Articles | Volume 6, issue 9
Biogeosciences, 6, 1865–1875, 2009
https://doi.org/10.5194/bg-6-1865-2009

Special issue: The ocean in the high-CO2 world II

Biogeosciences, 6, 1865–1875, 2009
https://doi.org/10.5194/bg-6-1865-2009

  04 Sep 2009

04 Sep 2009

Influence of elevated CO2 concentrations on cell division and nitrogen fixation rates in the bloom-forming cyanobacterium Nodularia spumigena

J. Czerny, J. Barcelos e Ramos, and U. Riebesell J. Czerny et al.
  • Leibniz Institute of Marine Science, IFM-GEOMAR, Duesternbrooker Weg 20, Kiel, Germany

Abstract. The surface ocean absorbs large quantities of the CO2 emitted to the atmosphere from human activities. As this CO2 dissolves in seawater, it reacts to form carbonic acid. While this phenomenon, called ocean acidification, has been found to adversely affect many calcifying organisms, some photosynthetic organisms appear to benefit from increasing [CO2]. Among these is the cyanobacterium Trichodesmium, a predominant diazotroph (nitrogen-fixing) in large parts of the oligotrophic oceans, which responded with increased carbon and nitrogen fixation at elevated pCO2. With the mechanism underlying this CO2 stimulation still unknown, the question arises whether this is a common response of diazotrophic cyanobacteria. In this study we therefore investigate the physiological response of Nodularia spumigena, a heterocystous bloom-forming diazotroph of the Baltic Sea, to CO2-induced changes in seawater carbonate chemistry. N. spumigena reacted to seawater acidification/carbonation with reduced cell division rates and nitrogen fixation rates, accompanied by significant changes in carbon and phosphorus quota and elemental composition of the formed biomass. Possible explanations for the contrasting physiological responses of Nodularia compared to Trichodesmium may be found in the different ecological strategies of non-heterocystous (Trichodesmium) and heterocystous (Nodularia) cyanobacteria.

Download
Altmetrics
Final-revised paper
Preprint