Assimilation of carbon and nitrogen by microbial mats from alkaline soda lakes

Liu, Yihua

Assimilation of carbon and nitrogen by microbial mats from alkaline soda lakes

dc.contributor.advisor	Strous, Marc
dc.contributor.author	Liu, Yihua
dc.contributor.committeemember	Hubert, Casey R J
dc.contributor.committeemember	Tutolo, Benjamin M
dc.contributor.committeemember	Hu, Jinguang
dc.date	Spring Convocation
dc.date.accessioned	2023-02-11T00:32:02Z
dc.date.embargolift	2023-02-22
dc.date.issued	2020-11-19
dc.description.abstract	Background:Soda lakes are extreme terrestrial ecosystems characterized by high pH, alkalinity, and sodium carbonate concentration. Despite the extreme environment, soda lakes host diverse microbial communities with high primary productivity, carried out by fast-growing phototrophic microbes such as cyanobacteria. In Goodenough Lake, a soda lake on the Cariboo Plateau in BC Canada, carbon isotope analysis indicated that the photosynthetic rate but not bicarbonate availability controlled carbon dioxide assimilation. However, the roles of individual cyanobacteria populations in carbon fixation remain unknown. Despite the rapid growth of microbial mat communities, common nitrogen sources, ammonium and nitrate, were detected only occasionally and in trace amounts in lake water. Mat communities may use alternative nitrogen sources like urea and dinitrogen gas as enzymes for urea assimilation and dinitrogen fixation were highly expressed.Objective:The objective is to measure carbon and nitrogen assimilation by microbial populations in mat communities.Approaches:Incubation of microbial mats from Goodenough Lake with heavy stable isotope labelled bicarbonate, and nitrogen sources, followed by isotope ratio mass spectrometry and proteomics.Results and conclusions:Over 90 different microbial populations were detected in microbial mat communities using proteomics. The sampled mat microbial communities were different from each other, even if samples were close together, but the most abundant populations were the same across samples. The two most abundant cyanobacterial populations exhibited different carbon fixation dynamics, and their abundance was negatively correlated, suggesting that they occupy different ecological niches. Among nitrogen sources, urea was consumed at the highest rate, followed by ammonia. The nitrate consumption rate was much lower, and the fixation of nitrogen was not detected. Urea was consumed mainly during the day. Rates for nitrate and ammonia consumption were similar during the day and the night.
dc.identifier.citation	Liu, Y. (2020). Assimilation of carbon and nitrogen by microbial mats from alkaline soda lakes (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.
dc.identifier.uri	http://hdl.handle.net/1880/115848
dc.identifier.uri	https://dx.doi.org/10.11575/PRISM/40742
dc.language.iso	en	en
dc.language.iso	English
dc.publisher.faculty	Graduate Studies	en
dc.publisher.faculty	Science
dc.publisher.institution	University of Calgary	en
dc.rights	University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.	en
dc.subject.classification	Environmental Sciences
dc.subject.classification	Biogeochemistry
dc.subject.classification	Geology
dc.subject.classification	Biology--Ecology
dc.subject.classification	Biology--Bioinformatics
dc.subject.classification	Biology--Microbiology
dc.title	Assimilation of carbon and nitrogen by microbial mats from alkaline soda lakes
dc.type	master thesis
thesis.degree.discipline	Geoscience
thesis.degree.grantor	University of Calgary	en
thesis.degree.grantor	University of Calgary
thesis.degree.name	Master of Science (MSc)