Response of two marine bacterial isolates to high CO2 concentration

• Published in: Marine Ecology Progress Series
• Main Authors: Teira, Eva, Fernández, Ana, Álvarez-Salgado, Xosé Antón, García-Martín, Enma Elena, Serret, Pablo, Sobrino, Cristina
• Format: Article in Journal/Newspaper
• Language: English
• Published: Inter Research 2012
• Subjects: Bacterial metabolism; Flavobacteriaceae; Ocean acidification; Rhodobacteraceae
• Online Access: http://hdl.handle.net/10261/51029; https://doi.org/10.3354/meps09644

10 páginas, 3 figuras 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. This research was supported by the Xunta de Galicia (grant 07MMA013103PR) and the MICINN contract DIFUNCAR (CTM2008-03790). E.T. was funded by a Ramón y Cajal contract from the Spanish Ministry of Science and Innovation. C.S was funded by an Isidro Parga Pondal contract from the Xunta de Galicia. Peer reviewed