Seawater carbonate chemistry, growth rate and PIC and POC production during experiments with Emiliania huxleyi (B92/11), 2011


The coccolithophore Emiliania huxleyi was cultured under a broad range of carbonate chemistry conditions to distinguish the effects of individual carbonate system parameters on growth, primary production, and calcification. In the first experiment, alkalinity was kept constant and the fugacity of CO2(fCO2) varied from 2 to 600 Pa (1Pa ~ 10 µatm). In the second experiment, pH was kept constant (pHfree = 8) with fCO2 varying from 4 to 370 Pa. Results of the constant-alkalinity approach revealed physiological optima for growth, calcification, and organic carbon production at fCO2 values of ~20Pa, ~40 Pa, and ~80 Pa, respectively. Comparing this with the constant-pH approach showed that growth and organic carbon production increased similarly from low to intermediate CO2 levels but started to diverge towards higher CO2 levels. In the high CO2 range, growth rates and organic carbon production decreased steadily with declining pH at constant alkalinity while remaining consistently higher at constant pH. This suggests that growth and organic carbon production rates are directly related to CO2 at low (sub-saturating) concentrations, whereas towards higher CO2 levels they are adversely affected by the associated decrease in pH. A pH dependence at high fCO2 is also indicated for calcification rates, while the key carbonate system parameter determining calcification at low fCO2 remains unclear. These results imply that key metabolic processes in coccolithophores have their optima at different carbonate chemistry conditions and are influenced by different parameters of the carbonate system at both sides of the optimum.

In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Lavigne and Gattuso, 2011) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). In this dataset the original values were archived in addition with the recalculated parameters (see related PI).

Supplement to: Bach, Lennart Thomas; Riebesell, Ulf; Schulz, Kai Georg (2011): Distinguishing between the effects of ocean acidification and ocean carbonation in the coccolithophore Emiliania huxleyi. Limnology and Oceanography, 56(6), 2040-2050

Related Identifier IsSupplementTo
Metadata Access
Creator Bach, Lennart Thomas ORCID logo; Riebesell, Ulf (ORCID: 0000-0002-9442-452X); Schulz, Kai Georg ORCID logo
Publisher PANGAEA
Contributor Nisumaa, Anne-Marin
Publication Year 2011
Funding Reference Seventh Framework Programme Crossref Funder ID 211384 European Project on Ocean Acidification; Sixth Framework Programme Crossref Funder ID 511106 European network of excellence for Ocean Ecosystems Analysis
Rights Creative Commons Attribution 3.0 Unported;
OpenAccess true
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 1396 data points
Discipline Earth System Research