Seawater carbonate chemistry, biomass and metabolic rates (leucine incorporation, CO2 fixation and respiration) of Rhodobacteraceae (strain MED165) and Flavobacteriaceae (strain MED217) in a laboratory experiment

• Main Authors: Teira, Eva, Fernández, A, Alvarez-Salgado, Xose Anton, García-Martín, Enma Elena, Serret, Pablo, Sobrino, Cristina
• Format: Dataset
• Language: English
• Published: PANGAEA 2012
• Subjects: Abundance; standard error; Abundance per volume; Alkalinity; total; Aragonite saturation state; Bacteria; growth efficiency; Bicarbonate ion; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria (<20 L); Calcite saturation state; Calculated; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Carbon fixation rate; standard deviation; Cytophaga sp.; Fluorescence; dissolved organic matter; particulate organic matter; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Heterotrophic prokaryotes; Laboratory experiment; Laboratory strains; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.831372; https://doi.org/10.1594/PANGAEA.831372

Experimental results related to the effects of ocean acidification on planktonic marine microbes are still rather inconsistent and occasionally contradictory. Moreover, laboratory or field experiments that address the effects of changes in CO2 concentrations on heterotrophic microbes are very scarce, despite the major role of these organisms in the marine carbon cycle. We tested the direct effect of an elevated CO2 concentration (1000 ppmv) on the biomass and metabolic rates (leucine incorporation, CO2 fixation and respiration) of 2 isolates belonging to 2 relevant marine bacterial families, Rhodobacteraceae (strain MED165) and Flavobacteriaceae (strain MED217). Our results demonstrate that, contrary to some expectations, high pCO2 did not negatively affect bacterial growth but increased growth efficiency in the case of MED217. The elevated partial pressure of CO2 (pCO2) caused, in both cases, higher rates of CO2 fixation in the dissolved fraction and, in the case of MED217, lower respiration rates. Both responses would tend to increase the pH of seawater acting as a negative feedback between elevated atmospheric CO2 concentrations and ocean acidification.