THE IMPACT OF CLIMATE CHANGE AND OCEAN ACIDIFICATION ON THE BIOGEOGRAPHY OF FORAMIFERA

Abstract : Coupled-climate carbon cycle models (C4Ms) are linked to an eco-physiological model to determine the impact of climate-change and ocean acidification on the global 3D distribution of the most abundant foramifera species up until the end of this century. The eco-physiological model is used to estimate the growth-rate and abundance of eight distinct species of foramifera in response to temperature, light (for species with symbiotic algae), and food availability simulated by the four C4Ms. The models are forced using historical anthropogenic emissions and the high-emission IPPC AR4 scenario and all simulate a 2 to 20% reduction in global marine productivity and export production by 2100. In the first part of the study we present the change in both the distribution of the dominant species and their relative abundance in response to climate-change. In the second part, we additionally consider the influence of regional changes to the carbonate chemistry of seawater on the calcification rates of selected foramifera species, which allows us to also estimate the impact of ocean acidification on their biogeography.