Aquest divendres tindrem amb nosaltres en Anna Rufas Blanco (Department of Earth Sciences, University of Oxford) que ens parlarà de: Towards a mechanistic understanding of the ocean biological carbon pump.

El seminari es farà en anglès.

Abstract

The ocean water column is a large sink of carbon and plays a primary role in mitigating the effects of climate change. The so-called biological carbon pump (BCP) contributes to lower atmospheric partial pressure of CO2 (pCO2) by taking it up and storing it in the ocean interior as particulate material. The BCP starting point is photosynthesis in the sunlit surface waters, which stimulates the production of biogenic particles by the marine food web. These particles sink away to the deep sea, carrying with them large amounts of carbon. During its downwards transfer, heterotrophic metabolism remineralises most of the sinking particulate flux, thus reducing the amount of carbon that is sequestered in the ocean.

Important as it is, we still do not understand the mechanisms by which climate-sensitive factors affect ocean interior remineralisation and, ultimately, atmospheric pCO2. Conventional biogeochemical models are unsuitable for that as they do not tackle the fundamentally discrete nature of marine particles, the mechanistic units of the BCP. Here I present a novel modelling approach suitable to gain insights into the dynamics of the BCP using a mathematical framework that tracks marine particles along their life history. The method allows us to record particle individual trajectories and observable attributes, hence obtaining quantitative views of their spatiotemporal distribution, composition and size spectra.