The biological carbon pump revisited: feedback mechanisms between climate and the Redfield ratio
Omta, A. W., Bruggeman, J., Dijkstra, H. A. and Kooijman, S. A. L. M. 2006.
The biological carbon pump revisited: feedback mechanisms between climate and the Redfield ratio.
Geophys. Res. Let. 33: L14613
Abstract
Biological activity gives rise to a difference in carbon concentration
between the ocean surface and the deep waters. This difference is
determined by the carbon:nutrient ratio of the sinking organic
material and it is crucial in determining the distribution of
CO2 between the atmosphere and the ocean. For this reason,
it is interesting to determine whether the physical environment
affects the carbon:nutrient ratio of phytoplankton. Using a model with
a novel representation of the effect of temperature on phytoplankton
stoichiometry, we have investigated the influence of mixed-layer depth
and water temperature on the elemental composition of an algal
community. In the light-limited regime, the carbon:nutrient ratio
turns out decrease with increasing mixed-layer depth and
temperature. The effect of temperature on plankton stoichiometry
provides a positive feedback mechanism between temperature and
atmospheric CO2 content. This feedback may turn out to be
very important for understanding the CO2 changes during
glacial-interglacial transitions.