CS36 Ultraviolet Radiation
Date: Wednesday, June 12, 2002
Location: Poster Session - VCC
 
BaltanJJ, Moss Landing Marine Laboratories, Moss Landing, USA, jillbaltan@hotmail.com
Welschmeyer, N, A, Moss Landing Marine Laboratories, Moss Landing, USA, Welschmeyer@mlml.calstate.edu
 
PARTICULATE ULTRAVIOLET RADIATION ABSORPTION BY MYCOSPORINE-LIKE AMINO ACIDS IN COASTAL AND OPEN OCEAN ENVIRONMENTS OFF CENTRAL CALIFORNIA
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The relationship between particulate ultraviolet radiation (UVR) absorption and mycosporine-like amino acid (MAA) concentrations associated with temperate and subtropical phytoplankton communities was studied in the eastern Pacific Ocean. One winter cruise (February 1997) and two summer cruises (September 1997 and 1998) were conducted along a transect that originated in Monterey Bay, California. Two cruises extended 280 km offshore and the other extended 3800 km offshore. MAA concentrations were highest in the mixed layer and decreased below the limit of detection below the mixed layer. Particulate UVR absorption and total chlorophyll a concentrations were linearly related at the surface (R2 = 0.81). Results showed that in the mixed layer MAAs accounted for 40% of the variability in particulate UV absorption at onshore sites and 67% of the variability at offshore sites, where detrital particles were lower relative to phytoplankton biomass. The relationship between MAA concentrations and UV absorption deteriorated below the mixed layer, where UV absorbance by detrital material increased. MAAs can significantly contribute to the amount of particulate UV absorption in surface waters where phytoplankton are found.