Seawater carbonate chemistry, nutrients, chlorophyll and diatom Proboscia alata during experiments, 2012

• Main Authors: Hoogstraten, Astrid, Timmermans, Klaas R, de Baar, Hein J W
• Format: Dataset
• Language: English
• Published: PANGAEA 2012
• Subjects: Alkalinity; total; standard deviation; Aragonite saturation state; Auto-analyzer; Technicon Traacs 800; Bicarbonate ion; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria (<20 L); Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; partial pressure; Chlorophyll a; Chlorophyll a per cell; Chromista; EPOCA; EUR-OCEANS; European network of excellence for Ocean Ecosystems Analysis; European Project on Ocean Acidification; Experimental treatment; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; International Polar Year (2007-2008); IPY; Laboratory experiment; Laboratory strains; Light; Light:Dark cycle; Southern Ocean; International Polar Year; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.778472; https://doi.org/10.1594/PANGAEA.778472

The combined effects of different light and aqueous CO2 conditions were assessed for the Southern Ocean diatom Proboscia alata(Brightwell) Sundström in laboratory experiments. Selected culture conditions (light and CO2(aq)) were representative for the natural ranges in the modern Southern Ocean. Light conditions were 40 (low) and 240 (high) µmol photons/m**2/s. The three CO2(aq) conditions ranged from 8 to 34 µmol/kg CO2(aq) (equivalent to a pCO2 from 137 to 598 µatm, respectively). Clear morphological changes were induced by these different CO2(aq) conditions. Cells in low [CO2(aq)] formed spirals, while many cells in high [CO2(aq)] disintegrated. Cell size and volume were significantly affected by the different CO2(aq) concentrations. Increasing CO2(aq) concentrations led to an increase in particulate organic carbon concentrations per cell in the high light cultures, with exactly the opposite happening in the low light cultures. However, other parameters measured were not influenced by the range of CO2(aq) treatments. This included growth rates, chlorophyll aconcentration and photosynthetic yield (FV/FM). Different light treatments had a large effect on nutrient uptake. High light conditions caused an increased nutrient uptake rate compared to cells grown in low light conditions. Light and CO2 conditions co-determined in various ways the response of P. alata to changing environmental conditions. Overall P. alata appeared to be well adapted to the natural variability in light availability and CO2(aq) concentration of the modern Southern Ocean. Nevertheless, our results showed that P. alata is susceptible to future changes in inorganic carbon concentrations in the Southern Ocean.