beginning of SS34TU0768S.html--> PHOTOMINERALIZATION OF ORINOCO RIVER PLUME DOM: A LATITUDE-DEPENDENT EMPIRICAL MODEL FOR THE ASSESSMENT OF POTENTIAL AMMONIUM YIELD Morell, J. M. University of Puerto Rico, oceano@coqui.net
Corredor, J. M. University of Puerto Rico, quimocea@caribe.net

 
PHOTOMINERALIZATION OF ORINOCO RIVER PLUME DOM: A LATITUDE-DEPENDENT EMPIRICAL MODEL FOR THE ASSESSMENT OF POTENTIAL AMMONIUM YIELD
 
Photomineralization of riverine DOM has been identified as source of dissolved inorganic nitrogen to marine phytoplankton. Although net DIN yield per UV irradiance unit is readily quantifiable for riverine end members, estimates of the spatially specific yield at a regional scale have not been proposed. We present estimates of the DIN yield of Orinoco River water as it spreads throughout the Eastern Caribbean. These estimates are based on an empirical relation describing the decrease in fluorescence yield observed simultaneously to the release of ammonium by the riverine end member upon exposure to natural UV irradiance. This approach assumes no oceanic production of fluorescent DOM above oceanic end member values and no other significant freshwater inputs to surface waters within the plume. Surface-dependent DIN input within the plume could explain the persistence of near-surface phytoplankton biomass enhancement several hundred kilometers from the river delta; a feature inconsistent with the observed early nitrate depletion of river plume waters upon transport into the southeastern Caribbean.
 
Day: Tuesday, Feb. 2
Time: Poster
Location: Sweeney Center
 
Code: SS34TU0768S