Chromophoric dissolved organic matter (CDOM), the colored fraction of the dissolved organic matter (DOM) pool, plays an important role in and affects our interpretation of the biogeochemistry of the open sea. Light absorption by CDOM drives photochemical reactions affecting many radiatively important trace gases (CO2, DMS, COS, CO, etc.). Further, light absorption by CDOM often hinders our ability to diagnose biogeochemical processes from satellite ocean color imagery. Our research is focused on CDOM cycling in the open ocean (surface and deep waters) far from terrestrial influence.
To date we have described the global distribution of CDOM in the surface and deep ocean, and inferred (by observation and experiment) the processes controlling its abundance and distribution, including in situ sources, deep ocean circulation, and photolysis at the surface.
We are now focusing this descriptive effort toward the chemical transformations that occur during the processes that regulate CDOM abundance, distribution and optical characteristics. DOM is a complex mixture of biopolymers and geopolymers whose chemical composition is only now being revealed by state-of-the art techniques.
The project began in the spring of 2003. At present we are on our second “round” of funding from NSF and NASA. Renewal proposals to both agencies are pending (Fall 2008). If successful we will be extending our work into more thorough characterization of CDOM using state of the art geochemical techniques, in collaboration with the organic geochemistry group at ODU.