Abundance of ammonia-oxidizing Archaea and Bacteria and their contribution to nitrous oxide emissions in woody perennial cropping systems
department or school: Arts and Sciences, Irving K. Barber School of (Okanagan)
department or school: Biology, Department of (Okanagan)
data provider: DSpace
degree campus: UBCO
creator: Hans, Geetkamal Kaur
issued: 2019-01-30T22:25:32Z
issued: 2019
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Nitrification is one of the processes responsible for the emissions of nitrous oxide (N₂O), an ozone-depleting greenhouse gas, from agricultural soil. In the first step of nitrification, catalyzed by the enzyme ammonia monooxygenase, ammonia is converted into hydroxylamine which further chemically decomposes into N₂O. The contribution of nitrifying Archaeal species to N₂O emissions in woody perennial cropping systems is not well understood. The first study reported here examined the effect of nitrogen application, mulch and soil depth on abundances of nitrifying Archaea and Bacteria, and total Archaea and Bacteria in an apple orchard and a grape vineyard. Soil samples were collected five times (2013-2015) and at three depths. Quantitative polymerase chain reaction was used to determine the abundances of total Archaeal (16SrRNAArch) and Bacterial (16SrRNABac) and nitrifying Archaeal (amoAArch) and Bacterial (amoABac) genes. Total Bacteria were more abundant than total Archaea and both decreased as depth increased. Nitrifying Archaeal abundance increased with depth. Abundance of nitrifying Bacteria was lower than that of nitrifying Archaea when compost was applied and there was no effect of mulch. The second study examined the effect of selective nitrification inhibitors, urea concentration, and soil depth on N₂O emissions in closed in vitro microcosms. Soil samples were collected from a grape vineyard in 2015 and 2016 at two depths (0-15, 15-30 cm). Increasing urea concentrations increased N₂O emissions. When urea was added, soils collected from 0-15 cm produced about 4 times more N₂O than soils collected from 15-30 cm soil depth. Addition of a Bacterial or an Archaeal inhibitor reduced N₂O fluxes from soils at 0-15 cm. These data show that nitrifying Archaea are present in these woody perennial soils, and in vitro studies suggest nitrifying Bacteria may be more important contributors to N₂O emissions than nitrifying Archaea at higher ammonia concentrations.
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/68308
note: ABUNDANCE OF AMMONIA-OXIDIZING ARCHAEA AND BACTERIA AND THEIR CONTRIBUTION TO NITROUS OXIDE EMISSIONS IN WOODY PERENNIAL CROPPING SYSTEMS by GEETKAMAL KAUR HANS B.Sc. (Honours), The University of British Columbia, 2014 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE COLLEGE OF GRADUATE STUDIES (Biochemistry and Molecular Biology) THE UNIVERSITY OF BRITISH COLUMBIA (Okanagan) January 2019 © Geetkamal Kaur Hans, 2019 ii The following individuals certify that they have read, and recommend to the College of Graduate Studies for acceptance, a thesis/dissertation entitled: ABUNDANCE OF AMMONIA-OXIDIZING ARCHAEA AND BACTERIA AND THEIR CONTRIBUTION TO NITROUS OXIDE EMISSIONS IN WOODY PERENNIAL CROPPING SYSTEMS submitted by Geetkamal Kaur Hans in partial fulfillment of the requirements of the degree of Master of Science Dr. Louise Nelson, Biology Department, Irving K. Barber School of Arts and Sciences Supervisor Dr. Craig Nichol, Earth and Environmental Sciences Department, Irving K. Barber School of Arts and Sciences Supervisory Committee Member Dr. Richard Plunkett, Biology Department, Irving K. Barber School of Arts and Sciences Supervisory Committee Member Dr. David Scott, Earth and Environmental Sciences Department, Irving K. Barber School of Arts and Sciences University Examiner iii Abstract Nitrification is one of the processes responsible for the emissions of nitrous oxide (N2O), an ozone-depleting greenhouse gas, from agricultural soil. In the first step of nitrification, catalyzed by the enzyme ammonia monooxygenase, ammonia is converted into hydroxylamine which further chemically decomposes into N2O. The contribution of nitrifying Archaeal species to N2O emissions in woody perennial cropping systems is not well understood. The first study reported here examined the effect of nitrogen application, mulch and soil depth on abundances of nitrifying Archaea and Bacteria, and total Archaea and Bacteria in an appl…
has type: Thesis/Dissertation
date issued: 2019-02
is shown at: 10.14288/1.0376218
language: eng
degree discipline: Biochemistry and Molecular Biology
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/68308