Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 15, issue 12 | Copyright
Biogeosciences, 15, 3691-3701, 2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Research article 19 Jun 2018

Research article | 19 Jun 2018

Population-specific responses in physiological rates of Emiliania huxleyi to a broad CO2 range

Yong Zhang1,5, Lennart T. Bach1, Kai T. Lohbeck1,2,6, Kai G. Schulz3, Luisa Listmann2, Regina Klapper4, and Ulf Riebesell1 Yong Zhang et al.
  • 1Biological Oceanography, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
  • 2Evolutionary Ecology of Marine Fishes, GEOMAR Helmholtz-Centre for Ocean Research Kiel, Kiel, Germany
  • 3Centre for Coastal Biogeochemistry, School of Science, Environment and Engineering, Southern Cross University, Lismore, NSW, Australia
  • 4Goethe University, Institute for Ecology, Evolution and Diversity; Senckenberg Gesellschaft für Naturforschung, Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
  • 5State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University (Xiang-An Campus), Xiamen 361102, China
  • 6Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden

Abstract. Although coccolithophore physiological responses to CO2-induced changes in seawater carbonate chemistry have been widely studied in the past, there is limited knowledge on the variability of physiological responses between populations from different areas. In the present study, we investigated the specific responses of growth, particulate organic (POC) and inorganic carbon (PIC) production rates of three populations of the coccolithophore Emiliania huxleyi from three regions in the North Atlantic Ocean (Azores: six strains, Canary Islands: five strains, and Norwegian coast near Bergen: six strains) to a CO2 partial pressure (pCO2) range from 120 to 2630µatm. Physiological rates of each population and individual strain increased with rising pCO2 levels, reached a maximum and declined thereafter. Optimal pCO2 for growth, POC production rates, and tolerance to low pH (i.e., high proton concentration) was significantly higher in an E. huxleyi population isolated from the Norwegian coast than in those isolated near the Azores and Canary Islands. This may be due to the large environmental variability including large pCO2 and pH fluctuations in coastal waters off Bergen compared to the rather stable oceanic conditions at the other two sites. Maximum growth and POC production rates of the Azores and Bergen populations were similar and significantly higher than that of the Canary Islands population. This pattern could be driven by temperature–CO2 interactions where the chosen incubation temperature (16°C) was slightly below what strains isolated near the Canary Islands normally experience. Our results indicate adaptation of E. huxleyi to their local environmental conditions and the existence of distinct E. huxleyi populations. Within each population, different growth, POC, and PIC production rates at different pCO2 levels indicated strain-specific phenotypic plasticity. Accounting for this variability is important to understand how or whether E. huxleyi might adapt to rising CO2 levels.

Download & links
Publications Copernicus
Short summary
To compare variations in physiological responses to pCO2 between populations, we measured growth, POC and PIC production rates at a pCO2 range from 120 to 2630 µatm for 17 strains of the coccolithophore Emiliania huxleyi from the Azores, Canary Islands, and Norwegian coast near Bergen. Optimal pCO2 for growth and POC production rates and tolerance to low pH was significantly higher for the Bergen population than the Azores and Canary Islands populations.
To compare variations in physiological responses to pCO2 between populations, we measured...