Emma Bavoux

Evolution of the Suess Effect over the Anthropocene

The Suess effect is a human-induced phenomenon, it is the dilution of heavy carbon isotopes*, in the atmosphere (and the Ocean), due to the burning of fossil fuel. This phenomenon has been described as an atmospheric one, but since Earth's systems are linked, it is naturally ending up affecting the Ocean as well. The aim of this project is to identify which water masses are already affected by the Suess effect around the globe, and when & where will we be able to see a global signal in the Ocean and its sediment? To investigate, we need to look at the stable carbon isotope ratio of various samples from the Global Ocean. In a first step, the attention is focused on dissolved inorganic carbon (DIC) from many water samples, collected recently all over the ocean from several past expeditions. Later, we could look at sediment and carbonate archives like foraminifera or even corals.

    This project is in collaboration with Radhika Sudheendran from the Geosystem Modeling group at MARUM. With her work we will be able to see when the Suess effect will have a global spreading in the entire Ocean and model the future sedimentation.

    Why is this work important? The Suess effect is an anthropogenic phenomenon and the study of its spreading amongst the Earth’s systems, from the atmosphere, can help mankind realize even more the global impact of our societies. This project will also bring more keys for the stratigraphical recognition of the Anthropocene as a real geological unit, which is until today very debated in the geoscience community. Stratigraphers expressed the impossibility of describing a new epoch by the lack of a global signal in the sediment. With the study of the δ13C variation, and its future evolution (cf. Radhika Sudheendran PhD project) we could potentially use this geochemical global signal to describe the Anthropocene or its onset, just like it has been done with the Paleocene-Eocene Thermal Maximum (PETM).

*isotope 12C is the light one and 13C & 14C are the heavy ones