The Response of Freshwater Plankton Communities to Natural Levels of Ultraviolet Radiation

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WPC4 2 B P Z Courier 10cpi #| x v x 6 X @ 8 ; X @ HP DeskJet 500 HPDES500.PRS x @ x X , , 0 FX @Courier 10cpi 2 V @ Z F ` ? x x x , v x 6 X @ 8 ; X @ HP DeskJet 500 HPDES500.PRS x @ x X , , 0 FX @ #| x 2 2 This research will (1) characterize natural fluxes of UV B in lakes, and (2) experimentally manipulate natural UV B fluxes to resolve how plankton communities respond to UV B radiation. The results of this research will 1) establish solid baseline data on the attenuation of UV B radiation in freshwater lakes, 2) provide insights into the sensitivity and response of plankton communities to UV B fluxes, and 3) provide data on how future increases in UV B are likely to interact with other important ecological variables such as nutrient limitation and predation. Natural fluxes of ultraviolet radiation in the UV B range (280 320 nm) are known to be harmful to a wide variety of plants and animals and are increasing globally due to stratospheric ozone depletion. Organisms have already responded to current levels of UV B with the production of photoprotective compounds, photorepair of DNA, and behavioral avoidance. Although this response suggests that UV B is a potent ecological force, little is known about the ecology of UV B at the community or ecosystem levels, or even how far UV B penetrates freshwaters. %%% The combination of intensive experimentation in a few lakes, and the sampling of UV B and other limnological variables in a broad comparative study of numerous lakes, will strengthen our understanding of the role of UV B in freshwater ecosystems. ***