Biogeochemical response of Emiliania huxleyi (PML B92/11) to elevated CO2 and temperature under phosphorous limitation: a chemostat study.

Borchard, Corinna, Borges, A., Händel, N. and Engel, Anja (2011) Biogeochemical response of Emiliania huxleyi (PML B92/11) to elevated CO2 and temperature under phosphorous limitation: a chemostat study. Journal of Experimental Marine Biology and Ecology, 410 . pp. 61-71. DOI 10.1016/j.jembe.2011.10.004.

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Abstract

The present study investigates the combined effect of phosphorous limitation, elevated partial pressure of CO2 (pCO2) and temperature on a calcifying strain of Emiliania huxleyi (PML B92/11) by means of a fully controlled
continuous culture facility. Two levels of phosphorous limitation were consecutively applied by renewal of culture media (N:P=26) at dilution rates (D) of 0.3 d−1 and 0.1 d−1. CO2 and temperature conditions were 300, 550 and 900 μatm pCO2 at 14 °C and 900 μatm pCO2 at 18 °C. In general, the steady state cell density and particulate organic carbon (POC) production increased with pCO2, yielding significantly higher concentrations in cultures grown at 900 μatm pCO2 compared to 300 and 550 μatm pCO2. At 900 μatm pCO2, elevation of temperature as expected for a greenhouse ocean, further increased cell densities and POC concentrations. In contrast to POC concentration, C-quotas (pmol C cell−1) were similar at D=0.3 d−1 in all cultures. At D=0.1 d−1, a reduction of C-quotas by up to 15% was observed in the 900 μatm pCO2 at 18 °C culture. As a result of growth rate reduction, POC:PON:POP ratios deviated strongly from the Redfield ratio, primarily due to an increase in POC. Ratios of particulate inorganic and organic carbon (PIC:POC) ranged from 0.14 to 0.18 at D=0.3 d−1, and from 0.11 to 0.17 at D=0.1 d−1, with variations primarily induced
by the changes in POC. At D=0.1 d−1, cell volume was reduced by up to 22% in cultures grown at 900 μatm pCO2. Our results indicate that changes in pCO2, temperature and phosphorus supply affect cell density, POC
concentration and size of E. huxleyi (PML B92/11) to varying degrees, and will likely impact bloom development as well as biogeochemical cycling in a greenhouse ocean.

Document Type: Article
Funder compliance: info:eu-repo/grantAgreement/EC/FP7/211384
Keywords: Biological Oceanography; Biogeochemistry; Carbonate system; Chemostat; CO2; Emiliania huxleyi; Stoichiometry; Temperature; DISSOLVED INORGANIC CARBON; CONCENTRATING MECHANISMS; COCCOLITH DETACHMENT; CONTINUOUS-CULTURE; MARINE PLANKTON; ORGANIC-CARBON; OCEAN; CALCIFICATION; SEAWATER; PRYMNESIOPHYCEAE
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-BI Biological Oceanography
AWI
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1016/j.jembe.2011.10.004
ISSN: 0022-0981
Projects: EPOCA, PEACE
Date Deposited: 26 Sep 2011 06:03
Last Modified: 23 Sep 2019 22:18
URI: http://oceanrep.geomar.de/id/eprint/12172

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