Heterotrophic organisms are the driving force of the elemental recycling in the marine environment. In the oceans, the availability and the state (dissolved, particulate) of the elements are closely related to the organism activities (e.g., bacterial enzymatic activity).

In surficial sediments, biotic external factors such as bioturbation continuously modify the state of oxygenation and the bacterial activity rates. Among various abiotic external factors, light radiation is known to influence the molecular weight and the state of the organic compounds, but also to create molecular damages on proteins and intracellular DNA, thus modifying the bacterial growth rate.

In order to understand and model the organisms-OM interactions in the oceans, the aim of the Tranversal Axis is to promote the development of multidisciplinary works involving researchers of the three LMGEM research teams.