Seawater carbonate chemistry and particulate inorganic carbon, particulate organic carbon production, and growth rates of Scyphosphaera apsteinii

• Main Authors: Gafar, Natasha A, Eyre, Bradley D, Schulz, Kai Georg
• Format: Dataset
• Language: English
• Published: PANGAEA 2019
• Subjects: Alkalinity; total; Aragonite saturation state; Bicarbonate ion; Bottles or small containers/Aquaria (<20 L); Calcification/Dissolution; Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; particulate; per cell; organic; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Cell biovolume; standard deviation; Chromista; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Growth rate; Haptophyta; Hydrogen ion concentration; Irradiance; Laboratory experiment; Laboratory strains; Length; Light; Not applicable; Number; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Particulate inorganic carbon/particulate organic carbon ratio; Particulate organic carbon production per cell; pH; Phytoplankton; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.919773; https://doi.org/10.1594/PANGAEA.919773

Coccolithophores are unicellular marine phytoplankton and important contributors to global carbon cycling. Most work on coccolithophore sensitivity to climate change has been on the small, abundant bloom-forming species Emiliania huxleyi and Gephyrocapsa oceanica. However, large coccolithophore species can be major contributors to coccolithophore community production even in low abundances. Here we fit an analytical equation, accounting for simultaneous changes in CO2 and light intensity, to rates of photosynthesis, calcification and growth in Scyphosphaera apsteinii. Comparison of responses to G. oceanica and E. huxleyi revealed S. apsteinii is a low-light adapted species and, in contrast, becomes more sensitive to changing environmental conditions when exposed to unfavourable CO2 or light. Additionally, all three species decreased their light requirement for optimal growth as CO2 levels increased. Our analysis suggests that this is driven by a drop in maximum rates and, in G. oceanica, increased substrate uptake efficiency. Increasing light intensity resulted in a higher proportion of muroliths (plate-shaped) to lopadoliths (vase shaped) and liths became richer in calcium carbonate as calcification rates increased. Light and CO2 driven changes in response sensitivity and maximum rates are likely to considerably alter coccolithophore community structure and productivity under future climate conditions.