THE USE OF IN-SITU AND AIRBORNE FLUORESCENCE MEASUREMENTS TO DETERMINE BTV ABSORPTION-COEFFICIENTS AND DOC CONCENTRATIONS IN SURFACE WATERS

We compared the fluorescence (lambda(ex) = 355 nm, lambda(em) = 450 nm ) of chromophore-containing dissolved organic matter (CDOM) determined in the laboratory to that determined with a shipboard fluorometer and an airborne laser fluorosensor off the U.S. mid-Atlantic coast. Fluor escence was highly correlated with CDOM absorption at the excitation w avelength despite the presence of multiple sources of CDOM and a chang ing contribution of CDOM to the total dissolved organic C (DOC) pool, both in surface waters and down the water column. The mean quantum yie ld (0.8+/-0.1%) fell within the narrow range of yields previously dete rmined for U.S. east coast and south Florida waters. These results sho w that CDOM absorption can be reliably determined from in situ or airb orne fluorescence over wide areas of the ocean and that it may be poss ible to estimate DOC concentration from fluorescence or absorption mea surements.