Marine microbial intact polar diacylglycerolipids and their application in the study of nutrient stress and bacterial production

dc.contributor.author Popendorf, Kimberly J.
dc.coverage.spatial Sargasso Sea
dc.coverage.spatial North Pacific
dc.coverage.spatial North Atlantic
dc.coverage.spatial Mediterranean Sea
dc.date.accessioned 2012-12-21T15:56:32Z
dc.date.available 2012-12-21T15:56:32Z
dc.date.issued 2013-02
dc.description Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2013 en_US
dc.description.abstract Intact polar diacylglycerolipids (IP-DAGs) were used to study microbial dynamics in the surface ocean. IP-DAGs from surface ocean seawater were quantified using high performance liquid chromatography-mass spectrometry (HPLC-MS), after first developing a sensitive, high throughput molecular ion independent triple quadrupole MS method for quantification. Using this analytical technique I examined the distribution of the nine most abundant classes of IPDAGs across the Mediterranean, and found that phospholipids as a percent of total IP-DAGs correlated with phosphate concentration. Furthermore, phospholipids were a higher percent of total particulate phosphorus where phosphate was higher, ranging from 1-14%. Thus IP-DAGs can play not only a significant but also a dynamic role in defining planktonic nutrient needs and cellular C:N:P ratios in the environment. Additionally, microcosm incubations were amended with phosphate and ammonium, and in the course of several days this elicited a shift in the ratios of IP-DAGs. This study was the first to demonstrate the dynamic response of membrane lipid composition to changes in nutrients in a natural, mixed planktonic community, and indicated that the change in IP-DAG ratios in response to changing nutrients may be a useful indicator of microbial nutrient stress. In the surface waters of the western North Atlantic I used three experimental approaches to identify the microbial sources of the nine most abundant classes of IP-DAGs. Phytoplankton are the primary source of one class of sulfolipid, sulfoquinovosyldiacylglycerol, and one class of betaine lipid, diacylglyceryl-trimethyl-homoserine, while heterotrophic bacteria are the dominant source of the phospholipids phosphatidylglycerol and phosphatidylethanolamine. In regrowth experiments in the Sargasso Sea and the North Pacific I demonstrated that phospholipid specific production rate is representative of heterotrophic bacterial cell specific growth rate. I measured phospholipid specific production rate and bacterial production rate using uptake of 3H-leucine (3H-Leu) and 3H-thymidine (3H-TdR) across the North Atlantic, across the Mediterranean, and in the North Pacific subtropical gyre. I found that phospholipid specific production rates estimate heterotrophic bacterial cell specific growth rates that are on the order of 1 per day, an order of magnitude faster than cell specific growth rates suggested by uptake of 3H-Leu and 3H-TdR. en_US
dc.description.sponsorship This research was supported by a National Science Foundation Graduate Research Fellowship, a National Defense Science and Engineering Graduate Fellowship, and grants from the U.S. Office of Naval Research (N00014-09-1-0091 and N00014-06-1-0134) and the U.S. National Science Foundation (OCE-1031143, OCE-1029687, and OCE-0646944). en_US
dc.format.mimetype application/pdf
dc.identifier.citation Popendorf, K. J. (2013). Marine microbial intact polar diacylglycerolipids and their application in the study of nutrient stress and bacterial production [Doctoral thesis, Massachusetts Institute of Technology and Woods Hole Oceanographic Institution]. Woods Hole Open Access Server. https://doi.org/10.1575/1912/5663
dc.identifier.doi 10.1575/1912/5663
dc.identifier.uri https://hdl.handle.net/1912/5663
dc.language.iso en_US en_US
dc.publisher Massachusetts Institute of Technology and Woods Hole Oceanographic Institution en_US
dc.relation.ispartofseries WHOI Theses en_US
dc.subject Microbial ecology en_US
dc.subject Microbiological chemistry en_US
dc.subject Atlantic Exploer (Ship) Cruise BV39 en_US
dc.subject Oceanus (Ship : 1975-) Cruise OC443 en_US
dc.subject L'Atalante (Ship) BOUM Cruise en_US
dc.subject Kilo Moana (Ship) Cruise KM1013 en_US
dc.title Marine microbial intact polar diacylglycerolipids and their application in the study of nutrient stress and bacterial production en_US
dc.type Thesis en_US
dspace.entity.type Publication
relation.isAuthorOfPublication 709dd009-8b9f-4071-bd91-abd03751b0de
relation.isAuthorOfPublication.latestForDiscovery 709dd009-8b9f-4071-bd91-abd03751b0de
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