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dc.contributor.authorPaulsen, Maria Lund
dc.contributor.authorSeuthe, Lena
dc.contributor.authorReigstad, Marit
dc.contributor.authorLarsen, Aud
dc.contributor.authorCape, Matthias
dc.contributor.authorVernet, Maria
dc.PublishedPaulsen ML, Seuthe L, Reigstad M, Larsen A, Cape M, Vernet M. Asynchronous Accumulation of Organic Carbon and Nitrogen in the Atlantic Gateway to the Arctic Ocean. Frontiers in Marine Science. 2018;5:416eng
dc.description.abstractNitrogen (N) is the main limiting nutrient for biological production in the Arctic Ocean. While dissolved inorganic N (DIN) is well studied, the substantial pool of N bound in organic matter (OM) and its bioavailability in the system is rarely considered. Covering a full annual cycle, we here follow N and carbon (C) content in particulate (P) and dissolved (D) OM within the Atlantic water inflow to the Arctic Ocean. While particulate organic carbon (POC), particulate organic nitrogen (PON), and dissolved organic carbon (DOC) accumulated in the surface waters from January to May, the dissolved organic nitrogen (DON)-pool decreased substantially (Δ – 50 μg N L-1). The DON reduction was greater than the simultaneous reduction in DIN (Δ – 30 μg N L-1), demonstrating that DON is a valuable N-source supporting the growing biomass. While the accumulating POM had a C/N ratio close to Redfield, the asynchronous accumulation of C and N in the dissolved pool resulted in a drastic increase in the C/N ratio of dissolved organic molecules (DOM) during the spring bloom. This is likely due to a combination of the reduction in DON, and a high release of carbon-rich sugars from phytoplankton, as 32% of the spring primary production (PP) was dissolved. Our findings thus caution calculations of particulate PP from DIN drawdown. During post-bloom the DON pool increased threefold due to an enhanced microbial processing of OM and reduced phytoplankton production. The light absorption spectra of DOM revealed high absorption within the UV range during spring bloom indicating DOM with low molecular weight in this period. The absorption of DOM was generally lower in the winter months than in spring and summer. Our results demonstrate that the change in ecosystem function (i.e., phytoplankton species and activity, bacterial activity and grazing) in different seasons is associated with strong changes in the C/N ratios and optical character of DOM and underpin the essential role of DON for the production cycle in the Arctic.en_US
dc.rightsAttribution CC BYeng
dc.subjectparticulate and dissolved organic mattereng
dc.subjectnitrogen poolseng
dc.subjectdissolved primary productioneng
dc.subjecthigh latitude ecosystemseng
dc.subjectmarginal ice zoneeng
dc.subjectWest Spitsbergen Currenteng
dc.titleAsynchronous Accumulation of Organic Carbon and Nitrogen in the Atlantic Gateway to the Arctic Oceanen_US
dc.typePeer reviewed
dc.typeJournal article
dc.rights.holderCopyright 2018 The Author(s)en_US
dc.source.journalFrontiers in Marine Science
dc.relation.projectNorges forskningsråd: 226415

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