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

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，v x 6X@8；X@HP DeskJet 500 HPDES500.PRS x@x X，，0 fx@#|x 2这项研究将(1)表征湖泊中UV B的自然通量，并(2)通过实验操纵自然UV B通量，以解决浮游生物群落对UV B辐射的响应。这项研究的结果将1)建立关于淡水湖UV B辐射衰减的可靠基线数据，2)提供关于浮游生物群落对UV B通量的敏感性和响应的见解，3)提供关于未来UV B增加可能如何与其他重要的生态变量，如营养限制和捕食相互作用的数据。紫外线B波段(280 320纳米)的紫外线辐射天然通量已知对多种动植物有害，并且由于平流层臭氧消耗，全球范围内的紫外线辐射通量正在增加。生物体已经通过产生光保护化合物、光修复DNA和行为回避来对当前水平的UV B做出反应。尽管这种反应表明UV-B是一种强大的生态力量，但人们对UV-B在群落或生态系统层面的生态学知之甚少，甚至对UV-B穿透淡水的距离也知之甚少。在几个湖泊中进行的密集实验，以及在众多湖泊的广泛比较研究中对UV B和其他湖湖学变量的采样，将加强我们对UV B在淡水生态系统中的作用的理解。***

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. ***