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Primary productivity, new productivity, and their relation to carbon flux during two Southern Ocean Gas Exchange tracer experiments

Citation

Lance, VP and Strutton, PG and Vaillancourt, RD and Hargreaves, BR and Zhang, J-Z and Marra, J, Primary productivity, new productivity, and their relation to carbon flux during two Southern Ocean Gas Exchange tracer experiments, Journal of Geophysical Research: Oceans, 117, (4) Article C00F14. ISSN 0148-0227 (2012) [Refereed Article]


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Copyright Statement

Copyright 2012 American Geophysical Union.

DOI: doi:10.1029/2011JC007687

Abstract

[1] Biological uptake rates of inorganic carbon and nitrate were measured during two sequential tracer release gas exchange experiments, together known as the Southern Ocean Gas Exchange Experiment (SO GasEx) in the southwest Atlantic sector of the Southern Ocean Antarctic Zone (51°N, 38°W). Primary productivity estimated from 14C incubations ranged from 26.7 to 47.2 mmol C m−2 d−1 in the first experiment (Patch 1) and 13.7 to 39.4 mmol C m−2 d−1 in the second experiment (Patch 2). Nitrate-based productivity estimated from 15NO3 incubations ranged from 5.8 to 13.1 mmol C m−2 d−1 in Patch 1 and 1.9 to 7.1 mmol C m−2 d−1 in Patch 2. The average ratio of nitrate-based productivity to primary productivity (approximating the f ratio) was 0.24 in Patch 1 and 0.15 in Patch 2. Chlorophyll concentrations for both patches were less than 1 mg m−3. Photochemical efficiency (Fv/Fm) was low (∼0.3) in Patch 1 and moderate (∼0.45) in Patch 2. Si(OH)4 concentrations were potentially limiting (<1 mmol m−3 for Patch 1 and ∼3 mmol m−3 for Patch 2), while NH4+ concentrations were elevated (∼1 mmol m−3 for Patch 1 and ∼2.2 mmol m−3 for Patch 2) compared with typical open ocean Antarctic Zone water. We hypothesize that Patch 1 productivity was regulated by the availability of Si(OH)4, while Patch 2 productivity was regulated by grazers. Primary production and nitrate-based production (as a proxy for C export) determined here provide components for a mixed layer carbon budget from which the air-sea flux of CO2 will be quantified.

Item Details

Item Type:Refereed Article
Keywords:southern ocean, primary productivity
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Biological Oceanography
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:Strutton, PG (Associate Professor Peter Strutton)
ID Code:80216
Year Published:2012
Web of Science® Times Cited:2
Deposited By:IMAS Research and Education Centre
Deposited On:2012-10-24
Last Modified:2017-08-25
Downloads:0

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