Population-specific responses in physiological rates of Emiliania huxleyi to a broad CO2 range
Although coccolithophore physiological responses to CO2-inducedchanges in seawater carbonate chemistry have been widely studied in the past,there is limited knowledge on the variability of physiological responsesbetween populations from different areas. In the present study, weinvestigated the speci...
| Published in: | Biogeosciences |
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| Main Authors: | , , , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Copernicus GmbH
2018
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| Subjects: | |
| Online Access: | https://eprints.utas.edu.au/30886/ https://eprints.utas.edu.au/30886/1/133680%20-%20Population-specific%20responses%20in%20physiological%20rates%20of%20Emiliania%20huxleyi.pdf |
| Summary: | Although coccolithophore physiological responses to CO2-inducedchanges in seawater carbonate chemistry have been widely studied in the past,there is limited knowledge on the variability of physiological responsesbetween populations from different areas. In the present study, weinvestigated the specific responses of growth, particulate organic (POC) andinorganic carbon (PIC) production rates of three populations of thecoccolithophore Emiliania huxleyi from three regions in the NorthAtlantic Ocean (Azores: six strains, Canary Islands: five strains, and Norwegiancoast 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 withrising pCO2 levels, reached a maximum and declined thereafter.Optimal pCO2 for growth, POC production rates, and tolerance tolow pH (i.e., high proton concentration) was significantly higher in anE. huxleyi population isolated from the Norwegian coast than in thoseisolated near the Azores and Canary Islands. This may be due to the largeenvironmental variability including large pCO2 and pHfluctuations in coastal waters off Bergen compared to the rather stableoceanic conditions at the other two sites. Maximum growth and POC productionrates of the Azores and Bergen populations were similar and significantlyhigher than that of the Canary Islands population. This pattern could bedriven by temperature–CO2 interactions where the chosen incubationtemperature (16 ∘C) was slightly below what strains isolated near theCanary Islands normally experience. Our results indicate adaptation ofE. huxleyi to their local environmental conditions and the existenceof distinct E. huxleyi populations. Within each population,different growth, POC, and PIC production rates at different pCO2levels indicated strain-specific phenotypic plasticity. Accounting for thisvariability is important to understand how or whether E. huxleyimight adapt to rising CO2 levels. |
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