 F i g u r e 9. Recorded v a l u e s o f b l a d e number and s t i p e l e n g t h f o r f r o n d s c o l l e c t e d throughout the c o n t i n u o u s s a m p l i n g s t u d y . A l i n e a r r e l a t i o n s h i p i s e x p r e s s e d . g r a p h i c a l l y f o r a l l s i t e s . The s i g n i f i c a n c e of the term "R" i s e x p l a i n e d i n the RESULTS. -51-301— 20 o .£10 E o c o J | F | M | A | M | J | J | A | S | 0 [ N | D Month F i g u r e 10. V a r i a t i o n w i t h t i n e o f the mean w i d t h o f young, mature laminae on f r o n d s c o l l e c t e d t h r o u ghout the c o n t i n u o u s s a m p l i n g s t u d y . Legend i s g i v e n i n F i g u r e 8. •52-r Figure 12. Transplant study. Growth i n length of primary fronds. • Wizard I s l e t , B Scott's Bay, G Bamfield I n l e t , • Dixon I s l a n d . Month F i g u r e 12. Continued -55-jTjTjTjj i'yi'i'i'|'ir|j|ii|iM'|'i'i,g'i'ii,|,i,i'vj|'|li''lp'rj; ,1 I € I M II 01 * I . » . » i l I • Figure 13. A distal meristematic region of a plant from Wizard Islet. Note the bladder which is beginning to form at the apex of the stipe. Figure 14. A distal meristematic region of a plant from Hope Island. I Figures 1 5 , 1 6 , 17. Basal portions of blades c o l l e c t e d during the sampling studies. The exposure categories are (from l e f t to r i g h t ) : moderately s h e l t e r e d , moderately exposed, exposed. 'fT^H'SI rijj iiri'|'i |i iij| |tTiT |Tjj ' |Ti ,| |iTg'iTi ||'iT|; 467 «|llll|llllfjll|lll^  9lktilrf(MiRilililihlibffilrfililililiffiiltblihlil>RilililihlilXli!^ililil<l Figures 18 , 19. Margins of laminae from an exposed (18) and moderately exposed (19) s i t e . Note the outward p r o j e c t i o n of the spines on the lamina from the less exposed s i t e . Chart Location Number (Spot Sampling Study) 1 Date Coordinates Open Fetch (n.m.) Exposure Comments Angle Max. Min. Category 2 3 4 Raglan Point, 10/04/70 N: 50 52* Balaklava I s . W:127038.1' N i l Amphitrite Point Masterman Island Hope Island Hope Island Browning Passage Port Hardy 50/04/70 N: 55°23' 180C W:125°32.52' 12/09/70 N: 50°45.4' 80 £ W:127°25.2' 14/09/70 N: 50°55.2« 125C W:127°59.5' 14/09/70 N: 50°54.3' 180C W:127°59.1 f 16/09/70 N: 50°51.35' V/:127°38.25' 16/09/70 N: 49°43.3' 22C W:127 29.151 Unlimited 28.0 12.0 M.E. M.S. In a small cove, sheltered from the direct force of onshore winds. E. Plants growing at about zero tide l e v e l i n a surge channel. Unl. 18 E. Protected only by an offshore bed of Nereocystis 2.8 2.8 E. In a sl i g h t indentation of the shoreline. Subjected to large waves from the northwest. S l i g h t l y less exposed than (4). - - - - E. Subjected to unimpeded waves t r a v e l l i n g along Browning Pas-sage and to strong t i d a l flows. 12.0 12.0 S. Probably sheltered during sum-mer months, becoming moderately exposed throughout winter due to prevailing n o r t h e r l i e s . Table 1. Sites v i s i t e d throughout the Spot Sampling and Continuous Sampling studies'. Exposure terms are: E - exposed, S - sheltered, M - moderately. Petch i s given i n n a u t i c a l miles. The term "open angle" describes the angle through which the s i t e i s subjected to onshore waves Chart Location Number 8 Deer Island Date Coordinates Open Fetch (n.m.) Exposure Comments Angle Max. Min. Category 17/09/70 N: 50°43.3' 70° 12.0 12.0 M.E. W:127 23.0' 9 Warren Island I4/01/7I N: 55°52'59" 25° 8.0 8.0 M.E.-E. W:133~51'15" 10 Cape Daphne 18/01/71 N: 50°44.65'170C W:127°26.9' (Continuous Sampling Study) Wizard Island • Scott's Bay Bamfield I n l e t Dixon Island — - - N: 50°51.46'120° W:125° 9.4' - - N: 48°50.15»120° W:125 8.6' - - N: 48°50.1« 38° W:125° 8.1' - - N: 48°51.25,110° W:125 6.95' 7.0 2.7 7.6 2.8 3.7 Force of waves somewhat dampened by an offshore series of emerged rocks. Macrocystis found only along the north aide of Warren Cove. Rip-pling of the sand at about 40 feet suggests the occurrence of heavy surface wave action. 0.7 M.E. 1.3 M.E. 1.1 M.S. 2.2 S. 0.6 S.-M.E. Table 1. Continued. -59-Month Sample Size Variance Proba-Fronds per S i t e Laminae per Frond Ratio F b i l i t y A p r i l 3 2 15.32 0.0032 May 4 4 6.46 0.0126 June 4 4 7.29 0.0087 J u l y 4 4 6.21 0.0141 August 3 3 2.56 0.1502 October 3 3 2.62 0.1450 December 3 5 1.10 0.4162 Table 2. A n a l y s i s of variance among the four continuous sampling s i t e s f o r width of young mature laminae. The term "Variance R a t i o " i s explained i n the RESULTS. P r o b a b i l i t y values are f o r common means. Table 3. A n a l y s i s of data obtained from sample blades which were c o l -l e c t e d i n the Bamfield r e g i o n during A p r i l , May and June of 1970. Variance r a t i o s and p r o b a b i l i t y t a b l e s apply o n l y to , blades obtained half-way along the s t i p e from the h o l d f a s t . Feature Location P o s i t i o n on Frond Mean Max. Min. Lamina Wizard 1/2 367, 433 264 Thickness I s l e t 3/4 314 401 249 (u) Scott's 1/2 327 390 242 Bay 3/4 328 409 240 Bamfield 1/2 309 351 244 I n l e t 3/4 329 381 263 Dixon 1/3 323 367 281 I s l a n d 3/4 286 349 224 Cortexs W.I. 1/2 2.45 3.58 1.76 Medulla 3/4 2.71 5.05 0.59 S.B. 1/2 5.24 10.34 3.08 •3/4 2.78 4.54 1.10 B.I. 1/2 4.40 6.32 2.64 3/4 5.41 16.50 1.66 D.I. 1/2 4.09 6.42 3.12 3/4 4.34 8.17 1.22 Spine W.I. 1/2 2.9 4.2 3.1 Length . -.• 3/4 4.1 5.6 2.1 (mm.) S.B. 1/2 4.6 6.2 1.9 3/4 4.9 6.8 3.8 B.I. 1/2 5.0 8.8 2.8 3/4 5.2 7.7 3.0 D.I. 1/2 4.6 6.0 3.0 3/4 5.3 6.8 3.2 Standard Sample Variance Sheffe's Test E r r o r Size Ratio Table of P r o b a b i l i t i e s 24.63 7 2.42 W.I. S.B. 3.1. 21.94 8 S.B. 0.3919 17.47 10 B.L. 0.0874 0.8309 14.52 12 D.I 0.2849 0.9972 0.9096 9.65 12 11.37 11 9.95 11 17.93 8 0.23 7 6.28 W.I. S.B. B.I. 0.51 8 S.B. 0.0018 0.64 10 B.I. 0.0393 0.5454 0.29 11 D.I.i 0.1046 0.2807 0.9616 0.31 11 1.43 11 0.31 11 0.79 8 0.42 5 3.19 W.I. S.B. B.I. 0.51 7 S.B. 0.1583 0.40 10 B.I. 0.0387 0.8876 0.24 11 D.I. O.I3O7 0.9998 0.9120 0.51 11 0.48 11 0.26 11 0.45 7 Feature Location Posn. Mean Max. Min. on Frond Pneumato- W.I. 1/2 55.8 70.0 40.0 cyst 3/4 51.5 70.0 22.0 Length S.B. 1/2 50.9 65.0 35.0 (mm*) 3/4 63.5 85.0 45.0 B.I. 1/2 52.8 75.0 25.0 3/4 61.3 85.0 35.0 D.I. 1/2 37.5 50.0 20.0 3/4 39.3 50.0 30.0 Diameter W.I. 1/2 16.7 23.0 13.0 (mm.) 3/4 15.0 21.0 7.0 S.B. 1/2 16.0 20.0 11.0 3/4 16.7 20.0 11.5 B.I. 1/2 13.5 18.0 9.0 3/4 13.3"; 16.0 11.0 D.I. 1/2 11.5 15.0 6.0 3/4 12.1 13.0 11.0 Standard Sample Variance Sheff s Test Error Size Ratio Table of P r o b a b i l i t i e s 4.73 6 4.83 W.I. S.B. B.1. 5.03 8 S.B. 0.8755 3.27 10 B.I. 0.9648 0.9844 4.02 10 D.I. 0.0329 0.0897 0.0293 4.17 12 4.63 11 2.55 11 2.77 7 1.41 6 6.35 W.I. S.B. B.1• 1.58 8 S.B. 0.9762 0.81 10 B.I. 0.1967 0.2608 0.76 10 D.I. 0.0116 O.OIO5 0.4690 0.70 12 0.48 11 0.91 11 0.30 7 Location Stipe Lamina Length (m.) Diameter (mm.) Number #/L Width Terminal Splits Frond Mean Frond Mean Frond Mean Ratio Frond Mean Frond Mean 7) Port Hardy 3.75 3.75 6.0 6. 17 48 45.66 13.51 11.05 12.87 1 6.7 2.40 6.0 39 15.45 14 4.00 6.5 50 12. 10 5 1) Raglan 2.90 3.37 7.5 6.90 53 50.4 14.96 21.03 29.67 27 23.2 Point 3.16 7.5 51 24.10 20 3.40 6.5 49 16.53 25 3.60 6.0 46 18.66 16 3.80 7.0 53 23.05 28 3) Masterman 2.46 2.39 7.0 7.75 31 26.5 11.08 20.85 15.18 13 11.5 Island ; 2.32 8.5 22 9.50 10 . 8) Deer 7.00 7.22 8.5 7.83 49 51.99 7.06 15.70 16.26 5 5.7 Island 8.42 8.5 62 16.82 11 6.25 6.5 42 -- i 10) Cape 3.95 4.24 7.0 7.0 35 30.33 7.15 13.86 13.39 8 6.7 Daphne 6.00 7.0 29 14.60 5 2.78 7.0 27 11.70 7 9) Warren 6.00 4.67 9.5 9.10 43 39.12 8.39 13.58 9.88 9 5.2 Island 2.80 9.0 35 6.85 -6.40 10.0 46 9.03 12 7.30 11.0 53 10.05 5 0.87 6.0 19 -Table 4. Measurements of fronds collected throughout the spot sampling study. Arrangement is in order of increasing exposures. L o c a t i o n S t i p e Length (m) Diameter (mm. Frond Mean Frond Mean 2) A m p h i t r i t e P o i n t 4) Hope I s l a n d 5) Hope I s l a n d 6) Browning Passage 1.72 3.46 7.0 4.82 8.5 5.16 7.0 2.48 8.0 2.35 8.0 5.52 7.5 2.20 7.0 2.35 9.30 8.-0 6.95 9.5 5.90 6. 95 11.0 8.00 12.0 10.75 13.97 10.0 11.0 17.18 12.0 Table 4. Continued. Lamina Number Width Frond Mean Ra t i o Frond Terminal S p l i t s Mean Frond Mean 43 54 49 20 23 49 35 24 57 50 56 65 75 39.0 11.27 40.5 53.0 4.36 6.60 6.50 5.60 7.75 6.58 4.98 5.05 6.40 8.75 6.15 7.08 7.63 10.73 10.33 9.83 70.00 5.01 8.08 9.21 10.33 11 5 2 2 3 6 11 10 1.7 8.5 5.0 1.0 I CO I L o c a t i o n Lamina Spine Pneumatocyst Thickness (u) Cortex:Medulla Length (mm.) Length (mm.) Diameter mm.) Frond Mean Frond Mean Frond Mean Frond Mean Frond Mean 7) Port 254 292 9.00 8.57 4.2 4.3 50 62.5 9 12.0 Hardy 330 7.13 4.4 75 15 1) Raglan 367 347 6.01 6.14 6.2 5.7 65 62.4 25 23.8 P o i n t 366 4.29 6.6 60 23 295 6.43 4.0 55 23 359 7.72 6.0 70 24 3) Masterman 240 336 17.25 12.38 7.1 5.7 65 67.5 22 21.0 I s l a n d 432 7.50 4.4 70 20 8) Deer 352 352 10.93 10.93 6.2 6.2 110 110.0 18 . 18.0 I s l a n d 10) Cape ?339 331 4.42 5.94 - - - - - - 73.3 - 23.7 Daphne - - - - - - 85 27 80 25 323 7.46 55 19 9) Warren <505 598 4.98 4.78 - - 4.8 - - 97.5 - 25.5 I s l a n d - - - - - - 95 26 L691 4.57 4.8 100 25 Table 5. Measurements of blades obtained throughout the spot sampling study. Blades were taken from the 1/2 p o s i t i o n when a v a i l a b l e . Those marked w i t h an a s t e r i s k were taken from the 7/8 p o s i t i o n . Other symbols used are: (, from the same p l a n t ; i , immature lamina. L o c a t i o n Lamina Thickness (u) CortexrMedulla Frond Mean Frond Mean 2) A m p h i t r i t e VrO 491 5.46 5.39 f528 6.87 %18 5.38 *479 3.85 4) Hope 656 589 10.74 10.50 I s l a n d 521 9.46 5) Hope 571 580 10.70 10.65 I s l a n d 589 10.60 6) Browning 579 711 6.12 8.51 Passage 843 10.90 Table 5. Continued. Spine Pneumatocyst Length (mm.) Length (mm.) Diameter (mm.) Frond Mean Frond Mean Frond Mean 5.0 4.3 50 52.0 14 14.9 4.5 55 17.5 2.7 55 13 4.9 50 15 50 14 4.9 4.9 80 80.0 - 21.0 80 21 6.5 6.5 5.4 7.0 6.5 6.5 90 70 80 90 80.0 85.0 23 16 23 18 19.5 20.5 L o c a t i o n P l a n t Mean D a i l y Increment Maximum D a i l y Maximum Rate o f Lamina Number Through Exponential Phase Increment (cm./day) I n i t i a t i o n per Day Wizard 1 7.80 9.83 0.59 I s l e t 3 5.52 13.34 0.52 5 8.00 14.24 , 0.79 Sc o t t * s 1 2.80 3.82 0.32 Bay 3 3.23 3.48 - -5 2.70 3.42 0.32 . .7 - - 3.50 0.21 Bamfield 1 3.23 4.21 0.41 I n l e t 3 3.76 4.70 0.41 5 - - 3.00 0.25 Dixon 2 - - 3.53 0.42 Is l a n d 3 1.16 1.43v 0.36 4 . 4.53 0.42 5 • 3.30 4.25 0.27 Table 6. Growth of primary fronds and i n i t i a t i o n r a t e s f o r laminae recorded throughout the transplant study. l o c a t i o n P l a n t Lamina Max. Rate o f Number Number E l o n g a t i o n (cm./day) Wizard 1 5 4.17 I s l e t 16 3.50 2 3 2.84 7 2.96 3 2 2.83 4 3.94 10 3.14 S c o t t ' s 1 5 0.44 Bay 10 2.0.0 12 1.71 2 7 2.95 11 2.78 4 12 3.20 5 5 0.92 9 1.28 13 1.86 7 1 1.20 3 3.29 B a m f i e l d 3 1 1.66 I n l e t 2 *2.54 Dixon 2 2 3.69 I s l a n d 3 5.07 V a r i a n c e S c h e f f e ' s T e s t : R a t i o ( P ) Table o f P r o b a b i l i t i e s 3.78 W.I. S.B. B . I . S.B. 0.1710 B . I . 0.7153 0.9984 D.I. 0.7333 0.0522 0.2568 Table 7. Growth o f laminae on p l a n t s i n v o l v e d i n the t r a n s p l a n t s t u d y . The term " v a r i a n c e r a t i o " i s e x p l a i n e d i n the RESULTS. P r o b a b i l i t y v a l u e s are f o r common means. T a b l e 8. T r a n s p l a n t s t u d y . V a r i a t i o n w i t h time o f the mean number o f b l a d e s per meter o f s t i p e f o r p r i m a r y f r o n d s . L o c a t i o n V i z a r d I s l e t S c o t t ' s Bay B a m f i e l d I n l e t D ixon I s l a n d P l a n t # 1 3 5 1 5 7 1 3 5 3 4 5 1/07/70 26.32 17.74 38.46 30/07/70 31/07/70 17.27 43.47 27.65 13.72 10.94 20.00 13/08/70 15/08/70 16/08/70 17/08/70 12.27 18.46 12.85 9.82 10.97 11.76 20.00 33.33 33.33 35.00 38.46 27/08/70 29/08/70 11.33 12.93 9.58 22.50 29.09 43.75 30/08/70 9.45 7.69 9.78 15.39 23.33 - - --2/10/70 3/10/70 9.82 7.81 9.73 8.60 9.90 6.55 16.67 16.15 25.00 15.66. 6.42 15.18 31/10/70 8.38 6.61 8.50 8.57 9.87 - - - 9.73 10.65 13.71 12.50 - - - 10.39 5/12/70 8.81 6.36 8.24 L o c a t i o n - Wizard I s l e t S c o t t ' s Bay B a m f i e l d I n l e t Dixon I s l a n d P l a n t # - 1 3 5 1 2 3 5 7 1 3 5 1 2 3 4 5 1 11.5 7.0 8.2 - - - - - - 11.8 14.1 17.0 13.5 8.0 11.3 7.2 7.0 2 9.3 - - 9.0 14.0 15.1 17.2 11.0 16.0 10.7 12.5 11.8 3 11.0 9.0 9.6 7.4 16.5 15.0 21.0 15.0 11.0 19.6 - - 17.0 - -4 10.8 10.5 7.1 12.0 8.8 7.5 7.2 _ ~ 12.8 13.8 20.2 - - 21.0 10.8 03 5 13.3 12.2 11.1 9.8 12.5 13.3 - - 21.4 13.9 12.5 - - 13.0 17.1 ft •H 6 10.7 10.5 13.0 13.1 11.0 11.5 - - 21.9 16.6 10.6 - - - - - - 10.7 - -7 15.4 13.0 15.2 13.5 11.9 7.6 22.2 10.3 13.0 - - 20.0 - - - - 17.0 8 17.0 14.0 15.2 13.4 . - - 19.1 9 15.7 16.0 18.5 15.4 14.6 10 17.7 — — 17.0 14.8 16.8 8.6 9.7 - - - — - — - — - - _ — - - — -T a b l e 9. T r a n s p l a n t s t u d y . . . maximum w i d t h , i n c e n t i m e t e r s , o f mature laminae numbered from the base o f the p r i m a r y s t i p e . -70-LITERATURE CITED B r a n d t , R.P. 1923. P o t a s h from K e l p : e a r l y development and growth o f t h e g i a n t k e l p , M a c r o c y s t i s p y r i f e r a . P u b l . U.S. Dept. o f A g r i c . No. 1191, Wash. D.C., 40 pp. Burrows, E.M. 1958. S u b l i t t o r a l a l g a l p o p u l a t i o n i n P o r t E r i n Bay, i s l e o f Mann. J . Mar. B i o l . A s s . U.K. 37:687-703. C l e n d e n n i n g , K.A. 1971. P h o t o s y n t h e s i s and g e n e r a l d e v e l o p -ment i n M a c r o c y s t i s i n The B i o l o g y o f G i a n t K e l p Beds ( M a c r o c y s t i s ) i n C a l i f o r n i a . (Ed.) Wheeler J . M o r t h B e i h e f t e z u r Nova Hedwegia 32:169-190. C r i b b , A.B. 1954. M a c r o c y s t i s p y r i f e r a (L.) Ag. i n Tasman-i a n W a t e r s . A u s t r a l . J o u r . M a r i n e Freshw. Res. 5:1-34. D r u e h l , L.D. 1967. D i s t r i b u t i o n o f two s p e c i e s o f L a m i n a r i a as r e l a t e d t o some e n v i r o n m e n t a l f a c t o r s . J o u r n a l o f P h y c o l o g y 3(2):103-108. Hooker, J.D. 1847. The botany o f t h e A n t a r c t i c voyage o f H.M. d i s c o v e r y s h i p s Erebus and T e r r o r , v o l . 1 . F l o r a A n t a r c t i c a , P t . 2, A l g a e , Reeve B r o s . , Lond. pp 209-574. K a i n , J.M. 1962. A s p e c t s o f t h e b i o l o g y o f L a m i n a r i a h y p e r -b o r e a I . v e r t i c a l d i s t r i b u t i o n . J . Mar. B i o l . A s s . U.K. 42:377-385. K a i n , J.M. 1971. The b i o l o g y o f L a m i n a r i a h y p e r b o r e a . V I . Some Norwegian P o p u l a t i o n s . J . Mar. B i o l . A s s . U.K. 51:387-408. L i n d a u e r , V.W., Chapman, V . J . , a n d ' A i k e n , M. 1961. The M a r i n e A l g a e o f New Z e a l a n d . P t . IV. Phaeophyceae. Nova Hed-w e g i a , v o l . 3(2) :129-350. - 7 1 -M a c F a r l a n e , C M . 1959. Some e c o l o g i c a l p r o b l e m s e n c o u n t e r e d i n s u r v e y s o f m a r i n e a l g a e i n Nova S c o t i a . Rec. Adv. i n B o t a n y . 9:183-187. Moore, L.B. 1943. O b s e r v a t i o n s on t h e g r o w t h o f M a c r o c y s t i s i n New Z e a l a n d . T r a n s . Roy. Soc. N.2. 72(4):333-343. N e u s h u l , M. 1971. The s p e c i e s o f M a c r o c y s t i s w i t h p a r t i c u l a r r e f e r e n c e t o t h o s e o f N o r t h and S o u t h A m e r i c a , i n The B i o l o g y o f G i a n t K e l p Beds ( M a c r o c y s t i s ) i n C a l i f o r n i a . (Ed.) Wheeler J . N o r t h . B e i h e f t z u r Nova Hedwegia. 32: 211-222. N e u s h u l , M. & Haxo, F.T. 1963. S t u d i e s on t h e g i a n t k e l p , M a c r o c y s t i s . I . growth o f young p l a n t s . Amer. J o u r . B o t . 50:349-355. N o r t h , W.J. 1971. The B i o l o g y o f G i a n t K e l p Beds ( M a c r o c y s t i s ) i n C a l i f o r n i a . I n t r o d u c t i o n and Background. B e i h e f t z u r Nova Hedwegia. 32:1-97. N o r t o n , T.A. 1969. Growth form and environment i n s a c c o r h i z a  p o l y s c h i d e s . J . Mar. B i o l . A s s . U.K. 49:1025-1045. P a r k e , M.W. 1948. S t u d i e s on t h e B r i t i s h L a m i n a r i a c e a e I Growth i n L a m i n a r i a s a c c h a r i n a (L.) Lamour. J . Mar. B i o l . A s s . U.K. 27:651-709. P a r k e r , Bruce C. 1965. T r a n s l o c a t i o n i n t h e g i a n t k e l p Macro-c y s t i s . I . R a t e s , d i r e c t i o n , q u a n t i t y o f C ^ l a b e l l e d p r o -d u c t s and f l u o r e s c e i n . J o u r n a l o f P h y c o l o g y l ( 2 ) : 4 1 - 4 6 . S a r g e n t , M.C. and L a n t r i p , L.W. 1952. P h o t o s y n t h e s i s , growth and t r a n s l o c a t i o n i n t h e g i a n t k e l p . Amer J o u r . B o t . 3 9 ( 2 ) : 99-107. S c a g e l , R.F. 1948. An i n v e s t i g a t i o n on M a r i n e P l a n t s near Hardy Bay, B.C. P r o v . Dept. F i s h . V i c t o r i a , B.C. Pub. No. 1, 70 pp. -72-S k o t t s b e r g , C. 1907. Zur k e n n t n i s d e r S u b a n t a r k t i s c h e n and A n t a r c t i s c h e n m e e r e s a l g e n . 1. Phaeophyceen. 171 pp. U p s a l l a . S m i t h , G.M. 1944. M a r i n e a l g a e o f t h e Monterey P e n i n s u l a , C a l i f . S t a n d o r d U n i v . P r e s s , S t a n f o r d , C a l i f . , 622 pp. S o u t h , G.R. 1970. E x p e r i m e n t a l c u l t u r e o f A l a r i a i n a sub-a r c t i c , f r e e f l o w i n g sea w a t e r s y s t e m . H e l g o l a n d e r w i s s . M e e r e s u n t e r s . 20:216-228. Sundene, Ove 1958. I n t e r f e r t i l i t y between forms o f L a m i n a r i a  d i q i t a t a . N y t t . Mag. B o t . 6:121-128. Sundene, Ove 1961a. Growth i n t h e sea o f L a m i n a r i a d i g i t a t a s p o r o p h y t e s from c u l t u r e . N y t t . Mag. B o t . 9:5-24. Sundene, Ove 1961b. The i m p l i c a t i o n s o f t r a n s p l a n t and c u l -t u r e e x p e r i m e n t s on t h e growth and d i s t r i b u t i o n o f A l a r i a  e s c u l e n t a . N y t t . Mag. B o t . 9:155-174. Sundene, Ove 1964. The e c o l o g y o f L a m i n a r i a d i g i t a t a i n Norway i n v i e w o f t r a n s p l a n t e x p e r i m e n t s . N y t t Mag. B o t . 11:83-108. Widdowson, T.B. 1964. A Taxonomic Study o f t h e Genus H e d o p h y l -lum ( S e t c h e l l ) . Can. J o u r . B o t . 43:1409-1420. Womersley, H.B.S. 1954. The s p e c i e s o f M a c r o c y s t i s w i t h s p e c i a l r e f e r e n c e t o t h o s e on s o u t h e r n A u s t r a l i a n c o a s t s . f i TABLE OF CONTENTS PART I I Page ABSTRACT LIST OF TABLES LIST OF FIGURES INTRODUCTION . . 1 MATERIALS AND METHODS . . . 2 A p p a r a t u s 2 P r e p a r a t i o n and A n a l y s i s o f C u l t u r e S l i d e s 2 C o n t r o l o f GeQo l e v e l 3 E f f e c t on t h e Gametophyte and E a r l y S p o r o p h y t e 4 RESULTS AND DISCUSSION .... . 6 FIGURES , 8 TABLES 12 LITERATURE CITED 14 ABSTRACT A f i e l d c u l t u r e a p p a r a t u s e m p l o y i n g germanium d i o x i d e t o i n h i b i t d i a t o m growth was d e s i g n e d and t e s t e d . Through two e x p e r i m e n t s , s e t up a t B a m f i e l d on t h e west c o a s t o f Vancouver i s l a n d , a d e s i g n was a c h i e v e d w h i c h p r o v i d e d s a t i f a c t o r y c o n t r o l f o r up t o 33 days on l e s s t h a n 1 gm o f t h e i n h i b i t o r . A d v e r s e e f f e c t s on t h e m i c r o s c o p i c phases o f M a c r o c y s t i s i n t e q r i f o l i a Bory a t t r i b u t a b l e t o t h e p r e s e n c e o f Ge02 were not d e t e c t e d . L I S T OF FIGURES FIGURE Page 1 S c h e m a t i c r e p r e s e n t a t i o n o f t h e in_ s i t u 8 c u l t u r e a p p a r a t u s . 2 The assembled c u l t u r e a p p a r a t u s . 9 3 Experiment 1. Mean number o f d i a t o m s p e r 10 sample on s l i d e s c o l l e c t e d f r om t h e f i e l d a t 4 day i n t e r v a l s t h r o u g h o u t t h e p e r i o d August 6 t o 30, 197 0. 4a,b Comparison o f s l i d e s t r e a t e d and u n t r e a t e d 11 w i t h germanium d i o x i d e o v e r a p e r i o d o f 33 days i n t h e s e a . L I S T OF TABLES TABLE Page 1 V a r i a t i o n s i n t h e s i z e and p o s i t i o n o f t h e 12 se c o n d a r y i n f l o w p o r t . 2 Mean number o f diat o m s p e r sample on s l i d e s 12 c o l l e c t e d a f t e r 33 days c o v e r i n g t h e p e r i o d O c t . 12 t o Nov. 14, 1970. 3 Development o f gametophytes and young s p o r o - 13 p h y t e s a t -7.5 m e t e r s . - 1 -INTRODUCTION A common p r o b l e m i n c u l t u r e s t u d i e s o f m i c r o s c o p i c phases o f marine a l g a e has been the a c c u m u l a t i o n and growth o f c o n t a m i n a n t s , t h e most n o t a b l e o f t h e s e b e i n g d i a t o m s . H i g h c o n c e n t r a t i o n s o f diato m s impede m i c r o s c o p i c e x a m i n a t i o n o f c u l t u r e s l i d e s and may a l s o i n h i b i t normal g r o w t h and development o f gametophytes i n t h e L a m i n a r i a l e s ( N o r t h , 1970). T h i s p r o s p e c t i s o f p a r t i c u l a r s i g -n i f i c a n c e as t h e p r e s e n t s t u d y was b o r n o ut o f an a t t e m p t t o c u l -t u r e the gametophyte and e a r l y s p o r o p h y t e o f M a c r o s y s t i c i n t e g r i -f o l i a B o r y under n a t u r a l c o n d i t i o n s . A major advancement i n t h e c o n t r o l o f d i a t o m c o n c e n t r a t i o n s i n l a b o r a t o r y c u l t u r e s t u d i e s has been t h e use o f germanium d i -o x i d e (GeC>2) i n c o n c e n t r a t i o n s o f 1 t o 10 mg/1 (Lewin, 1966) . I n v i e w o f t h e h i g h l e v e l o f c o n t r o l a t t a i n e d i t appeared f e a s -i b l e t o e x t e n d t h i s t e c h n i q u e t o f i e l d c u l t u r e s t u d i e s . Lewin has d e m o n s t r a t e d t h a t c o n c e n t r a t i o n s o f GeC>2 as h i g h as 64 mg/1 d i d n o t a f f e c t t h e g r o w t h r a t e o f Chlamydomonas m o e w u s i i , a non-s i l i c i f i e d g r e e n f l a g e l l a t e . S i m i l a r e v i d e n c e has n o t been ob-t a i n e d f o r t h e gametophyte o r young s p o r o p h y t e i n t h e L a m i n a r i a l e s . The use o f GeC>2 i n undetermined s t r e n g t h i n the f i e l d however, a t t a c h e d new s i g n i f i c a n c e t o t h i s q u e s t i o n . An e x p e r i m e n t was con d u c t e d t o d e t e c t and a s s e s s t h e e x t e n t o f t h i s p r o b l e m . < -2-MATERIALS AND METHODS A p p a r a t u s An i n s i t u c u l t u r e a p p a r a t u s ( F i g . 1) was d e s i g n e d w h i c h u t i l i z e d n a t u r a l t i d a l c u r r e n t f l o w s i n i t s o p e r a t i o n . The r e -s e a r c h s i t e chosed was l o c a t e d a t t h e mouth o f B a m f i e l d I n l e t on ' t h e west c o a s t o f Vancouver I s l a n d . A s e m i - d i u r n a l t i d a l c y c l e p r o v i d e d a r e g u l a r ebb and f l o w c u r r e n t w i t h a maximum o f about one k n o t . The c u l t u r e chamber c o n s i s t s o f a p e r s p e x c y l i n d e r w h i c h accommodates s i x g l a s s s l i d e s (37 x 25 mm) i n s e r i e s . These a r e h e l d i n p l a c e b y a b o r d e r o f p l a s t i c t u b i n g on e a c h s i d e . To t h e f o r w a r d ( i n f l o w ) and o f t h e chamber i s a t t a c h e d a Ge0 2 d i f f u s e r c o n s i s t i n g o f a f u n n e l w h i c h a m p l i f i e s and d i r e c t s t h e c u r r e n t t h r o u g h a Nalgene a s p i r a t o r t y p e vacuum pump. To t h e s u c t i o n n o z z l e o f t h e vacuum pump i s a t t a c h e d a 60 m l . p l a s t i c b o t t l e c o n -t a i n i n g 1 g o f Ge02. Removal o f a p e r f o r a t e d r u b b e r s t o p p e r p l a c e d a t t h e o u t f l o w end o f t h e chamber p e r m i t s a c c e s s t o t h e c u l t u r e s l i d e s . Two a p p a r a t i a r e p o s i t i o n e d s i d e b y s i d e on a p l a s t i c s t a n d ( F i g . 2 ) . The f o r w a r d end o f t h e s t a n d i s a t t a c h e d d i r e c t l y , by s w i v e l c o n n e c t o r s , t o a main p o s i t i o n i n g l i n e r u n n i n g v e r t i c a l l y between an a nchor and a f l o a t . Two m o n o f i l a m e n t s u p p o r t l i n e s s e r v e t o l e v e l the s t a n d w h i l e a f i n a t t h e a f t end keeps t h e d i f -f u s e r s f a c i n g i n t o t h e c u r r e n t . The a p p a r a t u s i s assembled and m a i n t a i n e d t h r o u g h t h e use o f SCUBA. P r e p a r a t i o n and A n a l y s i s o f C u l t u r e S l i d e s The c u l t u r e s l i d e s were p l a c e d i n t h e b o t t o m o f a p l a s t i c a q u arium (21 x 31 cm) c o n t a i n i n g 1200 ml o f f i l t e r e d s e a w a t e r . C o o l i n g w a t e r was pumped c o n t i n u o u s l y from B a m f i e l d I n l e t . The s l i d e s were i n n o c u l a t e d from a f r e s h spore s u s p e n s i o n and m a i n -• - 3 -t a i n e d f o r 24 h o u r s i n t h e d a r k . The young gametophytes were l a b e l l e d f o r f u t u r e i d e n t i f i c a t i o n w i t h C a l c o f l u o r White f l u o u r -e s c e n t b r i g h t e n e r a t 0.01% f o r two h o u r s ( from C o l e , 1 9 6 4 ) . T h i s s u b s t a n c e was t a k e n up b y t h e c e l l w a l l s and c o u l d s t i l l be d e t e c t e d under U.V. l i g h t a f t e r 33 days i n t h e s e a . The p r e p a r e d s l i d e s were p l a c e d i n t h e p l a s t i c g u i d e s and i n s e r t e d i n t o the c u l t u r e chambers. These were t r a n s p o r t e d i n s e a w a t e r t o t h e s i t e and p l a c e d i n p o s i t i o n on t h e c u l t u r e s t a n d s . S l i d e s p e r i o d i c a l l y c o l l e c t e d from t h e chambers were p l a c e d i n 5% f o r m a l i n / s e a w a t e r s o l u t i o n f o r f u t u r e s t u d y . E f f i c i e n c y o f c o n t r o l was a s s e s s e d b y c o u n t i n g t h e t o t a l number o f d i a t o m s c r o s s e d b y a 0.03 9 mm h o r i z o n t a l l i n e a t 400X o v e r a v e r t i c a l d i s -t a n c e o f 15 mm. V a l u e s g i v e n i n t h e t e x t r e p r e s e n t t h e mean o f t h r e e random sam p l e s . C o n t r o l o f GeCb L e v e l The s o l u t i o n r a t e o f t h e Ge0 2 was a d j u s t e d b y a l t e r i n g t h e s i z e and p o s i t i o n o f an i n f l o w p o r t i n t h e s i d e o f the i n h i b i t o r b o t t l e . The d i a m e t e r of t h i s p o r t d e t e r m i n e s th e amount o f w a t e r e n t e r i n g t h e chamber by way o f t h i s s e c o n d a r y r o u t e . The h e i g h t o f t h e p o r t above t h e base o f the b o t t l e d e t e r m i n e s the e x t e n t t o w h i c h eddy d i f f u s i o n i n f l u e n c e s t h e s o l u t i o n r a t e . Two e x p e r i m e n t s were c o n d u c t e d w i t h t h e aim o f a c h i e v i n g a d e s i g n t h a t would p r o -v i d e a d e s i r a b l e l e v e l o f d i a t o m c o n t r o l w i t h a m i n i m a l uptake o f t h e i n h i b i t o r . E x p e r i m e n t 1 was s e t up a t a d e p t h o f 5 meters b e low z e r o t i d e l e v e l on A ugust 5, 1970. Three v a r i a t i o n s i n t h e s i z e and p o s i t i o n o f the s e c o n d a r y i n t a k e p o r t were t e s t e d (Table 1, t e s t d e s i g n s A,B,C). The r a t e o f uptake o f the i n h i b i t o r i n c r e a s e s t h r o u g h d e s i g n s A t o C. Two c r y s t a l l i n e forms o f t h e i n h i b i t o r d i f f e r i n g w i d e l y i n s o l u b i l i t y were employed. A r e l a t i v e l y s l o w -d i s s o l v i n g form s u p p l i e d by t h e F i s h e r S c i e n t i f i c Co. was used i n -4-t e s t d e s i g n s A, B and C, w h i l e a more s o l u b l e form s u p p l i e d b y t h e B r i t i s h Drug House was used o n l y i n d e s i g n s A and B ( d e s i g n a t e d D and E) . A l l t e s t s were r u n a g a i n s t a c o n t r o l l a c k i n g GeC>2 • S l i d e s were c o l l e c t e d a t i n t e r v a l s o f 4 d a y s . Through t h e d u r a t i o n o f e x p e r i m e n t 1 a w e l l d e f i n e d p l a n k -t o n bloom o c c u r r e d i n B a m f i e l d I n l e t and a d j a c e n t w a t e r s . From v i s u a l o b s e r v a t i o n s made d u r i n g t h e p r e v i o u s y e a r and s u p p o r t e d b y Secche d i s c r e a d i n g s * , i t was e x p e c t e d t h a t t h i s bloom would cease d u r i n g l a t e August o r e a r l y September t o be f o l l o w e d b y a bloom l a s t i n g o n l y about two weeks i n e a r l y O c t o b e r . A second e x p e r i m e n t s e t up i n e a r l y F a l l would t h e r e f o r e s e r v e t o demon-s t r a t e t h e r e l a t i o n s h i p between t h e r e l a t i v e e f f i c i e n c y o f each d e s i g n and s e a s o n a l f l u c t u a t i o n s i n t h e c o n c e n t r a t i o n o f di a t o m s i n t h e w a t e r column. E x p e r i m e n t 2 was s e t up on October 12 a t t h e same d e p t h and l o c a t i o n as e x p e r i m e n t 1. T e s t d e s i g n s A, B and C e m p l o y i n g o n l y t h e l e s s s o l u b l e f o rm o f the i n h i b i t o r were r u n a g a i n s t a c o n t r o l . One c o l l e c t i o n o f s l i d e s was made a f t e r 33 d a y s . E f f e c t on t h e Gametophyte and E a r l y S porophyte The development o f t h e gametophyte and e a r l y s p o r o p h y t e was compared u s i n g p l a n t s t r e a t e d w i t h Ge0 2 and c o n t r o l s . C o n t r o l s l i d e s from t h e p r e v i o u s e x p e r i m e n t s c o u l d n o t be used f o r t h i s p urpose due t o t h e h i g h c o n c e n t r a t i o n s o f diat o m s p r e s e n t . A s i n g l e s t a n d was s e t up on August 6, 1970 a t a d e p t h o f -7.5 m e t e r s . A t t h i s l e v e l a d i s t i n c t i n c r e a s e i n v i s i b i l i t y was f e l t t o i n d i c a t e a d e c r e a s e i n d i a t o m c o n c e n t r a t i o n s . A t e s t a p p a r a t u s o f d e s i g n C e m p l o y i n g t h e F i s h e r form o f Ge02 was r u n a g a i n s t a c o n t r o l . S l i d e s were c o l l e c t e d a t i n t e r v a l s o f 4 d a y s . A system d e s c r i b e d by N o r t o n and Burrows (1968) was used t o a s s e s s t h e r a t e o f development o f t h e p l a n t s . The p r e s e n c e o r ab-sence o f t h e f o l l o w i n g s t a g e s were r e c o r d e d : *Data of the Bamfield Station. . _ 5 - • 1) t h e ungerminated s p o r e ; 2) a s p o r e w i t h a germ t u b e , c h a r a c t e r i s t i c a l l y d u m b e l l shaped; 3 ) a gametophyte w i t h e i t h e r a n t h e r i d i a o r an e x t r u d e d egg; 4) s p o r o p h y t e p r o d u c e d b u t composed o f o n l y 10 c e l l s o r l e s s 5) s p o r o p h y t e composed o f 11 t o 20 c e l l s ; 6) s p o r o p h y t e composed o f 21 t o 30 c e l l s ; 7) s p o r o p h y t e composed o f 31 t o 50 c e l l s ; 8) s p o r o p h y t e composed o f 51 t o 100 c e l l s . R e c o r d i n g s were made o f 40 p l a n t s on each c u l t u r e s l i d e , and t h e r e s u l t s o f t h i s e x p e r i m e n t a r e p r e s e n t e d i n T a b l e 3. - 6 -RESULTS AND DISCUSSION Diatom c o n c e n t r a t i o n s were s a t i s f a c t o r i l y r e d u c e d i n t e s t d e s i g n s B, C, D, E and A, B, C o f e x p e r i m e n t s 1 and 2 r e s p e c t i v e l y ( F i g . 3, T a b l e 2 ) . That t h i s e f f e c t can be a t t r i b u t e d t o t h e use o f t h e i n h i b i t o r i s d e m o n s t r a t e d b y t h e c o n t r o l s i n b o t h e x p e r -i m e n t s . I n d e s i g n A t h e i n f l o w p o r t was r e s t r i c t e d i n d i a m e t e r and p l a c e d w e l l above the b o t t o m o f t h e i n h i b i t o r b o t t l e . The r e d u c e d c i r c u l a t i o n r e s u l t e d i n a l o w s o l u t i o n r a t e o f t h e i n h i b i t o r and a h i g h l e v e l o f d i a t o m c o n t a m i n a t i o n . The use o f a more s o l u b l e form o f t h e i n h i b i t o r i n a b o t t l e o f t h e same d e s i g n (D) i n e x -p e r i m e n t 1 r e s u l t e d i n a d e f i n i t e s u p p r e s s i o n o f d i a t o m g r o w t h . The u n i f o r m i t y o f r e s u l t s o b t a i n e d from t e s t s B, C, D and E s u g g e s t s a l i m i t i n t h e e f f i c i e n c y o f the a p p a r a t u s beyond w h i c h f u r t h e r p e r c e n t r e d u c t i o n s i n d i a t o m c o n c e n t r a t i o n s c o u l d n o t be a c h i e v e d . The p l a n k t o n bloom found t o o c c u r t h r o u g h o u t e x p e r i m e n t 1 r e s u l t e d i n the a c c u m u l a t i o n o f r e l a t i v e l y l a r g e numbers o f d i a -toms on a l l s l i d e s . A l t h o u g h a s h o r t bloom d i d o c c u r d u r i n g t h e e a r l y s t a g e s o f e x p e r i m e n t 2 the w a t e r had c o m p l e t l y c l e a r e d b y t h e 3 3 r d day. The r e s u l t s i n d i c a t e t h a t under s u c h c o n d i t i o n s a l -most complete e l i m i n a t i o n o f d i a t o m s c o u l d be a c h i e v e d ( F i g . 4 a , b ) . A v i s u a l i n s p e c t i o n o f a l l Ge0 2 b o t t l e s i n e x p e r i m e n t 1 a f t e r 26 days i n d i c a t e d t h a t o n l y i n t e s t d e s i g n C was r e p l e n i s h m e n t r e -q u i r e d . The i n h i b i t o r was c o m p l e t e l y d e p l e t e d from t h e same b o t t l e i n e x p e r i m e n t 2 a f t e r 33 d a y s . I n l i g h t o f t h i s f a c t t h e d i s c r e p -e n c i e s o b s e r v e d between t e s t s B end C o f e x p e r i m e n t 2 a r e not c o n -s i d e r e d s i g n i f i c a n t . An o v e r a l l e v a l u a t i o n s u g g e s t s t h a t a l a r g e i n f l o w p o r t p l a c e d n e a r t h e t o p o f t h e i n h i b i t o r b o t t l e ( d e s i g n B) p r o v i d e s op-t i m a l c o n t r o l . F u r t h e r i n c r e a s e s i n t h e c o n c e n t r a t i o n o f Ge02 were a c h i e v e d b y l o w e r i n g t h e l e v e l o f t h e i n f l o w p o r t as i n d e s i g n C o r b y u s i n g a more s o l u b l e form o f t h e i n h i b i t o r a r e not r e q u i r e d . Whereas p l a n t s grown on c o n t r o l s l i d e s tended n ot t o p r o -duce s p o r o p h y t e s , t h o s e s u b j e c t e d t o GeC-2 f o l l o w e d a development-a l sequence c h a r a c t e r i s t i c o f t h e o r d e r . This d i s c r e p a n c y may be r e l a t e d t o a d v e r s e e f f e c t s c a u s e d by the g r e a t e r a c c u m u l a t i o n o f diatoms on t h e c o n t r o l s l i d e s ( N o r t h 1 9 7 0 ) . There i s i n s u f f i c i e n t e v i d e n c e t o s u p p o r t t h e a l t e r n a t i v e p o s s i b i l i t y t h a t t h e i n h i b -i t o r had a s t i m u l a t i n g e f f e c t on t h e p l a n t s under s t u d y . As t h e a p p a r a t u s was t e s t e d under a l i m i t e d s e t o f c o n d i t i o n s , i t i s c o n s i d e r e d l i k e l y t h a t f a c t o r s even more c o n d u c i v e t o d i a -tom c o n t a m i n a t i o n c o u l d be e n c o u n t e r e d . F o r example, any i n -c r e a s e i n the c o n c e n t r a t i o n o f diat o m s i n t h e w a t e r column would t e n d t o cause a p r o p o r t i o n a t e b u i l d - u p o f d i a t o m s on t h e c u l t u r e s l i d e s . The f l o w o f seaw a t e r t h r o u g h t h e c u l t u r e chamber c o u l d be, s u b s e q u e n t l y r e d u c e d t h r o u g h such m i n o r m o d i f i c a t i o n s i n d e s i g n as t h e use o f a s m a l l i n t a k e f u n n e l . Uptake o f t h e i n h i b i t o r c o u l d be a d j u s t e d a c c o r d i n g l y . C o n t a m i n a t i o n b y organisms o t h e r t h a n d i a t o m s was n o t a s i g -n i f i c a n t p r o b l e m i n t h e e x p e r i m e n t s a l t h o u g h a g r a d u a l t h i n n i n g o u t o f gametophytes s t r o n g l y s u g g e s t s t h e p r e s e n c e o f h e r b i v o r e s . A l a r g e v a r i e t y o f z o o p l a n k t e r s were' o b s e r v e d from t i m e t o t i m e b u t t h e s e tended t o r e m a i n s p a r s e l y s c a t t e r e d o v e r t h e s l i d e s . Season-a l v a r i a t i o n s i n t h e n a t u r e and e x t e n t o f t h i s p r o b l e m have been d i s c u s s e d b y Jones and Dent (1970). The b a s i c p r i n c i p l e b e h i n d t h e d e s i g n and o p e r a t i o n o f t h e a p p a r a t u s p e r m i t s some degree o f v e r s a t i l i t y . I n some l o c a l i t i e s i t may be more c o n v e n i e n t t o adapt the a p p a r a t u s t o c u r r e n t f l o w s o t h e r t h a n t h o s e g e n e r a t e d by t i d e s . These i n c l u d e r i v e r s and v e r t i c a l and h o r i z o n t a l components o f wave m o t i o n . F i g . 1. Schematic r e p r e s e n t a t i o n o f the i n s i t u c u l t u r e a p p a r a t u s . C u r r e n t f l o w i s from r i g h t t o l e f t . b. b a r r i e r s c r e e n , c.c. c u l t u r e chamber, c s . c u l t u r e s l i d e s , f . f u n n e l , i . i n h i b i t o r b o t t l e , i . p . s e c o n d a r y i n f l o w p o r t , o.p. o u t f l o w p o r t , v. vacuum pump. F i g . 2. The assembled culture apparatus. - 9 -F i g . 3. Experiment 1. Mean number of diatoms per sample on s l i de s c o l l e c t e d from the f i e l d at 4 day i n t e r v a l s throughout the per iod August 6 to 30, 1970. Each l i ne represents a d i f -ferent tes t des ign of the cu l ture apparatus ( re fer to Table 1) . Ge02 was used in a l l designs except the con t ro l (F) . Data for design E, for the purpose of c l a r i t y , was not inc luded i n the graph, having conformed c l o s e l y wi th that of designs B, C, and D. Due to over lapping and clumping i t was not pos-s i b l e to take samples from s l i de s F and A a f t e r 8 and 12 days r e spec t i v e l y . Mean Number of Diatoms per Sample X IOO ro co . tn . o» -ox-t. Figure 4. Comparison of s l i d e s t r e a t e d (a) and untreated (b) w i t h GeC>2 over a p e r i o d of 33 days i n the sea. Note the young sporophyte which i s attached to the empty oogonium i n ( a ) . -11--12-Table 1 q V a r i a t i o n s i n the s i z e and p o s i t i o n of the secondary i n f l o w p o r t . Test Design L e v e l of Infl o w Port Diameter of I n f l o w Port A (D) 1 3/4" 1/32" B (E) 1 3/4" 3/16" C 1/2" 3/16" Table 2 Mean number of diatoms per sample on s l i d e s c o l l e c t e d a f t e r 33 days c o v e r i n g the p e r i o d Oct. 12 - Nov. 14, 1970. 'Test Design R e s u l t s A 111.3 B 3.6 C 73.3 C o n t r o l 748.5 - 1 3 -T a b l e 3 Development of gametophytes and young sporophytes  -7.5 meters. S l i d e Developmental Stage 5 6 7 8 Category* Days •1 2 3 4 C 5 1 39 T 5 - 40 C 9 - 40 T 9 - 40 C 13 - 23 17 T 13 - 9 31 C 17 - 1 39 T 17 No Info r m a t i o n C 21 No Info r m a t i o n T 21 - 1 14 7 C 25 - 1 38 1 T 25 — 14 3 * C - c o n t r o l s l i d e s T - t e s t s l i d e s s u bjected to Ge02 12 - 1 4 -LITERATURE CITED C o l e , K. 1964. Induced f l u o r e s c e n c e i n gametophytes o f some L a m i n a r i a l e s . Cndn. J . Botany , 42:1173-1181. Jon e s , W. E. and Dent, E. S. 1970. C u l t u r e o f marine a l g a e u s i n g a r e - c i r c u l a t i n g sea w a t e r s y s t e m . H e l g o l a n d e r w i s s . M e e r e s u n t e r s , 20:70-78. L e w i n , J . 1966. S i l i c o n M e t a b o l i s h i n D i a t o m s . V. Germanium D i o x i d e , a S p e c i f i c I n h i b i t i o r o f Diatom Growth. P h y c o l o g i a 6 ( 1 ) : 1 - 1 2 . N o r t h , W. J . 1970. C u l t u r e and "S e e d i n g " M a c r o c y s t i s . K e l p Hab. Imp. P r o j . , A n n u a l R e p o r t , 1965-66, C a l i f . I n s t . Tech.:36-51. N o r t o n , T. A. and Burrows, E. M. 1969. The e n v i r o n m e n t a l c o n t r o l o f t h e s e a s o n a l development o f S a c c o r h i z a p o l y s c h i d e s ( L i g h t . ) B a t t . P r o c . I n t l . Seaweed Symp., 6:287-2 96. 

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