9301322 PREZELIN This Accomplishment Based Project builds on prior studies which sought to 1) identify the sources and magnitude of variability in phytoplankton spectral properties which determine photosynthetic quantum yield, and 2) provide insights into how phytoplankton utilize radiant energy, influence the spectral characteristics of water-column optical properties and regulate rates of photosynthesis and photoinhibition. The major objectives of this accomplishment based renewal project are to: 1) further define the spectral linkages between quantum yield for photosynthetic charge separation, oxygen evolution and carbon fixation in different phytoplankters exposed to altered nutrient status, dynamic light fields and enhanced ultraviolet radiation; 2) to identify the mechanisms by which different spectral groups of phytoplankton respond photosynthetically to environmental change; and 3) to incorporate the findings into bio-optical models being developed in three independently funded field programs. The three field programs are: a) a study of algal pond mesocosm experiments in the Netherlands, b) along the coastal waters of the Palmer Peninsula, Antarctica on the time scale of years (the Antarctic LTER program), and c) during the austral spring in diverse phytoplankton biomes under the influence of the Antarctic ozone hole (Icecolors 93). ***
