Disentangling the role of the microbial pump on carbon cycling in the ocean: The Mediterranean Sea as a case study (MicroPump) – MicroPump

Assessing how the oceans sequester atmospheric carbon is a key challenge in biogeochemistry. Marine heterotrophic prokaryotes are key agents for this sequestration via the production of refractory dissolved organic matter (DOM) that persists in the ocean for years. This process, known as the microbial carbon pump, has particular importance in oligotrophic ecosystems, where an important fraction of fixed carbon is released as DOM. However, the processes that drive the microbial carbon pump are poorly known. MicroPump will assess the metabolic and environmental modulators of DOM production by marine prokaryotes, as well as its further bioavailability for natural microbial communities, in the Mediterranean Sea, an oligotrophic area highly vulnerable to climate change. Experimental work using model strains and natural communities, quantifying and characterizing DOM together with microbial diversity and gene expression, will be combined with a temporal study in the open NW Mediterranean sea as well as work with available Argo databases.