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dc.contributor.advisorSvenning, Mette M.
dc.contributor.authorCarrier, Vincent
dc.date.accessioned2021-11-12T12:31:18Z
dc.date.available2021-11-12T12:31:18Z
dc.date.issued2021-11-29
dc.description.abstractCold seeps are locations on the seafloor where CH<sub>4</sub> migrates from reservoirs below sediments towards the atmosphere, sustaining thereby a high microbial and macrofaunal biomass and a diversity contrasting from the surrounding seafloor. The oxidation of methane and sulphide are typically the main sources of primary productivity of these ecosystems and have therefore gained a particular attention in the global oceans. Yet, despite the ubiquitous presence of these seeping sites and the presence of gas hydrates in the Arctic Ocean and its adjacent shelves, the impact of methane on benthic and pelagic microbial communities in this region have remained limited. Recently, five gas hydrate bearing mounds with ongoing methane seeping activity were discovered south of Svalbard, in the northern Barents Sea. In this PhD project, I studied changes in the structure of microbial communities, including both prokaryotes and eukaryotes, and geochemical profiles at these mounds to highlight key microbial groups and to provide insights on their ecological roles. Different niches were addressed, including: deep anaerobic sediments (Paper I and II); niches at the sediment surface at gas flare locations and within bacterial mats and siboglinid fields (Paper III); and above gas flares in the shallow shelf water column (Paper IV). The microbial biodiversity and the structure of communities were successfully identified for each of the habitats listed above. Our investigations revealed a microbial composition similar to other cold seeps: a predominance of archaeal anaerobic methanotrophs (ANME) and sulphate-reducing bacteria (SRB) in CH<sub>4</sub>-rich sediments, a higher abundance of methane oxidizing bacteria associated to the Methylococcales in the surface sediments and water column; and a co-occurrence of other commonly found prokaryotic groups. Yet, uncommon biological traits were also uncovered at these methane seeping sites: the anaerobic oxidation of methane was merely only driven by ANME-1 without the co-occurrence of a specific SRB clade; an abundant methanotroph with little genetic similarity in databases was detected; and a strong niche differentiation of sulphide-oxidizing bacteria within the different bacterial mats. This project has thereby extended our knowledge on the microbial biodiversity at Arctic cold seeps and opened further future research perspective toward microbial activity and metabolism at these high latitudes.en_US
dc.description.doctoraltypeph.d.en_US
dc.description.popularabstractCold seeps are locations on the seafloor where methane gas migrates from sediment reservoirs below. Oxidation of the methane, and subsequently of its sub products, are typically the main sources of primary productivity of these ecosystems resulting in biodiversity on the seafloor. Yet, despite the ubiquitous presence of these seeping sites in the Arctic marine ecosystem the impact of the methane on microbial biodiversity and activity in the water column and seabed of this region have remained limited. Recently, five cold seeps with ongoing methane seeping activity were discovered south of Svalbard. In this PhD project, I studied the structure of microbial communities and the geochemical profiles at these cold seeps to understand their ecological roles. Different biodiversity niches were addressed. These niches included, deep anaerobic sediments, the sediment surface at gas flares and within bacterial mats and tubeworm fields, The study also included gas flares in the shallow shelf water column. The microbial biodiversity were successfully identified for each of the habitats listed above. Our investigations revealed a microbial composition similar to cold seeps other places in the world. Yet, unique biological traits were also identified at these Arctic methane seeping sites, such as a key microbe with little genetic similarity to previous studies. This PhD project has thereby extended our knowledge on the microbial biodiversity at Arctic cold seeps and given a platform for future research in marine microbial ecology at these high latitudes.en_US
dc.description.sponsorshipThis Thesis was funded by the Research Council of Norway through the Centre of Excellence for Arctic Gas Hydrate, Environment, and Climate (grant number: 223259), and by the Faculty of Biosciences, Fisheries and Economics.en_US
dc.identifier.isbn978-82-8266-206-2
dc.identifier.urihttps://hdl.handle.net/10037/22978
dc.language.isoengen_US
dc.publisherUiT The Arctic University of Norwayen_US
dc.publisherUiT Norges arktiske universiteten_US
dc.relation.haspart<p>Paper I: Carrier, V., Svenning, M.M., Gründger, F., Niemann, H., Dessandier, P.A., Panieri, G. & Kalenitchenko, D. (2020). The Impact of Methane on Microbial Communities at Marine Arctic Gas Hydrate Bearing Sediment. <i>Frontiers in Microbiology, 11</i>, 1932. Also available in Munin at <a href=https://hdl.handle.net/10037/19507>https://hdl.handle.net/10037/19507</a>. <p>Paper II: Gründger, F., Carrier, V., Svenning, M.M., Panieri, G., Vonnahme, T.R., Klasek, S. & Niemann, H. (2019). Methane-fuelled biofilms predominantly composed of methanotrophic ANME-1 in Arctic gas hydrate-related sediments. <i>Scientific Reports, 9</i>, 9725. Also available in Munin at <a href=https://hdl.handle.net/10037/16225>https://hdl.handle.net/10037/16225</a>. <p>Paper III: Carrier V., Svenning, M.M., Niemann, H., Gründger, F.F. & Kalenitchenko, D. Niche differentiation of prokaryotic communities and aerobic methanotrophs in surface sediments of an Arctic cold seep. (Manuscript). <p>Paper IV: Gründger, F., Probandt, D., Knittel, K., Carrier, V., Kalenitchenko, D., Silyakova, A., … Niemann, H. (2021). Seasonal shifts of microbial methane oxidation in Arctic shelf waters above gas seeps. <i>Limnology and Oceanography, 66</i>(5), 1896-1914. Also available in Munin at <a href=https://hdl.handle.net/10037/21556>https://hdl.handle.net/10037/21556</a>.en_US
dc.relation.projectIDinfo:eu-repo/grantAgreement/RCN/SFF/223259/Norway/Centre for Arctic Gas Hydrate, Environment and Climate/CAGE/en_US
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2021 The Author(s)
dc.subject.courseIDDOKTOR-002
dc.subjectVDP::Mathematics and natural science: 400::Basic biosciences: 470::General microbiology: 472en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Basale biofag: 470::Generell mikrobiologi: 472en_US
dc.subjectVDP::Mathematics and natural science: 400::Basic biosciences: 470::Genetics and genomics: 474en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Basale biofag: 470::Genetikk og genomikk: 474en_US
dc.subjectVDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Marinbiologi: 497en_US
dc.subjectVDP::Mathematics and natural science: 400::Zoology and botany: 480::Ecology: 488en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Økologi: 488en_US
dc.titleMicrobial community structure associated to Arctic cold seepsen_US
dc.typeDoctoral thesisen_US
dc.typeDoktorgradsavhandlingen_US


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