Project description
Understanding the ocean’s metabolic balance
Approximately 98 % of the ocean’s biomass consists of microorganisms such as the minuscule algae phytoplankton. Phytoplankton’s role in Earth’s photosynthesis is essential because it captures carbon dioxide (CO2), allowing the ocean to release major living resources and dioxygen (O2). In addition, it triggers microbial respiration that is a fundamental metabolic process for counterbalancing photosynthesis and returning organic carbon as CO2. However, knowledge about microbial respiration remains limited. The EU-funded BULLE project will assess the ocean’s metabolic balance between photosynthesis and respiration by studying the evolution from CO2 production to 02, which is termed ‘respiratory quotient’ (RQ). The project will apply innovative technologies and methods to investigate how the chemical features of nutrients regulate the RQ in bacterial cells and study the interconnections between the RQ, net primary production and bacterial activities.
Objective
About 98% of the ocean’s biomass is composed of microorganisms like the tiny algae, phytoplankton. Tiny but mighty when it comes at capturing carbon dioxide (CO2). Phytoplankton acts for half of the Earth’s photosynthesis, allowing ocean’s to supply major living resources and dioxygen (O2). Microbial respiration is the other fundamental biological process that counterbalances photosynthesis and returns organic carbon back as CO2. Yet, despite ocean’s pivotal role in global climate, microbial respiration remains one of the least explored metabolic processes; so that, whether oligotrophic ocean is a net sink or source of CO2, is highly debated for the last 20 years. The BULLE project aims to evaluate the ocean’s metabolic balance between photosynthesis and respiration by looking at the production of CO2 evolved to that O2 consumed by marine bacteria, the so-called “respiratory quotient” (RQ). Limits of detection of biological CO2 production have left RQ measurements far behind the multitude of investigations of photosynthesis. BULLE will face these challenges using the most recent technologies. The project strongly relies on the multidisciplinary expertise I will share with my host lab to tackle this issue at both cellular and community level. Specifically, BULLE aims to (1) investigate how the chemical characteristics of nutrients (Fe and C) regulate the RQ in bacterial cells and (2) study the links between the RQ, net primary production and bacterial activities. An innovative aspect of BULLE is the implementation of continuous measurements of O2/N2 and pCO2 concentrations respiration, and the deployment of In Situ Oxygen Dynamic Autosampler (IODA) instrumentation in the coastal NW Mediterranean Sea. The training I will receive with BULLE will help me give my career a new direction from a lab expertise towards high resolution in situ observations. In return, I will transfer my experience in microbial metabolisms and radioisotopes tracking methods to the host team.
Fields of science
Programme(s)
Funding Scheme
MSCA-IF - Marie Skłodowska-Curie Individual Fellowships (IF)Coordinator
13284 Marseille
France