Theme 1 & 2
Project 2062

Carbon acquisition, allocation and processing by plankton in a high CO2 world
Project leader: Prof. dr. J.J. Middelburg
Researcher(s): Dr. A. de Kluijver
Starting date: 7-apr-08

Atmospheric CO2 concentrations have already increased from -280 to >380 ppm during the Anthropocene and will increase further to 500-1250 ppm at the end of this century depending on the socio-economic scenario. Oceans take up a large part of the excess CO2 with the consequence that surface ocean waters acidify. The biological consequences of ocean acidification are largely unknown, but important to investigate because these changes are essentially irreversible during our lifetimes. We propose to study the direct and indirect effects of high CO2 and low pH on natural plankton communities. We will make a cross-system analysis of phytoplankton characteristics, including elemental stoichiometry and isotopic composition. We will engage ourselves in large-scale mesocosm experiments with manipulated CO2 levels and perform some laboratory scale incubations with natural communities to investigate synergetic effects between high CO2 and elevated temperature and to study the carbon isotope fractionation among lipids, proteins and carbohydrates as a function of CO2. Moreover, we execute some dedicated deliberate tracer experiments with 13C and 15N to investigate the consequences of high CO2 on the transfer of carbon and nitrogen from primary producers to heterotrophic microbial consumers.

de Kluijver, A., Soetaert, K., Schulz, K. G., Riebesell, U., Bellerby, R. G. J., and Middelburg, J. J (2010). Carbon fluxes in natural plankton communities under elevated CO2 levels: a stable isotope labeling study. Biogeosciences Discussions7 (3): 3257-3295.
Darwin Center authors: de Kluijver A., Middelburg J.J., Soetaert K. E. R.

Anna de Kluijver (2012). Carbon flows in natural plankton communities in the Anthropocene.
Darwin Center authors: de Kluijver A.

A. de Kluijver, K. Soetaert, J. Czerny, K. G. Schulz, T. Boxhammer, U. Riebesell, and J. J. Middelburg (2013). A 13C labelling study on carbon fluxes in Arctic plankton communities under elevated CO2 levels. Biogeosciences10: 1425-1440.
Darwin Center authors: de Kluijver A., Middelburg J.J., Soetaert K. E. R.