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dc.contributor.authorVonnahme, Tobias
dc.contributor.authorKlausen, Line
dc.contributor.authorBank, R.M.
dc.contributor.authorMichellod, D.
dc.contributor.authorLavik, G.
dc.contributor.authorDietrich, Ulrike
dc.contributor.authorGradinger, Rolf Rudolf
dc.date.accessioned2022-12-19T13:53:17Z
dc.date.available2022-12-19T13:53:17Z
dc.date.issued2022-09-30
dc.description.abstractThe polar night has recently received increased attention as a surprisingly active biological season. Yet, polar night microbial ecology is a vastly understudied field. To identify the physical and biogeochemical parameters driving microbial activity over the dark season, we studied a sub-Arctic fjord system in northern Norway from autumn to early spring with detailed monthly sampling. We focused on the impact of mixing, terrestrial organic matter input and light on microbial ecosystem dynamics. Our study highlights strong differences in the key drivers between spring, autumn, and winter. The spring bloom started in March in a fully mixed water column, opposing the traditional critical depth hypothesis. Incident solar radiation was the key driver maximum Chlorophyll was reached in April. The onset of the autumn phytoplankton bloom was controlled by vertical mixing, causing nutrient upwelling and dilution of zooplankton grazers, which had their highest biomass during this time. According to the dilution-recoupling hypothesis grazer dilution reduced grazing stress and allowed the fall bloom formation. Mixing at that time was initiated by strong winds and reduced stratification as a consequence of freezing temperatures and lower freshwater runoff. During the light-limited polar night, the primary production was extremely low but bacteria continued growing on decaying algae, their exudates and also allochthonous organic matter. A melting event in January could have increased input of organic matter from land, supporting a mid-winter bacterial bloom. In conclusion, polar night biogeochemistry and microbial ecology was not only driven by light availability, but strongly affected by variability in reshwater discharge and allochthonous carbon input. With climate change freshwater discharge will increase in the Arctic, which will likely increase importance of the dynamics described in this study.en_US
dc.identifier.citationVonnahme, Klausen, Bank, Michellod, Lavik, Dietrich, Gradinger. Light and freshwater discharge drive the biogeochemistry and microbial ecology in a sub-Arctic fjord over the Polar night. Frontiers in Marine Science. 2022;9en_US
dc.identifier.cristinIDFRIDAID 2093449
dc.identifier.doi10.3389/fmars.2022.915192
dc.identifier.issn2296-7745
dc.identifier.urihttps://hdl.handle.net/10037/27863
dc.language.isoengen_US
dc.publisherFrontiers Mediaen_US
dc.relation.journalFrontiers in Marine Science
dc.relation.projectIDinfo:eu-repo/grantAgreement/EC/H2020/869154/Norway/The future of Arctic coastal ecosystems - Identifying transitions in fjord systems and adjacent coastal areas/FACE-IT/en_US
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2022 The Author(s)en_US
dc.rights.urihttps://creativecommons.org/licenses/by/4.0en_US
dc.rightsAttribution 4.0 International (CC BY 4.0)en_US
dc.titleLight and freshwater discharge drive the biogeochemistry and microbial ecology in a sub-Arctic fjord over the Polar nighten_US
dc.type.versionpublishedVersionen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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Attribution 4.0 International (CC BY 4.0)
Med mindre det står noe annet, er denne innførselens lisens beskrevet som Attribution 4.0 International (CC BY 4.0)