Research objectives and content
The Research objectives are to understand the role of dissolved organic nitrogen as a possible intermediate in the sequestration of the carbon in the ocean. We will try to define flows of transfer of the dissolved organic nitrogen pool in the marine environment and to quantify the main processes involved in the trophic system (excretion, biodegradation). We expect to determine what quantity of dissolved organic matter is really active and could be integrated in the classical diagram new- exportable production and could contribute to the carbon sequestration.
Training content (objective, benefit and expected impact)
The innovative aspect of this work will be the study the of dissolved organic nitrogen transfers by tracing several pathways of l5N-labeled dissolved inorganic and organic nitrogen through the food web. For that purpose, a new methodology (Slawyk & Raimbault 1995) will be used and will allow to measure enrichment in dissolved organic nitrogen. Furthermore, the specialization of the host institution on the study of dissolved organic carbon will allow me to undertake a simultaneous study of nitrogen and carbon cycles (and to follow the evolution of the C/N ratio in fluxes of matter), which is been carried out in very few teams of Research.