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Article: Benthic nutrient fluxes along the Laurentian Channel: Impacts on the N budget of the St. Lawrence marine system

TitleBenthic nutrient fluxes along the Laurentian Channel: Impacts on the N budget of the St. Lawrence marine system
Authors
KeywordsNitrogen cycle
Denitrification
Estuary
Geochemistry
St. Lawrence
Issue Date2010
Citation
Estuarine, Coastal and Shelf Science, 2010, v. 90, n. 4, p. 195-205 How to Cite?
AbstractWater column concentrations and benthic fluxes of dissolved inorganic nitrogen (DIN) and oxygen (DO) were measured in the Gulf of St. Lawrence and the Upper and Lower St. Lawrence Estuary (USLE and LSLE, respectively) to assess the nitrogen (N) budget in the St. Lawrence (SL) system, as well as to elucidate the impact of bottom water hypoxia on fixed-N removal in the LSLE. A severe nitrate deficit, with respect to ambient phosphate concentrations (Ñ∼-10 μmol L-1), was observed within and in the vicinity of the hypoxic bottom water of the LSLE. Given that DO concentrations in the water column have remained above 50 μmol L-1, nitrate reduction in suboxic sediments, rather than in the water column, is most likely responsible for the removal of fixed N from the SL system. Net nitrate fluxes into the sediments, derived from pore water nitrate concentration gradients, ranged from 190 μmol m-2 d-1 in the hypoxic western LSLE to 100 μmol m-2 d-1 in the Gulf. The average total benthic nitrate reduction rate for the Laurentian Channel (LC) is on the order of 690 μmol m-2 d-1, with coupled nitrification-nitrate reduction accounting for more than 70%. Using average nitrate reduction rates derived from the observed water column nitrate deficit, the annual fixed-N elimination within the three main channels of the Gulf of St. Lawrence and LSLE was estimated at 411 × 106 t N, yielding an almost balanced N budget for the SL marine system. © 2010 Elsevier Ltd.
Persistent Identifierhttp://hdl.handle.net/10722/210591
ISSN
2015 Impact Factor: 2.335
2015 SCImago Journal Rankings: 1.094

 

DC FieldValueLanguage
dc.contributor.authorThibodeau, Benoît-
dc.contributor.authorLehmann, Moritz F.-
dc.contributor.authorKowarzyk, Jacqueline-
dc.contributor.authorMucci, Alfonso-
dc.contributor.authorGélinas, Yves-
dc.contributor.authorGilbert, Denis-
dc.contributor.authorMaranger, Roxane-
dc.contributor.authorAlkhatib, Mohammad-
dc.date.accessioned2015-06-19T01:49:29Z-
dc.date.available2015-06-19T01:49:29Z-
dc.date.issued2010-
dc.identifier.citationEstuarine, Coastal and Shelf Science, 2010, v. 90, n. 4, p. 195-205-
dc.identifier.issn0272-7714-
dc.identifier.urihttp://hdl.handle.net/10722/210591-
dc.description.abstractWater column concentrations and benthic fluxes of dissolved inorganic nitrogen (DIN) and oxygen (DO) were measured in the Gulf of St. Lawrence and the Upper and Lower St. Lawrence Estuary (USLE and LSLE, respectively) to assess the nitrogen (N) budget in the St. Lawrence (SL) system, as well as to elucidate the impact of bottom water hypoxia on fixed-N removal in the LSLE. A severe nitrate deficit, with respect to ambient phosphate concentrations (Ñ∼-10 μmol L-1), was observed within and in the vicinity of the hypoxic bottom water of the LSLE. Given that DO concentrations in the water column have remained above 50 μmol L-1, nitrate reduction in suboxic sediments, rather than in the water column, is most likely responsible for the removal of fixed N from the SL system. Net nitrate fluxes into the sediments, derived from pore water nitrate concentration gradients, ranged from 190 μmol m-2 d-1 in the hypoxic western LSLE to 100 μmol m-2 d-1 in the Gulf. The average total benthic nitrate reduction rate for the Laurentian Channel (LC) is on the order of 690 μmol m-2 d-1, with coupled nitrification-nitrate reduction accounting for more than 70%. Using average nitrate reduction rates derived from the observed water column nitrate deficit, the annual fixed-N elimination within the three main channels of the Gulf of St. Lawrence and LSLE was estimated at 411 × 106 t N, yielding an almost balanced N budget for the SL marine system. © 2010 Elsevier Ltd.-
dc.languageeng-
dc.relation.ispartofEstuarine, Coastal and Shelf Science-
dc.subjectNitrogen cycle-
dc.subjectDenitrification-
dc.subjectEstuary-
dc.subjectGeochemistry-
dc.subjectSt. Lawrence-
dc.titleBenthic nutrient fluxes along the Laurentian Channel: Impacts on the N budget of the St. Lawrence marine system-
dc.typeArticle-
dc.description.natureLink_to_subscribed_fulltext-
dc.identifier.doi10.1016/j.ecss.2010.08.015-
dc.identifier.scopuseid_2-s2.0-78449244298-
dc.identifier.volume90-
dc.identifier.issue4-
dc.identifier.spage195-
dc.identifier.epage205-

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