Photoproduction of ammonium in the southeastern Beaufort Sea and its biogeochemical implications
International audience Photochemistry of dissolved organic matter (DOM) plays an important role in marine biogeochemical cycles, including the regeneration of inorganic nutrients. DOM photochemistry affects nitrogen cycling by converting bio-refractory dissolved organic nitrogen to labile inorganic...
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Online Access: | https://hal.science/hal-04110601 https://hal.science/hal-04110601/document https://hal.science/hal-04110601/file/bg-9-3047-2012.pdf https://doi.org/10.5194/bg-9-3047-2012 |
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ftinsu:oai:HAL:hal-04110601v1 2023-11-05T03:40:50+01:00 Photoproduction of ammonium in the southeastern Beaufort Sea and its biogeochemical implications Xie, H. Bélanger, S. Song, G. Benner, R. Taalba, A. Blais, M. Tremblay, J. -É. Babin, M. Laboratoire d'océanographie de Villefranche (LOV) Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV) Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) 2012 https://hal.science/hal-04110601 https://hal.science/hal-04110601/document https://hal.science/hal-04110601/file/bg-9-3047-2012.pdf https://doi.org/10.5194/bg-9-3047-2012 en eng HAL CCSD info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-9-3047-2012 hal-04110601 https://hal.science/hal-04110601 https://hal.science/hal-04110601/document https://hal.science/hal-04110601/file/bg-9-3047-2012.pdf BIBCODE: 2012BGeo.9.3047X doi:10.5194/bg-9-3047-2012 http://creativecommons.org/licenses/by/ info:eu-repo/semantics/OpenAccess Biogeosciences https://hal.science/hal-04110601 Biogeosciences, 2012, 9, pp.3047-3061. ⟨10.5194/bg-9-3047-2012⟩ Earth Science [SDU]Sciences of the Universe [physics] info:eu-repo/semantics/article Journal articles 2012 ftinsu https://doi.org/10.5194/bg-9-3047-2012 2023-10-11T16:24:07Z International audience Photochemistry of dissolved organic matter (DOM) plays an important role in marine biogeochemical cycles, including the regeneration of inorganic nutrients. DOM photochemistry affects nitrogen cycling by converting bio-refractory dissolved organic nitrogen to labile inorganic nitrogen, mainly ammonium (NH 4 + ). During the August 2009 Mackenzie Light and Carbon (MALINA) Program, the absorbed photon-based efficiency spectra of NH 4 + photoproduction (i.e. photoammonification) were determined using water samples from the SE Beaufort Sea, including the Mackenzie River estuary, shelf, and Canada Basin. The photoammonification efficiency decreased with increasing wavelength across the ultraviolet and visible regimes and was higher in offshore waters than in shelf and estuarine waters. The efficiency was positively correlated with the molar nitrogen:carbon ratio of DOM and negatively correlated with the absorption coefficient of chromophoric DOM (CDOM). Combined with collateral measurements of CO 2 and CO photoproduction, this study revealed a stoichiometry of DOM photochemistry with a CO 2 : CO : NH 4 + molar ratio of 165 : 11 : 1 in the estuary, 60 : 3 : 1 on the shelf, and 18 : 2 : 1 in the Canada Basin. The NH 4 + efficiency spectra, along with solar photon fluxes, CDOM absorption coefficients and sea ice concentrations, were used to model the monthly surface and depth-integrated photoammonification rates in 2009. The summertime (June-August) rates at the surface reached 6.6 nmol l -1 d -1 on the Mackenzie Shelf and 3.7 nmol l -1 d -1 further offshore; the depth-integrated rates were correspondingly 8.8 μmol m -2 d -1 and 11.3 μmol m -2 d -1 . The offshore depth-integrated rate in August (8.0 μmol m -2 d -1 ) was comparable to the missing dissolved inorganic nitrogen (DIN) source required to support the observed primary production in the upper 10-m layer of that area. The yearly NH 4 + photoproduction in the entire study area was estimated to be 1.4 × 10 8 moles, with 85% of it being ... Article in Journal/Newspaper Beaufort Sea canada basin Mackenzie river Mackenzie Shelf Sea ice Institut national des sciences de l'Univers: HAL-INSU Biogeosciences 9 8 3047 3061 |
institution |
Open Polar |
collection |
Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
English |
topic |
Earth Science [SDU]Sciences of the Universe [physics] |
spellingShingle |
Earth Science [SDU]Sciences of the Universe [physics] Xie, H. Bélanger, S. Song, G. Benner, R. Taalba, A. Blais, M. Tremblay, J. -É. Babin, M. Photoproduction of ammonium in the southeastern Beaufort Sea and its biogeochemical implications |
topic_facet |
Earth Science [SDU]Sciences of the Universe [physics] |
description |
International audience Photochemistry of dissolved organic matter (DOM) plays an important role in marine biogeochemical cycles, including the regeneration of inorganic nutrients. DOM photochemistry affects nitrogen cycling by converting bio-refractory dissolved organic nitrogen to labile inorganic nitrogen, mainly ammonium (NH 4 + ). During the August 2009 Mackenzie Light and Carbon (MALINA) Program, the absorbed photon-based efficiency spectra of NH 4 + photoproduction (i.e. photoammonification) were determined using water samples from the SE Beaufort Sea, including the Mackenzie River estuary, shelf, and Canada Basin. The photoammonification efficiency decreased with increasing wavelength across the ultraviolet and visible regimes and was higher in offshore waters than in shelf and estuarine waters. The efficiency was positively correlated with the molar nitrogen:carbon ratio of DOM and negatively correlated with the absorption coefficient of chromophoric DOM (CDOM). Combined with collateral measurements of CO 2 and CO photoproduction, this study revealed a stoichiometry of DOM photochemistry with a CO 2 : CO : NH 4 + molar ratio of 165 : 11 : 1 in the estuary, 60 : 3 : 1 on the shelf, and 18 : 2 : 1 in the Canada Basin. The NH 4 + efficiency spectra, along with solar photon fluxes, CDOM absorption coefficients and sea ice concentrations, were used to model the monthly surface and depth-integrated photoammonification rates in 2009. The summertime (June-August) rates at the surface reached 6.6 nmol l -1 d -1 on the Mackenzie Shelf and 3.7 nmol l -1 d -1 further offshore; the depth-integrated rates were correspondingly 8.8 μmol m -2 d -1 and 11.3 μmol m -2 d -1 . The offshore depth-integrated rate in August (8.0 μmol m -2 d -1 ) was comparable to the missing dissolved inorganic nitrogen (DIN) source required to support the observed primary production in the upper 10-m layer of that area. The yearly NH 4 + photoproduction in the entire study area was estimated to be 1.4 × 10 8 moles, with 85% of it being ... |
author2 |
Laboratoire d'océanographie de Villefranche (LOV) Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV) Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Xie, H. Bélanger, S. Song, G. Benner, R. Taalba, A. Blais, M. Tremblay, J. -É. Babin, M. |
author_facet |
Xie, H. Bélanger, S. Song, G. Benner, R. Taalba, A. Blais, M. Tremblay, J. -É. Babin, M. |
author_sort |
Xie, H. |
title |
Photoproduction of ammonium in the southeastern Beaufort Sea and its biogeochemical implications |
title_short |
Photoproduction of ammonium in the southeastern Beaufort Sea and its biogeochemical implications |
title_full |
Photoproduction of ammonium in the southeastern Beaufort Sea and its biogeochemical implications |
title_fullStr |
Photoproduction of ammonium in the southeastern Beaufort Sea and its biogeochemical implications |
title_full_unstemmed |
Photoproduction of ammonium in the southeastern Beaufort Sea and its biogeochemical implications |
title_sort |
photoproduction of ammonium in the southeastern beaufort sea and its biogeochemical implications |
publisher |
HAL CCSD |
publishDate |
2012 |
url |
https://hal.science/hal-04110601 https://hal.science/hal-04110601/document https://hal.science/hal-04110601/file/bg-9-3047-2012.pdf https://doi.org/10.5194/bg-9-3047-2012 |
genre |
Beaufort Sea canada basin Mackenzie river Mackenzie Shelf Sea ice |
genre_facet |
Beaufort Sea canada basin Mackenzie river Mackenzie Shelf Sea ice |
op_source |
Biogeosciences https://hal.science/hal-04110601 Biogeosciences, 2012, 9, pp.3047-3061. ⟨10.5194/bg-9-3047-2012⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-9-3047-2012 hal-04110601 https://hal.science/hal-04110601 https://hal.science/hal-04110601/document https://hal.science/hal-04110601/file/bg-9-3047-2012.pdf BIBCODE: 2012BGeo.9.3047X doi:10.5194/bg-9-3047-2012 |
op_rights |
http://creativecommons.org/licenses/by/ info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.5194/bg-9-3047-2012 |
container_title |
Biogeosciences |
container_volume |
9 |
container_issue |
8 |
container_start_page |
3047 |
op_container_end_page |
3061 |
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1781697054100160512 |