Photoproduction of Ammonium in the Southeastern Beaufort Sea and Its Biogeochemical Implications
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 ammoni...
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ftunivsouthcar:oai:scholarcommons.sc.edu:geol_facpub-1191 2024-05-19T07:38:13+00:00 Photoproduction of Ammonium in the Southeastern Beaufort Sea and Its Biogeochemical Implications Xie, H. Belanger, S. Song, G. Benner, Ronald Taalba, A. Blais, M. Tremblay, J. É Babin, M. 2012-01-01T08:00:00Z application/pdf https://scholarcommons.sc.edu/geol_facpub/163 https://doi.org/10.5194/bg-9-3047-2012; https://scholarcommons.sc.edu/context/geol_facpub/article/1191/viewcontent/bg_9_3047_2012.pdf English eng Scholar Commons https://scholarcommons.sc.edu/geol_facpub/163 doi: https://doi.org/10.5194/bg-9-3047-2012 https://scholarcommons.sc.edu/context/geol_facpub/article/1191/viewcontent/bg_9_3047_2012.pdf © Author(s) 2012. This work is distributed under the Creative Commons Attribution 3.0 License . Faculty Publications photoproduction ammonium Beaufort Sea Sea biogeochemical implications Biology Oceanography and Atmospheric Sciences and Meteorology text 2012 ftunivsouthcar https://doi.org/10.5194/bg-9-3047-2012;10.5194/bg-9-3047-2012 2024-04-30T23:59:54Z 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 (NH4+).During the August 2009 Mackenzie Light and Carbon (MALINA) Program, the absorbed photon-based efficiency spectra of NH4+ 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 CO2 and CO photoproduction, this study revealed a stoichiometry of DOM photochemistry with a CO2 : CO :NH4+ molar ratio of 165 : 11 : 1 in the estuary, 60 : 3 : 1 on the shelf, and 18 : 2 : 1 in the Canada Basin. The NH4+ 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 NH4+ photoproduction in the entire study area was estimated to be 1.4 × 108 moles, with 85% of it being generated in summer when ... Text Beaufort Sea canada basin Mackenzie river Mackenzie Shelf Sea ice University of South Carolina Libraries: Scholar Commons |
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University of South Carolina Libraries: Scholar Commons |
op_collection_id |
ftunivsouthcar |
language |
English |
topic |
photoproduction ammonium Beaufort Sea Sea biogeochemical implications Biology Oceanography and Atmospheric Sciences and Meteorology |
spellingShingle |
photoproduction ammonium Beaufort Sea Sea biogeochemical implications Biology Oceanography and Atmospheric Sciences and Meteorology Xie, H. Belanger, S. Song, G. Benner, Ronald Taalba, A. Blais, M. Tremblay, J. É Babin, M. Photoproduction of Ammonium in the Southeastern Beaufort Sea and Its Biogeochemical Implications |
topic_facet |
photoproduction ammonium Beaufort Sea Sea biogeochemical implications Biology Oceanography and Atmospheric Sciences and Meteorology |
description |
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 (NH4+).During the August 2009 Mackenzie Light and Carbon (MALINA) Program, the absorbed photon-based efficiency spectra of NH4+ 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 CO2 and CO photoproduction, this study revealed a stoichiometry of DOM photochemistry with a CO2 : CO :NH4+ molar ratio of 165 : 11 : 1 in the estuary, 60 : 3 : 1 on the shelf, and 18 : 2 : 1 in the Canada Basin. The NH4+ 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 NH4+ photoproduction in the entire study area was estimated to be 1.4 × 108 moles, with 85% of it being generated in summer when ... |
format |
Text |
author |
Xie, H. Belanger, S. Song, G. Benner, Ronald Taalba, A. Blais, M. Tremblay, J. É Babin, M. |
author_facet |
Xie, H. Belanger, S. Song, G. Benner, Ronald 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 |
Scholar Commons |
publishDate |
2012 |
url |
https://scholarcommons.sc.edu/geol_facpub/163 https://doi.org/10.5194/bg-9-3047-2012; https://scholarcommons.sc.edu/context/geol_facpub/article/1191/viewcontent/bg_9_3047_2012.pdf |
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 |
Faculty Publications |
op_relation |
https://scholarcommons.sc.edu/geol_facpub/163 doi: https://doi.org/10.5194/bg-9-3047-2012 https://scholarcommons.sc.edu/context/geol_facpub/article/1191/viewcontent/bg_9_3047_2012.pdf |
op_rights |
© Author(s) 2012. This work is distributed under the Creative Commons Attribution 3.0 License . |
op_doi |
https://doi.org/10.5194/bg-9-3047-2012;10.5194/bg-9-3047-2012 |
_version_ |
1799477623639769088 |