AB 7:59-70 (2009)  -  DOI: https://doi.org/10.3354/ab00182

ABSTRACT: Production (abundance and biomass) and net calcification rates of the coccolithophorid Pleurochrysis carterae under different partial pressures of CO₂ (pCO₂) were examined using short (15, 24 and 39 h), long (7 d) and dark (7 d) incubation experiments. Short incubations were conducted at ambient, 500 and 820 ppm pCO₂ levels in natural seawater that was enriched with nutrients and inoculated with P. carterae. Long incubations were conducted at ambient and 1200 ppm pCO₂ levels in natural seawater (0.2 µm filtered as well as unfiltered) that was enriched with nutrients and inoculated with P. carterae. Dark incubations were conducted at ambient and 1200 ppm pCO₂ in unfiltered seawater that was inoculated with P. carterae. The abundance and biomass of coccolithophorids increased with pCO₂ and time. The abundance and biomass of most noncalcifying phytoplankton also increased, and were hardly affected by CO₂ inputs. Net calcification rates were negative in short incubations during the pre-bloom phase regardless of pCO₂ levels, indicating dissolution of calcium carbonate. Further, the negative values of net calcification in short incubations became less negative with time. Net calcification rates were positive in long incubations during blooms regardless of pCO₂ level, and the rate of calcification increased with pCO₂. Our results show that P. carterae may adapt to increased (~1200 ppm) pCO₂ level with time, and such increase has little effect on the ecology of noncalcifying groups and hence in ecosystem dynamics. In dark incubations, net calcification rates were negative, with the magnitude being dependent on pCO₂ levels.

KEY WORDS: pCO₂ · Pleurochrysis carterae · Noncalcifying phytoplankton · Biomass · Net calcification rates · Adaptation

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Cite this article as: Casareto BE, Niraula MP, Fujimura H, Suzuki Y (2009) Effects of carbon dioxide on the coccolithophorid Pleurochrysis carterae in incubation experiments. Aquat Biol 7:59-70. https://doi.org/10.3354/ab00182 Export citation Share:    Facebook - - linkedIn