The fate of fixed nitrogen in marine sediments with low organic loading: an in situ study
Over the last decades, the impact of human activities on the global nitrogen (N) cycle has drastically increased. Consequently, benthic N cycling has mainly been studied in anthropogenically impacted estuaries and coasts, while in oligotrophic systems its understanding is still scarce. Here we repor...
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ftdoajarticles:oai:doaj.org/article:b941dca53fbf499885cb80c962dc27c7 2023-05-15T15:17:29+02:00 The fate of fixed nitrogen in marine sediments with low organic loading: an in situ study S. Bonaglia A. Hylén J. E. Rattray M. Y. Kononets N. Ekeroth P. Roos B. Thamdrup V. Brüchert P. O. J. Hall 2017-01-01T00:00:00Z https://doi.org/10.5194/bg-14-285-2017 https://doaj.org/article/b941dca53fbf499885cb80c962dc27c7 EN eng Copernicus Publications http://www.biogeosciences.net/14/285/2017/bg-14-285-2017.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-14-285-2017 https://doaj.org/article/b941dca53fbf499885cb80c962dc27c7 Biogeosciences, Vol 14, Iss 2, Pp 285-300 (2017) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2017 ftdoajarticles https://doi.org/10.5194/bg-14-285-2017 2022-12-31T11:34:17Z Over the last decades, the impact of human activities on the global nitrogen (N) cycle has drastically increased. Consequently, benthic N cycling has mainly been studied in anthropogenically impacted estuaries and coasts, while in oligotrophic systems its understanding is still scarce. Here we report on benthic solute fluxes and on rates of denitrification, anammox, and dissimilatory nitrate reduction to ammonium (DNRA) studied by in situ incubations with benthic chamber landers during two cruises to the Gulf of Bothnia (GOB), a cold, oligotrophic basin located in the northern part of the Baltic Sea. Rates of N burial were also inferred to investigate the fate of fixed N in these sediments. Most of the total dissolved fixed nitrogen (TDN) diffusing to the water column was composed of organic N. Average rates of dinitrogen (N 2 ) production by denitrification and anammox (range: 53–360 µmol N m −2 day −1 ) were comparable to those from Arctic and subarctic sediments worldwide (range: 34–344 µmol N m −2 day −1 ). Anammox accounted for 18–26 % of the total N 2 production. Absence of free hydrogen sulfide and low concentrations of dissolved iron in sediment pore water suggested that denitrification and DNRA were driven by organic matter oxidation rather than chemolithotrophy. DNRA was as important as denitrification at a shallow, coastal station situated in the northern Bothnian Bay. At this pristine and fully oxygenated site, ammonium regeneration through DNRA contributed more than one-third to the TDN efflux and accounted, on average, for 45 % of total nitrate reduction. At the offshore stations, the proportion of DNRA in relation to denitrification was lower (0–16 % of total nitrate reduction). Median value and range of benthic DNRA rates from the GOB were comparable to those from the southern and central eutrophic Baltic Sea and other temperate estuaries and coasts in Europe. Therefore, our results contrast with the view that DNRA is negligible in cold and well-oxygenated sediments with low organic carbon ... Article in Journal/Newspaper Arctic Subarctic Directory of Open Access Journals: DOAJ Articles Arctic Biogeosciences 14 2 285 300 |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
spellingShingle |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 S. Bonaglia A. Hylén J. E. Rattray M. Y. Kononets N. Ekeroth P. Roos B. Thamdrup V. Brüchert P. O. J. Hall The fate of fixed nitrogen in marine sediments with low organic loading: an in situ study |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
Over the last decades, the impact of human activities on the global nitrogen (N) cycle has drastically increased. Consequently, benthic N cycling has mainly been studied in anthropogenically impacted estuaries and coasts, while in oligotrophic systems its understanding is still scarce. Here we report on benthic solute fluxes and on rates of denitrification, anammox, and dissimilatory nitrate reduction to ammonium (DNRA) studied by in situ incubations with benthic chamber landers during two cruises to the Gulf of Bothnia (GOB), a cold, oligotrophic basin located in the northern part of the Baltic Sea. Rates of N burial were also inferred to investigate the fate of fixed N in these sediments. Most of the total dissolved fixed nitrogen (TDN) diffusing to the water column was composed of organic N. Average rates of dinitrogen (N 2 ) production by denitrification and anammox (range: 53–360 µmol N m −2 day −1 ) were comparable to those from Arctic and subarctic sediments worldwide (range: 34–344 µmol N m −2 day −1 ). Anammox accounted for 18–26 % of the total N 2 production. Absence of free hydrogen sulfide and low concentrations of dissolved iron in sediment pore water suggested that denitrification and DNRA were driven by organic matter oxidation rather than chemolithotrophy. DNRA was as important as denitrification at a shallow, coastal station situated in the northern Bothnian Bay. At this pristine and fully oxygenated site, ammonium regeneration through DNRA contributed more than one-third to the TDN efflux and accounted, on average, for 45 % of total nitrate reduction. At the offshore stations, the proportion of DNRA in relation to denitrification was lower (0–16 % of total nitrate reduction). Median value and range of benthic DNRA rates from the GOB were comparable to those from the southern and central eutrophic Baltic Sea and other temperate estuaries and coasts in Europe. Therefore, our results contrast with the view that DNRA is negligible in cold and well-oxygenated sediments with low organic carbon ... |
format |
Article in Journal/Newspaper |
author |
S. Bonaglia A. Hylén J. E. Rattray M. Y. Kononets N. Ekeroth P. Roos B. Thamdrup V. Brüchert P. O. J. Hall |
author_facet |
S. Bonaglia A. Hylén J. E. Rattray M. Y. Kononets N. Ekeroth P. Roos B. Thamdrup V. Brüchert P. O. J. Hall |
author_sort |
S. Bonaglia |
title |
The fate of fixed nitrogen in marine sediments with low organic loading: an in situ study |
title_short |
The fate of fixed nitrogen in marine sediments with low organic loading: an in situ study |
title_full |
The fate of fixed nitrogen in marine sediments with low organic loading: an in situ study |
title_fullStr |
The fate of fixed nitrogen in marine sediments with low organic loading: an in situ study |
title_full_unstemmed |
The fate of fixed nitrogen in marine sediments with low organic loading: an in situ study |
title_sort |
fate of fixed nitrogen in marine sediments with low organic loading: an in situ study |
publisher |
Copernicus Publications |
publishDate |
2017 |
url |
https://doi.org/10.5194/bg-14-285-2017 https://doaj.org/article/b941dca53fbf499885cb80c962dc27c7 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Subarctic |
genre_facet |
Arctic Subarctic |
op_source |
Biogeosciences, Vol 14, Iss 2, Pp 285-300 (2017) |
op_relation |
http://www.biogeosciences.net/14/285/2017/bg-14-285-2017.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-14-285-2017 https://doaj.org/article/b941dca53fbf499885cb80c962dc27c7 |
op_doi |
https://doi.org/10.5194/bg-14-285-2017 |
container_title |
Biogeosciences |
container_volume |
14 |
container_issue |
2 |
container_start_page |
285 |
op_container_end_page |
300 |
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1766347731395149824 |