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Inorganic carbon uptake by Southern Ocean phytoplankton


Tortell, PD and Payne, C and Gueguen, C and Strzepek, RF and Boyd, PW and Rost, B, Inorganic carbon uptake by Southern Ocean phytoplankton, Limnology and Oceanography, 53, (4) pp. 1266-1278. ISSN 0024-3590 (2008) [Refereed Article]


Copyright Statement

Copyright 2008 The American Society of Limnology and Oceanography Inc.

DOI: doi:10.4319/lo.2008.53.4.1266


We report the results of laboratory and field studies examining inorganic carbon (Ci) utilization by Southern Ocean phytoplankton. Both in monospecific laboratory cultures of diatoms and Phaeocystis antarctica and in natural assemblages in the Ross Sea, Ci uptake by phytoplankton was dominated by direct HCO31 transport. The contribution of HCO31 transport to total Ci uptake ranged from 65% to 95%, with an overall average of ~80%. There was no significant difference among diatoms and Phaeocystis in the extent of HCO31 transport. Extracellular carbonic anhydrase activity (eCA) was detected in eight of nine laboratory phytoplankton cultures and in all natural assemblages in the Ross Sea. The effective catalytic enhancement of HCO31 : CO2 interconversion ranged from 1.5- to 13-fold (overall mean ~4-fold). Diatom-dominated Ross Sea assemblages had significantly greater eCA levels than did Phaeocystis-dominated assemblages. We found no strong correlations between Ci uptake parameters and in situ CO2 concentrations or chlorophyll a levels in the Ross Sea assemblages. Incubation experiments with natural assemblages showed that HCO31 uptake and eCA expression did not change significantly over an 8-fold range in pCO2 (10.1-81.1 Pa), although total short-term C fixation rates increased under low CO2 conditions. Carbon-concentrating mechanisms are widespread among Southern Ocean phytoplankton and constitutively expressed by natural assemblages in the Ross Sea.

Item Details

Item Type:Refereed Article
Research Division:Environmental Sciences
Research Group:Climate change impacts and adaptation
Research Field:Ecological impacts of climate change and ecological adaptation
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Adaptation to climate change
Objective Field:Ecosystem adaptation to climate change
UTAS Author:Strzepek, RF (Dr Robert Strzepek)
UTAS Author:Boyd, PW (Professor Philip Boyd)
ID Code:95533
Year Published:2008
Web of Science® Times Cited:59
Deposited By:IMAS Research and Education Centre
Deposited On:2014-10-03
Last Modified:2021-11-17
Downloads:652 View Download Statistics

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