High plasticity in inorganic carbon uptake by Southern Ocean phytoplankton in response to ambient CO 2

The fixation of dissolved inorganic carbon (DIC) by marine phytoplankton provides an important feedback mechanism on concentrations of CO2 in the atmosphere. As a consequence it is important to determine whether oceanic primary productivity is susceptible to changing atmospheric CO2 levels. Among nu...

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Bibliographic Details
Published in:Deep Sea Research Part II: Topical Studies in Oceanography
Main Authors: Neven, Ika A., Stefels, Jacqueline, van Heuven, Steven M. A. C., de Baar, Hein J. W., Elzenga, J. Theo M.
Format: Article in Journal/Newspaper
Language:English
Published: 2011
Subjects:
Carbon sink
CO2 concentrating mechanism
HCO3-
Carbonic anhydrase
Isotope disequilibrium technique
Weddell Sea
ISOTOPIC DISEQUILIBRIUM TECHNIQUE
MARINE-PHYTOPLANKTON
IRON LIMITATION
CO2-CONCENTRATING MECHANISMS
CONCENTRATING MECHANISMS
ENRICHMENT EXPERIMENTS
BICARBONATE TRANSPORT
LIGHT AVAILABILITY
ANHYDRASE ACTIVITY
GROWTH-RATES
Southern Ocean
Weddell
Online Access:https://hdl.handle.net/11370/74b3cc87-baaf-449e-92cc-34e4915bb8d0
https://research.rug.nl/en/publications/74b3cc87-baaf-449e-92cc-34e4915bb8d0
https://doi.org/10.1016/j.dsr2.2011.03.006
https://pure.rug.nl/ws/files/6770267/2011DeepSeaRes2Neven.pdf
Description
Summary:The fixation of dissolved inorganic carbon (DIC) by marine phytoplankton provides an important feedback mechanism on concentrations of CO2 in the atmosphere. As a consequence it is important to determine whether oceanic primary productivity is susceptible to changing atmospheric CO2 levels. Among numerous other factors, the acquisition of DIC by microalgae particularly in the polar seas is projected to have a significant effect on future phytoplanktonic production and hence atmospheric CO2 concentrations. Using the isotopic disequilibrium technique the contribution of different carbon species (CO2 and bicarbonate) to the overall DIC uptake and the extent to which external Carbonic Anhydrase (eCA) plays a role in facilitating DIC uptake was estimated. Simultaneous uptake of CO2 and HCO3- was observed in all cases, but the proportions in which different DIC species contributed to carbon assimilation varied considerably between stations. Bicarbonate as well as CO2 could be the major DIC source for local phytoplankton assemblages. There was a positive correlation between the contribution of CO2 to total DIC uptake and ambient concentration of CO2 in seawater suggesting that Southern Ocean microalgae could increase the proportion of CO2 uptake under future high atmospheric CO2 levels. Results will be discussed in view of metabolic costs related to DIC acquisition of Southern Ocean phytoplankton. (C) 2011 Elsevier Ltd. All rights reserved.

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