Marine and terrestrial biosphere are strongly controlled by climate but exert, in turn, a major influence on the Earth climatic system at all time-scales, through various biogeophysical and -chemical processes. As key components of global carbon and water cycles, ecosystems can in particular impact energy balance or the chemistry of ocean and atmosphere, with striking examples from the past (e.g., glacial cycles), present (anthropogenic CO2 sink), and future (carbon-climate feedback). Involving intricate direct and feedback processes, deciphering climate-biosphere interplays is complex but critical to anticipate how these components will respond to the unpreceded rate of anthropogenic-driven climate change.
Here we will target two iconic examples of the interplay between climate and marine biosphere in the past: (1) the K-Pg extinction event, and (2) changes in ocean oxygen content during the last Glacial cycle. Teaching will be structured around lectures and tutorials that will specifically address the relationship between marine ecosystems/carbon and carbonate cycles/ocean oxygen inventory, in the past as well as in the context of global change, as recorded by sedimentary archives and, in particular, marine microfossils. A practical lab session will be dedicated to the observation of coccolithophorids from the K-Pg event, and benthic foraminifera from oxygen-deficient environments (Oxygen Minimum Zones, Mediterranean sapropels).
K-Pg extinction event, OMZ, hypoxia, carbon cycle, carbonate cycle, microfossils
