TY - DATA ID - langer2006sccg T1 - Seawater carbonate chemistry, growth rate and processes during experiments with Coccolithus pelagicus and Calcidiscus leptoporus, 2006 AU - Langer, Gerald AU - Geisen, Markus AU - Baumann, Karl-Heinz AU - Kläs, Jessica AU - Riebesell, Ulf AU - Thoms, Silke AU - Young, Jeremy PY - 2006 T2 - Supplement to: Langer, G et al. (2006): Species-specific responses of calcifying algae to changing seawater carbonate chemistry. Geochemistry, Geophysics, Geosystems, 7, Q09006, https://doi.org/10.1029/2005GC001227 PB - PANGAEA DO - 10.1594/PANGAEA.721107 UR - https://doi.org/10.1594/PANGAEA.721107 N2 - Uptake of half of the fossil fuel CO2 into the ocean causes gradual seawater acidification. This has been shown to slow down calcification of major calcifying groups, such as corals, foraminifera, and coccolithophores. Here we show that two of the most productive marine calcifying species, the coccolithophores Coccolithus pelagicus and Calcidiscus leptoporus, do not follow the CO2-related calcification response previously found. In batch culture experiments, particulate inorganic carbon (PIC) of C. leptoporus changes with increasing CO2 concentration in a nonlinear relationship. A PIC optimum curve is obtained, with a maximum value at present-day surface ocean pCO2 levels (?360 ppm CO2). With particulate organic carbon (POC) remaining constant over the range of CO2 concentrations, the PIC/POC ratio also shows an optimum curve. In the C. pelagicus cultures, neither PIC nor POC changes significantly over the CO2 range tested, yielding a stable PIC/POC ratio. Since growth rate in both species did not change with pCO2, POC and PIC production show the same pattern as POC and PIC. The two investigated species respond differently to changes in the seawater carbonate chemistry, highlighting the need to consider species-specific effects when evaluating whole ecosystem responses. Changes of calcification rate (PIC production) were highly correlated to changes in coccolith morphology. Since our experimental results suggest altered coccolith morphology (at least in the case of C. leptoporus) in the geological past, coccoliths originating from sedimentary records of periods with different CO2 levels were analyzed. Analysis of sediment samples was performed on six cores obtained from locations well above the lysocline and covering a range of latitudes throughout the Atlantic Ocean. Scanning electron micrograph analysis of coccolith morphologies did not reveal any evidence for significant numbers of incomplete or malformed coccoliths of C. pelagicus and C. leptoporus in last glacial maximum and Holocene sediments. The discrepancy between experimental and geological results might be explained by adaptation to changing carbonate chemistry. KW - Bottles or small containers/Aquaria (<20 L) KW - Calcidiscus leptoporus KW - Calcification/Dissolution KW - Chromista KW - Coccolithus pelagicus KW - Growth/Morphology KW - Haptophyta KW - Laboratory experiment KW - Laboratory strains KW - Pelagos KW - Phytoplankton KW - Primary production/Photosynthesis KW - Single species KW - South Atlantic ER -