Navarro E, Robinson C T, Wagner B, Behra R
Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.
J Toxicol Environ Health A. 2007 May 1;70(9):760-7. doi: 10.1080/15287390701236454.
There is considerable concern about increasing levels of solar ultraviolet radiation (UVR) and the potential harmful effects of UVR on living organisms. Microcosm studies were conducted with algal biofilms and Scenedesmus vacuolatus cultures to examine the effects of increased UVR on freshwater algae. Because algae have evolved various strategies to minimize the potential damage induced by UVR, the sensitivity of an UVR ratio was evaluated using absorbance characteristics of algal extracts to short- and long-term responses of algae to UVR exposure. The effects of UVR on the photosynthetic activity of periphyton also were determined by fluorometry. Results showed various patterns: (1) a short-term decrease in the UVR ratio between UVR-absorbing compounds and chlorophyll-a that reflect damage from UVR, and (2) a long-term increase in the UVR ratio as communities change their photosystems by increasing UVR absorbance capabilities, and thereby cell protection. Results include (1) validation of the UVR ratio, (2) allowing assessment of different UVR exposure-induced effects to algae, and (3) providing mechanistic information on cellular strategies used by algae to reduce UVR-induced damages.
人们对太阳紫外线辐射（UVR）水平的不断上升以及UVR对生物有机体的潜在有害影响深感担忧。利用藻类生物膜和空星藻培养物进行了微观研究，以检验UVR增加对淡水藻类的影响。由于藻类已进化出各种策略来尽量减少UVR诱导的潜在损害，因此利用藻类提取物的吸光特性对藻类对UVR暴露的短期和长期反应来评估UVR比率的敏感性。还通过荧光测定法确定了UVR对周丛生物光合活性的影响。结果显示出不同模式：（1）反映UVR损害的UVR吸收化合物与叶绿素a之间的UVR比率短期下降，以及（2）随着群落通过提高UVR吸收能力从而实现细胞保护来改变其光系统，UVR比率长期增加。结果包括：（1）验证了UVR比率，（2）允许评估不同UVR暴露对藻类诱导的影响，以及（3）提供了有关藻类用于减少UVR诱导损害的细胞策略的机制信息。
