Disentangling the role of the microbial pump on carbon cycling in the ocean: The Mediterranean Sea as a case study (MicroPump) – MicroPump
Disentangling the role of the microbial pump on carbon cycling in the ocean: The Mediterranean Sea as a case study
Heterotrophic prokaryotes (HP) play a key role in dissolved organic matter (DOM) processing in the ocean, but little is known about their role as organic matter sources. The so-called microbial carbon pump (MCP) states that HP produce refractory DOM, this is, compounds that resist further remineralization and are thus stored in the ocean for thousands of years. However, the underlying mechanisms that lead to the production of DOM by HP and its persistence in the ocean are still unclear.
The main scope of MicroPump iss to address the mechanisms driving the microbial carbon pump in the ocean, with a closer look into HP-DOM dynamics in the Mediterranean Sea. Specific questions to be addressed are: <br /><br />1) Which are the major metabolic pathways for HP-DOM production? Is the production rate and quality (i.e. composition) of HP-DOM dependent on P or N limitation? WP1: HP-DOM production and its quality under C, N and P limitation. “Production experiments”<br />2) Which are the main agents and metabolic pathways for HP-DOM degradation? Which fraction of HP-DOM persists as refractory DOM? WP2. Assessing the bioavailability of HP-DOM in the field.<br />3) What is the importance of the MCP for surface and deep DOM accumulation in the Mediterranean Sea? WP3
To answer the project scientific questions, a multi-faceted approach was proposed, where experimental work with model strains and in situ microbial communities is combined with field observations in the Mediterranean Sea
1. Nawal Bouchachi, Ingrid Obernosterer, Barbara Marie, Olivier Crispi, Eva Ortega-Retuerta. Phosphorus limitation determines the quality of dissolved organic matter released by marine heterotrophic prokaryotes. In second revision in Limnol. Oceanogr. Letters (minor revisions)
2. Nawal Bouchachi, Barbara Marie, Olivier Crispi, Cecile Carpaneto.Bastos, Franck Li, Lorenzo Scenna, Ingrid Obernosterer, Eva Ortega-Retuerta. Bioavailabily of prokaryotic-derived DOM released under contrasting P availability. In prep. For Microbial Ecology
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.
Project coordination
Eva Ortega-Retuerta (Laboratoire d'océanographie microbienne)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
Partnership
LOMIC Laboratoire d'océanographie microbienne
Help of the ANR 212,965 euros
Beginning and duration of the scientific project:
March 2021
- 48 Months
