Phytoplankton responses and associated carbon cycling during shipboard carbonate chemistry manipulation experiments conducted around Northwest European shelf seas

• Main Authors: Richier, Sophie, Achterberg, Eric Pieter, Dumousseaud, Cynthia, Poulton, Alex J, Suggett, David J, Tyrrell, Toby, Zubkov, Mikhail V, Moore, C M
• Format: Dataset
• Language: English
• Published: PANGAEA 2014
• Subjects: Alkalinity; total; Aragonite saturation state; Bicarbonate ion; Bottles or small containers/Aquaria (<20 L); Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; organic; particulate; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Chlorophyll a; Ciliates; Coast and continental shelf; Coccospheres; Community composition and diversity; Coulometric titration; D366_E1; D366_E2; D366_E2b; D366_E3; D366_E4; D366_E4b; D366_E5; D366_E5b; Diatoms; Dinoflagellates; Entire community; Event label; EXP; Experiment; Flag; Flagellates; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Identification; Laboratory experiment; Macro-nutrients; Nanoflagellates; heterotrophic; Nitrate; North Atlantic; OA-ICC; Ocean Acidification International Coordination Centre; Open ocean; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.840648; https://doi.org/10.1594/PANGAEA.840648

The ongoing oceanic uptake of anthropogenic carbon dioxide (CO2) is significantly altering the carbonate chemistry of seawater, a phenomenon referred to as ocean acidification. Experimental manipulations have been increasingly used to gauge how continued ocean acidification will potentially impact marine ecosystems and their associated biogeochemical cycles in the future; however, results amongst studies, particularly when performed on natural communities, are highly variable, which may reflect community/environment-specific responses or inconsistencies in experimental approach. To investigate the potential for identification of more generic responses and greater experimentally reproducibility, we devised and implemented a series (n = 8) of short-term (2-4 days) multi-level (>=4 conditions) carbonate chemistry/nutrient manipulation experiments on a range of natural microbial communities sampled in Northwest European shelf seas. Carbonate chemistry manipulations and resulting biological responses were found to be highly reproducible within individual experiments and to a lesser extent between geographically separated experiments. Statistically robust reproducible physiological responses of phytoplankton to increasing pCO2, characterised by a suppression of net growth for small-sized cells (<10 µm), were observed in the majority of the experiments, irrespective of natural or manipulated nutrient status. Remaining between-experiment variability was potentially linked to initial community structure and/or other site-specific environmental factors. Analysis of carbon cycling within the experiments revealed the expected increased sensitivity of carbonate chemistry to biological processes at higher pCO2 and hence lower buffer capacity. The results thus emphasise how biogeochemical feedbacks may be altered in the future ocean.