This year 270 proposals were submitted and 22 got funded; thus a success rate of only about 8%. The PI of the project is Federico Baltar, from the Microbial Oceanography group (https://www.microbial-oceanography.eu) at the Department of Functional & Evolutionary Ecology. The objective of the project is to address a fundamental unsolved problem in our understanding of the oceanic carbon cycle: what is the contribution and role of heterotrophic anaplerotic fixation in the production of new organic matter? Resolving this enigma could redefine the marine carbon cycle, by placing heterotrophs as an integral part of the global ocean, not only as consumers but also as key producers of new particulate organic carbon available for the marine food web.