Organic Biogeochemistry
The biological pumping of carbon from the surface ocean to the deep sea plays a critical role in controlling atmospheric concentrations of carbon dioxide over decadal to millenial time scales. Our research is focused on deciphering marine biogeochemical processes that are recorded in the chemical structure, abundance and isotopic composition of organic molecules, known as biomarkers, in relation to climatic and environmental changes. Biomarkers are used as source/processes indicators and special emphasis is given upon shifts in plankton and microbial species composition, processes triggering and controlling organic matter production, transfer and fate in the water column and sediment during early diagenesis and burial and the prevailing hydrological, redox and climatic conditions. This line of investigation includes two major compartments: i) study of biogenic and anthropogenic organic compounds in the marine water column (dissolved, suspended, sinking particles), and iii) determination of organic compounds in marine sediments.
Marine Dissolved Organic Matter represents the largest pool of biologically active carbon on earth, in quantities equivalent to atmospheric CO2. We study the bio-physico-chemical processes that can alter the production, removal and storage of DOM, and ultimately have an important impact on the carbon exchange between the atmosphere and the oceans. Using state of the art analytical tools for measuring the optical properties of DOM (chromophoric/ fluorescent dissolved organic matter -CDOM/FDOM) we provide information on its chemical nature, sources, origins and biological reactivity. Our work is expanding on the seasurface microlayer of coastal waters. The specific chemical processes taking place at the thin (60 μm) seasurface film are part of our research. We focus on DOM seasonal cycling in this important microenvironment that connects the sea with the atmosphere.
