1Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany
2The Ecosystems Center, Marine Biological Laboratory, Woods Hole, USA
Received: 18 Nov 2009 – Published in Biogeosciences Discuss.: 02 Dec 2009
Abstract. With the accumulation of anthropogenic carbon dioxide (CO2), a proceeding decline in seawater pH has been induced that is referred to as ocean acidification. The ocean's capacity for CO2 storage is strongly affected by biological processes, whose feedback potential is difficult to evaluate. The main source of CO2 in the ocean is the decomposition and subsequent respiration of organic molecules by heterotrophic bacteria. However, very little is known about potential effects of ocean acidification on bacterial degradation activity. This study reveals that the degradation of polysaccharides, a major component of marine organic matter, by bacterial extracellular enzymes was significantly accelerated during experimental simulation of ocean acidification. Results were obtained from pH perturbation experiments, where rates of extracellular α- and β-glucosidase were measured and the loss of neutral and acidic sugars from phytoplankton-derived polysaccharides was determined. Our study suggests that a faster bacterial turnover of polysaccharides at lowered ocean pH has the potential to reduce carbon export and to enhance the respiratory CO2 production in the future ocean.
Revised: 25 Apr 2010 – Accepted: 28 Apr 2010 – Published: 19 May 2010
Piontek, J., Lunau, M., Händel, N., Borchard, C., Wurst, M., and Engel, A.: Acidification increases microbial polysaccharide degradation in the ocean, Biogeosciences, 7, 1615-1624, doi:10.5194/bg-7-1615-2010, 2010.