Effects of Ultraviolet Radiation on the Planktonic Life-History Phases of Benthic Echinoderms from the Gulf of Maine

Lesser 9818918南极上空持续出现的臭氧空洞引发了许多研究，这些研究证明了紫外线辐射对浮游植物群落初级生产的影响。紫外线辐射对任何生态系统中的海洋无脊椎动物的浮游阶段的影响，如果有的话，受到的关注要少得多。对臭氧消耗的关注使人们日益认识到紫外线辐射对海洋生物的单独和相互作用的影响。这些研究还表明，平流层臭氧消耗并不局限于南极。事实上，已经发现了北方半球北方纬度的急剧下降。该项目将解决，使用实验室和实地研究，太阳紫外线辐射诱导的配子，胚胎和幼虫的作用-两个占主导地位的棘皮动物从浅潮下带的缅因州湾的光氧化应激。与其他海洋生物一样，温带无脊椎动物含有类菌孢素氨基酸（MAA），可吸收与环境相关的紫外线辐射波长（310-360 nm）。MAAs不是在动物体内合成的，因此它们在异养海洋无脊椎动物中的起源尚不确定，但推测是来自它们的饮食。已知微藻和各种海藻富含MAA，并且这些MAA的膳食来源可以转移到无脊椎动物组织，特别是卵巢。这导致在新产卵的卵和发育中的胚胎或幼虫中有固定数量的甲基丙烯酸（尽管浮游幼虫可以通过捕食浮游植物获得额外的甲基丙烯酸），其浮游阶段自然暴露于比成年底栖生物更高剂量的紫外线辐射：人口。海胆，Strongy 1 ocentrotus droebachiensis和海星星，Asterias vulgaris是占主导地位的成员的底栖生物群落在缅因州，获得一套的MAA从他们的饮食。该项目通过对这两个重要的底栖物种的胚胎和幼虫进行实地和实验室实验，研究甲基丙烯酸的积累是否能有效地防止紫外线辐射的直接和间接影响。暴露于紫外线辐射导致光动力学产生的活性氧物质，可以破坏各种细胞成分。将进行DNA光产物产生的测量和同步差异显示PCR，以检查已知受紫外线辐射和氧化应激影响的差异表达基因（例如细胞周期和抗氧化剂）。这项工作的结果将有影响的作用，营养积累的紫外线吸收化合物，DNA损伤，细胞周期基因的分子响应环境压力，和光氧化防御的胚胎和幼虫的温带棘皮动物暴露于紫外线辐射的光动力效应。必须研究紫外线辐射对底栖无脊椎动物不同生命史阶段的影响，以了解对底栖生物和海洋食物链的潜在生态后果，这是对底栖生物群落生态的一个真正关切，因为目前的预测表明，在今后25年中，温带地区平流层臭氧将继续每年减少。

Lesser9818918The consistent occurrence of the ozone hole over Antarctica has initiated many studies that have demonstrated the effects of UV radiation on primary production of phytoplankton communities. The effects, if any, of UV radiation on the planktonic phases of marine invertebrates in any ecosystem has received considerably less attention. Concern about ozone depletion has resulted in a growing awareness of the separate and interacting effects of UV radiation on marine organisms. These studies have also shown that stratospheric ozone depletion is not restricted to the Antarctic. In fact, precipitous declines in northern latitudes of the Northern Hemisphere have already been detected. This project will address, using both laboratory and field studies, the role of solar ultraviolet radiation-induced photooxidative stress for gametes, embryos, and larvae of- two dominant echinoderms from the shallow subtidal zone of the Gulf of Maine. Like other marine organisms, temperate invertebrates contain mycosporine-like amino acids (MAAs), which absorb environmentally relevant wavelengths of UV radiation (310-360 nm). MAAs are not synthesized in animals, so their origin in heterotrophic marine invertebrates is uncertain, but presumed to be from their diet. It is known that microalgae and various seaweeds are rich in MAAs, and these dietary sources of MAA's can be translocated to the invertebrate tissues, especially the ovaries. This results in a fixed amount of MAA within the newly spawned eggs and developing embryos or larvae (although planktotrophic larvae could obtain additional MAAs from feeding on phytoplankton), whose planktonic phase is naturally exposed to higher doses of UV radiation than the adult benthic: population. The sea urchin, Strongy1ocentrotus droebachiensis and the sea star, Asterias vulgaris are dominant members of the benthic community in the Gulf of Maine that obtain a suite of MAAs from their diet. This project addresses whether the accumulation of MAAs provides effective protection from the direct and indirect effects of UV radiation using field and laboratory experiments on embryos and larvae from these two important benthic species. Exposure to ultaviolet radiation results in the photodynamic production of reactive oxygem species that can damage various cellular components. Measurements of DNA photoproducts production and simultaneous differential display-PCR to examine differentially expressed genes (e.g. cell cycle and antioxidant) known to be affected by exposure to UV radiation and oxidative stress will be conducted. The results from this work will have implications for the role of trophically accumulated UV absorbing compounds, DNA damage, the molecular response of cell cycle genes to environmental stress, and photooxidative defenses of embryos and larvae of temperate echinoderms exposed to the photodynamic effects of UV radiation. The effects of UV radiation on different life-history phases of benthic: invertebrates must be examined to understand the potential ecological consequences on the benthos, and in marine food chains, a genuine concern for the community ecology of the benthos as current predictions suggest that annual decreases in stratospheric ozone over temperate latitudes will to continue for the next 25 years.