In:
Biogeosciences, Copernicus GmbH, Vol. 15, No. 12 ( 2018-06-19), p. 3691-3701
Abstract:
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 2630 µatm.
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.
Type of Medium:
Online Resource
ISSN:
1726-4189
DOI:
10.5194/bg-15-3691-2018
DOI:
10.5194/bg-15-3691-2018-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2018
detail.hit.zdb_id:
2158181-2
