{"id":{"repo_id":"mit","oai_identifier":"oai:dspace.mit.edu:1721.1/103254"},"canonical_url":"https://search.dev.ndltd.org/etd/mit/oai:dspace.mit.edu:1721.1/103254","repository":{"repo_id":"mit","name":"MIT","base_url":"https://dspace.mit.edu/oai/request"},"display":{"title":"The biogeochemistry of lipid derived infochemical signals in the ocean","abstract":"The role of oxylipins in ocean biogeochemistry was investigated using microcosm amendment experiments, environmental lipidomics, and culture based studies. Oxylipins are a bioactive class of secondary metabolites produced by diatoms and other eukaryotic phytoplankton. Previous research has focused mainly on one class of oxylipins, polyunsaturated aldehydes (PUAs), and their impacts on copepods. And few studies have looked at the impacts of oxylipins in situ. Here I show that oxylipins have the potential to impact carbon flux attenuation, oxylipin production in situ is linked to diatom bloom decline and viruses, and oxylipins deter microzooplankton grazing. Sinking particles collected in the North Atlantic were determined to be hot spots for PUAs with concentrations in the micromolar range. Natural particle associated microbial communities exhibited a dose dependent response to PUAs. Stimulatory PUA concentrations ranged from 1-10 ptM, resulting in enhanced remineralization of organic matter by particle associated microbes. Thus, PUAs produced during bloom decline may lead to greater flux attenuation and nutrient recycling. A novel lipidomics approach was applied along a cruise track in the California Coastal System revealing that canonical diatom free fatty acids and oxylipins dominated the dissolved lipidome and oxylipin abundance was correlated with diatom bloom demise as assessed by phaeophytin and biogenic Si. RNA viruses were likely the cause of diatom bloom demise and may have induced oxylipin production. The link between viruses and oxylipins represents a new infochemical signaling pathway in the ocean. Many oxylipins that are novel to the marine environment were also identified. The dissolved lipidome was sampled during grazing experiments with the microzooplankton grazer Oxyrrhis marina and both wild type Phaeodactylum tricornutum and a chronically stressed, transgenic strain (PtNOA). Grazing was suppressed in the PtNOA treatments compared to the WT, likely due to upregulation of small unknown lipophilic molecules. This suggests that cellular stress and oxylipin production may deter microzooplankton grazing in the environment potentially altering the transfer of energy through the microbial food web. By employing interdisciplinary approaches, we have learned that oxylipins production in situ is linked to bloom decline and the bioactivity of these compounds has significant implications for ocean biogeochemical cycles.","abstract_html":"The role of oxylipins in ocean biogeochemistry was investigated using microcosm amendment experiments, environmental lipidomics, and culture based studies. Oxylipins are a bioactive class of secondary metabolites produced by diatoms and other eukaryotic phytoplankton. Previous research has focused mainly on one class of oxylipins, polyunsaturated aldehydes (PUAs), and their impacts on copepods. And few studies have looked at the impacts of oxylipins in situ. Here I show that oxylipins have the potential to impact carbon flux attenuation, oxylipin production in situ is linked to diatom bloom decline and viruses, and oxylipins deter microzooplankton grazing. Sinking particles collected in the North Atlantic were determined to be hot spots for PUAs with concentrations in the micromolar range. Natural particle associated microbial communities exhibited a dose dependent response to PUAs. Stimulatory PUA concentrations ranged from 1-10 ptM, resulting in enhanced remineralization of organic matter by particle associated microbes. Thus, PUAs produced during bloom decline may lead to greater flux attenuation and nutrient recycling. A novel lipidomics approach was applied along a cruise track in the California Coastal System revealing that canonical diatom free fatty acids and oxylipins dominated the dissolved lipidome and oxylipin abundance was correlated with diatom bloom demise as assessed by phaeophytin and biogenic Si. RNA viruses were likely the cause of diatom bloom demise and may have induced oxylipin production. The link between viruses and oxylipins represents a new infochemical signaling pathway in the ocean. Many oxylipins that are novel to the marine environment were also identified. The dissolved lipidome was sampled during grazing experiments with the microzooplankton grazer Oxyrrhis marina and both wild type Phaeodactylum tricornutum and a chronically stressed, transgenic strain (PtNOA). Grazing was suppressed in the PtNOA treatments compared to the WT, likely due to upregulation of small unknown lipophilic molecules. This suggests that cellular stress and oxylipin production may deter microzooplankton grazing in the environment potentially altering the transfer of energy through the microbial food web. By employing interdisciplinary approaches, we have learned that oxylipins production in situ is linked to bloom decline and the bioactivity of these compounds has significant implications for ocean biogeochemical cycles.","abstract_has_math":false,"creators":["Edwards, Bethanie Rachele"],"institution":"Massachusetts Institute of Technology","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Joint Program in Oceanography/Applied Ocean Science and Engineering.","school":null,"contributors":[],"advisors":["Benjamin A. S. Van Mooy."],"committee_chairs":[],"committee_members":[],"year":2016,"date_issued":"2016","date_published":"2016","updated_at":"2026-07-22T22:21:07Z","subjects":["Joint Program in Oceanography/Applied Ocean Science and Engineering.","Earth, Atmospheric, and Planetary Sciences.","Woods Hole Oceanographic Institution."],"languages":["eng"],"rights":["M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission."],"rights_urls":["http://dspace.mit.edu/handle/1721.1/7582"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/1721.1/103254","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Benjamin A. S. Van Mooy."]},{"key":"dc:contributor.department","label":"Department","values":["Joint Program in Oceanography/Applied Ocean Science and Engineering.","Massachusetts Institute of Technology. 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They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission."]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://dspace.mit.edu/handle/1721.1/7582"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/1721.1/103254"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Thesis: Ph. 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Here I show that oxylipins have the potential to impact carbon flux attenuation, oxylipin production in situ is linked to diatom bloom decline and viruses, and oxylipins deter microzooplankton grazing. Sinking particles collected in the North Atlantic were determined to be hot spots for PUAs with concentrations in the micromolar range. Natural particle associated microbial communities exhibited a dose dependent response to PUAs. Stimulatory PUA concentrations ranged from 1-10 ptM, resulting in enhanced remineralization of organic matter by particle associated microbes. Thus, PUAs produced during bloom decline may lead to greater flux attenuation and nutrient recycling. A novel lipidomics approach was applied along a cruise track in the California Coastal System revealing that canonical diatom free fatty acids and oxylipins dominated the dissolved lipidome and oxylipin abundance was correlated with diatom bloom demise as assessed by phaeophytin and biogenic Si. RNA viruses were likely the cause of diatom bloom demise and may have induced oxylipin production. The link between viruses and oxylipins represents a new infochemical signaling pathway in the ocean. Many oxylipins that are novel to the marine environment were also identified. The dissolved lipidome was sampled during grazing experiments with the microzooplankton grazer Oxyrrhis marina and both wild type Phaeodactylum tricornutum and a chronically stressed, transgenic strain (PtNOA). Grazing was suppressed in the PtNOA treatments compared to the WT, likely due to upregulation of small unknown lipophilic molecules. This suggests that cellular stress and oxylipin production may deter microzooplankton grazing in the environment potentially altering the transfer of energy through the microbial food web. By employing interdisciplinary approaches, we have learned that oxylipins production in situ is linked to bloom decline and the bioactivity of these compounds has significant implications for ocean biogeochemical cycles."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Ph. D."]},{"key":"dc:title","label":"Title","values":["The biogeochemistry of lipid derived infochemical signals in the ocean"]}]}],"canonical_facts":{"dc:contributor.advisor":["Benjamin A. S. Van Mooy."],"dc:contributor.department":["Joint Program in Oceanography/Applied Ocean Science and Engineering.","Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences.","Woods Hole Oceanographic Institution."],"dc:contributor.other":["Woods Hole Oceanographic Institution."],"dc:creator":["Edwards, Bethanie Rachele"],"dc:date.accessioned":["2016-06-22T17:52:40Z"],"dc:date.available":["2016-06-22T17:52:40Z"],"dc:date.issued":["2016"],"dc:description":["Thesis: Ph. 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Sinking particles collected in the North Atlantic were determined to be hot spots for PUAs with concentrations in the micromolar range. Natural particle associated microbial communities exhibited a dose dependent response to PUAs. Stimulatory PUA concentrations ranged from 1-10 ptM, resulting in enhanced remineralization of organic matter by particle associated microbes. Thus, PUAs produced during bloom decline may lead to greater flux attenuation and nutrient recycling. A novel lipidomics approach was applied along a cruise track in the California Coastal System revealing that canonical diatom free fatty acids and oxylipins dominated the dissolved lipidome and oxylipin abundance was correlated with diatom bloom demise as assessed by phaeophytin and biogenic Si. RNA viruses were likely the cause of diatom bloom demise and may have induced oxylipin production. The link between viruses and oxylipins represents a new infochemical signaling pathway in the ocean. Many oxylipins that are novel to the marine environment were also identified. The dissolved lipidome was sampled during grazing experiments with the microzooplankton grazer Oxyrrhis marina and both wild type Phaeodactylum tricornutum and a chronically stressed, transgenic strain (PtNOA). Grazing was suppressed in the PtNOA treatments compared to the WT, likely due to upregulation of small unknown lipophilic molecules. This suggests that cellular stress and oxylipin production may deter microzooplankton grazing in the environment potentially altering the transfer of energy through the microbial food web. By employing interdisciplinary approaches, we have learned that oxylipins production in situ is linked to bloom decline and the bioactivity of these compounds has significant implications for ocean biogeochemical cycles."],"dc:description.degree":["Ph. D."],"dc:identifier.uri":["http://hdl.handle.net/1721.1/103254"],"dc:language.iso":["eng"],"dc:publisher":["Massachusetts Institute of Technology"],"dc:rights":["M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission."],"dc:rights.uri":["http://dspace.mit.edu/handle/1721.1/7582"],"dc:subject":["Joint Program in Oceanography/Applied Ocean Science and Engineering.","Earth, Atmospheric, and Planetary Sciences.","Woods Hole Oceanographic Institution."],"dc:title":["The biogeochemistry of lipid derived infochemical signals in the ocean"],"dc:type":["Thesis"]},"updated_at":"2026-07-22T22:21:07Z"}