Asynchronous Accumulation of Organic Carbon and Nitrogen in the Atlantic Gateway to the Arctic Ocean
Nitrogen (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...
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ftdoajarticles:oai:doaj.org/article:8409570b07784c769f0804554aefd565 2023-05-15T14:54:28+02:00 Asynchronous Accumulation of Organic Carbon and Nitrogen in the Atlantic Gateway to the Arctic Ocean Maria L. Paulsen Lena Seuthe Marit Reigstad Aud Larsen Mattias R. Cape Maria Vernet 2018-11-01T00:00:00Z https://doi.org/10.3389/fmars.2018.00416 https://doaj.org/article/8409570b07784c769f0804554aefd565 EN eng Frontiers Media S.A. https://www.frontiersin.org/article/10.3389/fmars.2018.00416/full https://doaj.org/toc/2296-7745 2296-7745 doi:10.3389/fmars.2018.00416 https://doaj.org/article/8409570b07784c769f0804554aefd565 Frontiers in Marine Science, Vol 5 (2018) particulate and dissolved organic matter nitrogen pools dissolved primary production high latitude ecosystems marginal ice zone Svalbard Science Q General. Including nature conservation geographical distribution QH1-199.5 article 2018 ftdoajarticles https://doi.org/10.3389/fmars.2018.00416 2022-12-31T12:20:18Z Nitrogen (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. Article in Journal/Newspaper Arctic Arctic Ocean Phytoplankton Svalbard Directory of Open Access Journals: DOAJ Articles Arctic Arctic Ocean Svalbard Frontiers in Marine Science 5 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
particulate and dissolved organic matter nitrogen pools dissolved primary production high latitude ecosystems marginal ice zone Svalbard Science Q General. Including nature conservation geographical distribution QH1-199.5 |
spellingShingle |
particulate and dissolved organic matter nitrogen pools dissolved primary production high latitude ecosystems marginal ice zone Svalbard Science Q General. Including nature conservation geographical distribution QH1-199.5 Maria L. Paulsen Lena Seuthe Marit Reigstad Aud Larsen Mattias R. Cape Maria Vernet Asynchronous Accumulation of Organic Carbon and Nitrogen in the Atlantic Gateway to the Arctic Ocean |
topic_facet |
particulate and dissolved organic matter nitrogen pools dissolved primary production high latitude ecosystems marginal ice zone Svalbard Science Q General. Including nature conservation geographical distribution QH1-199.5 |
description |
Nitrogen (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. |
format |
Article in Journal/Newspaper |
author |
Maria L. Paulsen Lena Seuthe Marit Reigstad Aud Larsen Mattias R. Cape Maria Vernet |
author_facet |
Maria L. Paulsen Lena Seuthe Marit Reigstad Aud Larsen Mattias R. Cape Maria Vernet |
author_sort |
Maria L. Paulsen |
title |
Asynchronous Accumulation of Organic Carbon and Nitrogen in the Atlantic Gateway to the Arctic Ocean |
title_short |
Asynchronous Accumulation of Organic Carbon and Nitrogen in the Atlantic Gateway to the Arctic Ocean |
title_full |
Asynchronous Accumulation of Organic Carbon and Nitrogen in the Atlantic Gateway to the Arctic Ocean |
title_fullStr |
Asynchronous Accumulation of Organic Carbon and Nitrogen in the Atlantic Gateway to the Arctic Ocean |
title_full_unstemmed |
Asynchronous Accumulation of Organic Carbon and Nitrogen in the Atlantic Gateway to the Arctic Ocean |
title_sort |
asynchronous accumulation of organic carbon and nitrogen in the atlantic gateway to the arctic ocean |
publisher |
Frontiers Media S.A. |
publishDate |
2018 |
url |
https://doi.org/10.3389/fmars.2018.00416 https://doaj.org/article/8409570b07784c769f0804554aefd565 |
geographic |
Arctic Arctic Ocean Svalbard |
geographic_facet |
Arctic Arctic Ocean Svalbard |
genre |
Arctic Arctic Ocean Phytoplankton Svalbard |
genre_facet |
Arctic Arctic Ocean Phytoplankton Svalbard |
op_source |
Frontiers in Marine Science, Vol 5 (2018) |
op_relation |
https://www.frontiersin.org/article/10.3389/fmars.2018.00416/full https://doaj.org/toc/2296-7745 2296-7745 doi:10.3389/fmars.2018.00416 https://doaj.org/article/8409570b07784c769f0804554aefd565 |
op_doi |
https://doi.org/10.3389/fmars.2018.00416 |
container_title |
Frontiers in Marine Science |
container_volume |
5 |
_version_ |
1766326195920568320 |