UBC Theses and Dissertations
Can fatty acids, found in sediments from three coastal B.C. Inlets, be used as biomarkers to hindcast harmful algal blooms of Heterosigma akashiwo? Drost, Helen
This study presents fatty acid profiles of the harmful algae Heterosigma akashiwo. These profiles were generated to assess the variability in H. akashiwo fatty acid proportions and to compare the results with past research on this and other species of marine algae. Past research has identified several important fatty acids that are used as biomarkers for microbial functional groups including: diatoms, dinoflagellates, bacteria, zooplankton and terrestrial plants. Can the fatty acids found in sediments be used to trace the historical bloom events of H. akashiwo? This question was the focus of this study. Key fatty acids for this species were selected and used as probes to search for similar fatty acid proportions in marine sediments collected from three British Columbian Inlets near the Strait of Georgia. The sediments from Howe Sound, Hotham Sound and Malaspina Inlet showed considerable variation in fatty acid abundance. The latter Inlet had the highest concentration of acids whereas Howe Sound had the least. The fatty acid biomarkers for H. akashiwo were incorporated into a multivariate analysis of the sediment samples to locate the particular depths in the sediment that the proportions of these fatty acids matched the H. akashiwo profiles. The results were tested by comparing DNA counts for H. akashiwo that were extracted concurrently by another researcher using the same sediment samples from Hotham Sound and Malaspina Inlet. The DNA and fatty acid data were not in close agreement. Degradation limits the interpretive power of both DNA and fatty acid biomarkers found at depth in sediments. Further analysis using multi biomarkers including pigments and sterols could be incorporated into the method of analysis presented in this two part study.
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