Main Research Topics - Global and Climate Change

The Ocean plays an important role as a buffer to global warning, by absorbing some 40 % of the CO2 released annually. This net uptake results from heating and cooling of surface waters (physical pump) and from biological uptake and export of organic carbon to the deep waters (biological pump).

Five phytoplankton taxons have been recently identified as important for understanding the functioning of the biological pump, the associated biogeochemical cycles (C, N, P, Si, S, Fe) and related impacts on climate change.

These are: diatoms, pico/nanophytoplankton, coccolithophorids, Phaeocystis, nitrogen-fixers. In recent years it has been also demonstrated that iron plays a crucial role in controlling phytoplankton production and the biological carbon pump in the HNLC (High Nutrient Low Chlorophyll) areas (40% of the global ocean).

Moreover it appears a co-limitation in vast regions of the remaining 60% of surface waters. Meanwhile the paradigm of a single limiting factor for some or all marine ecosystems has given way to the awareness of co-limitation by several nutrients simultaneously, where light deficiency as well as grazing losses furthermore play an important role.

Finally climate changes models predict that the Southern Ocean might be the last oceanic sink for atmospheric CO2.

In accordance, ESA research on global and climate change involves process-level experimental studies and complex ecosystem modelling. Both aim to an increased understanding of the mechanisms controlling the biological pump in the global ocean (EU-IRONAGES), with a focus on the Southern Ocean (BELCANTO) and ice-covered regions of the northern and southern polar oceans (SIBCLIM).