Exploring gene expression responses of marine bacteria to environmental factors
Bacterioplankton are abundant in marine ecosystems, where they as “masters of transformation” of dissolved organic matter (DOM) are important for energy fluxes and biogeochemical cycles. However, the performance of bacteria in a changing marine environment influenced by anthropogenic activities is p...
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Linnéuniversitetet, Institutionen för biologi och miljö (BOM)
2019
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ftlinnaeusuniv:oai:DiVA.org:lnu-90261 2023-05-15T17:50:12+02:00 Exploring gene expression responses of marine bacteria to environmental factors Osbeck, Christofer 2019 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-90261 eng eng Linnéuniversitetet, Institutionen för biologi och miljö (BOM) Växjö Linnaeus University Dissertations 371/2019 orcid:0000-0001-6866-8881 http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-90261 urn:isbn:978-91-89081-19-2 urn:isbn:978-91-89081-20-8 info:eu-repo/semantics/openAccess Baltic Sea dissolved organic matter model bacteria ocean acidification organic pollutants river loadings transcriptomics Ecology Ekologi Doctoral thesis, comprehensive summary info:eu-repo/semantics/doctoralThesis text 2019 ftlinnaeusuniv 2022-11-03T15:55:43Z Bacterioplankton are abundant in marine ecosystems, where they as “masters of transformation” of dissolved organic matter (DOM) are important for energy fluxes and biogeochemical cycles. However, the performance of bacteria in a changing marine environment influenced by anthropogenic activities is poorly understood. In this thesis, I did experiments with model bacteria and natural assemblages of bacteria, using microbiology methods combined with modern molecular tools, to investigate responses of marine bacteria to changes in environmental conditions like ocean acidification, organic pollution and organic matter released by phytoplankton. Experiments with a model gammaproteobacterium demonstrated that bacteria in stationary phase showed little responses to organic pollutants, whereas pollutants caused decreased bacterial growth and had a broad physiological impact on actively growing bacteria (as deduced from gene expression analysis). In an experiment with two distantly related marine model bacteria, we identified several important bacterial mechanisms, such as uptake of macromolecules and phosphonates, by which bacteria respond when exposed to DOM produced by photosynthetic dinoflagellates. Using natural bacterial communities in a Baltic Sea mesocosm experiment with the addition of river water from a forested or an agriculture influenced catchment area, we showed important interactions between river water type and the development of phytoplankton blooms that caused different bacterial gene expression activities. In the fourth set of experiments, marine bacterial communities were subjected to elevated CO2, to mimic ocean acidification, under high and low nutrient conditions in a mesocosm study. We found increased bacterial gene expression activity focused on maintaining pH homeostasis, but only under low nutrient conditions, indicating that bacteria focus on cell maintenance instead of growth when challenged by lowered pH. Finally, in a computational analysis, we compared genomes from yet uncultivated ... Doctoral or Postdoctoral Thesis Ocean acidification Linnaeus University Kalmar Växjö: Publications (DiVA) |
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Linnaeus University Kalmar Växjö: Publications (DiVA) |
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ftlinnaeusuniv |
language |
English |
topic |
Baltic Sea dissolved organic matter model bacteria ocean acidification organic pollutants river loadings transcriptomics Ecology Ekologi |
spellingShingle |
Baltic Sea dissolved organic matter model bacteria ocean acidification organic pollutants river loadings transcriptomics Ecology Ekologi Osbeck, Christofer Exploring gene expression responses of marine bacteria to environmental factors |
topic_facet |
Baltic Sea dissolved organic matter model bacteria ocean acidification organic pollutants river loadings transcriptomics Ecology Ekologi |
description |
Bacterioplankton are abundant in marine ecosystems, where they as “masters of transformation” of dissolved organic matter (DOM) are important for energy fluxes and biogeochemical cycles. However, the performance of bacteria in a changing marine environment influenced by anthropogenic activities is poorly understood. In this thesis, I did experiments with model bacteria and natural assemblages of bacteria, using microbiology methods combined with modern molecular tools, to investigate responses of marine bacteria to changes in environmental conditions like ocean acidification, organic pollution and organic matter released by phytoplankton. Experiments with a model gammaproteobacterium demonstrated that bacteria in stationary phase showed little responses to organic pollutants, whereas pollutants caused decreased bacterial growth and had a broad physiological impact on actively growing bacteria (as deduced from gene expression analysis). In an experiment with two distantly related marine model bacteria, we identified several important bacterial mechanisms, such as uptake of macromolecules and phosphonates, by which bacteria respond when exposed to DOM produced by photosynthetic dinoflagellates. Using natural bacterial communities in a Baltic Sea mesocosm experiment with the addition of river water from a forested or an agriculture influenced catchment area, we showed important interactions between river water type and the development of phytoplankton blooms that caused different bacterial gene expression activities. In the fourth set of experiments, marine bacterial communities were subjected to elevated CO2, to mimic ocean acidification, under high and low nutrient conditions in a mesocosm study. We found increased bacterial gene expression activity focused on maintaining pH homeostasis, but only under low nutrient conditions, indicating that bacteria focus on cell maintenance instead of growth when challenged by lowered pH. Finally, in a computational analysis, we compared genomes from yet uncultivated ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Osbeck, Christofer |
author_facet |
Osbeck, Christofer |
author_sort |
Osbeck, Christofer |
title |
Exploring gene expression responses of marine bacteria to environmental factors |
title_short |
Exploring gene expression responses of marine bacteria to environmental factors |
title_full |
Exploring gene expression responses of marine bacteria to environmental factors |
title_fullStr |
Exploring gene expression responses of marine bacteria to environmental factors |
title_full_unstemmed |
Exploring gene expression responses of marine bacteria to environmental factors |
title_sort |
exploring gene expression responses of marine bacteria to environmental factors |
publisher |
Linnéuniversitetet, Institutionen för biologi och miljö (BOM) |
publishDate |
2019 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-90261 |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_relation |
Linnaeus University Dissertations 371/2019 orcid:0000-0001-6866-8881 http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-90261 urn:isbn:978-91-89081-19-2 urn:isbn:978-91-89081-20-8 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766156858016399360 |