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

[[9818918]南极洲上空臭氧空洞的持续出现引发了许多研究，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海洋无脊椎动物浮游阶段的影响，如果有的话，受到的关注要少得多。对臭氧损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，北半球北纬地区的急剧下降已经被发现。本项目将利用实验室和实地研究，探讨太阳紫外线辐射引起的光氧化应激对缅因湾浅海潮下带两种优势棘皮动物配子、胚胎和幼虫的作用。与其他海洋生物一样，温带无脊椎动物含有类真菌菌素氨基酸（MAAs），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，所以它们在异养海洋无脊椎动物体内的来源是不确定的，但推测是来自它们的饮食。众所周知，微藻和各种海藻富含MAA，这些MAA的膳食来源可以转运到无脊椎动物组织，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MAA（尽管浮游营养的幼虫可以通过食用浮游植物获得额外的MAA），其浮游阶段自然暴露于比成年底栖生物群体更高剂量的紫外线辐射。海胆（strongyocentrrotus droebacachiensis）和海星（Asterias vulgaris）是缅因湾底栖生物群落的主要成员，它们从饮食中获取一套MAAs。本项目通过对这两种重要底栖动物的胚胎和幼虫进行实地和实验室实验，研究MAAs的积累是否能有效保护它们免受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生产的活性氧可以破坏各种细胞成分。将进行DNA光产物产生的测量和同时差分显示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）。这项工作的结果将对营养积累的紫外线吸收化合物的作用、DNA损伤、细胞周期基因对环境胁迫的分子反应以及暴露于紫外线光动力效应下的温带棘皮动物胚胎和幼虫的光氧化防御具有重要意义。紫外线辐射对底栖无脊椎动物不同生活史阶段的影响必须进行检查，以了解对底栖动物和海洋食物链的潜在生态后果，这是对底栖动物群落生态的真正关注，因为目前的预测表明，温带地区平流层臭氧的年减少将持续25年。

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.