Premise of an Oceanic Revolution: Understanding the origin of pelagic calcification

The most abundant and diverse eukaryotic phytoplankton in modern oceans are diatoms, dinoflagellates and calcareous nannoplankton. However, this assemblage typified the oceans only since the Mesozoic. The transition from Palaeozoic to modern assemblage occurs in the Late Triassic (230-201 Myr ago). These newcomers increased the efficiency of organic matter exported from the ocean surface to the deep sea, introducing a powerful feedback to the Earth’s climate. During the same time interval, the supercontinent Pangea starts to break-up and extensive weathering of carbonate and evaporite sediments greatly affected the seawater chemistry.
The overall goal of this project is to evaluate the potential link between these changing environmental conditions and the emergence of planktonic calcification. In order to reach these goals, I want to (1) quantify the expansion of the calcifying plankton in the Oceans; (2) establish well calibrated curves of Mg and Li isotopes for the Late Triassic, which will more accurately record changes in silicate versus carbonate weathering (Li) and the amount of hydrothermal activity and evaporite dissolution (Mg) and (3) to reconstruct meaningful oceans’ response to evaporite and carbonayte dissolution.