Effect of UV-B exposure in eggs and embryos of patagonian anurans and evidence of photoprotection

PEROTTI, M.G. & DIÉGUEZ, M.C.

CHEMOSPHERE

Elsevier

Año: 2006 vol. 65 p. 2063 - 2070

0045-6535

In Patagonia, enhanced levels of ultraviolet radiation (UVR) are affecting not only the southernmost territories but the northern asIn Patagonia, enhanced levels of ultraviolet radiation (UVR) are affecting not only the southernmost territories but the northern as well, and there is a growing body of evidence indicating effects on terrestrial and aquatic communities. Anurans occur along a wide geo-well, and there is a growing body of evidence indicating effects on terrestrial and aquatic communities. Anurans occur along a wide geo-  graphical gradient in Patagonia and are common in shallow waters, usually breeding during spring when seasonal UV-B radiation is atgraphical gradient in Patagonia and are common in shallow waters, usually breeding during spring when seasonal UV-B radiation is at  its highest level. In this paper we analyse the effective irradiances (I) experienced in nature by eggs and embryos of the patagonian anu-its highest level. In this paper we analyse the effective irradiances (I) experienced in nature by eggs and embryos of the patagonian anu- rans Pleurodema bufoninum, Pleurodema thaul and Bufo spinulosus papillosus, considering water and egg jelly optical properties. Besides,rans Pleurodema bufoninum, Pleurodema thaul and Bufo spinulosus papillosus, considering water and egg jelly optical properties. Besides,  we determine photoprotective pigments in eggs and embryos of the different species, and ontogenetic shifts in pigment concentration.we determine photoprotective pigments in eggs and embryos of the different species, and ontogenetic shifts in pigment concentration.  Finally, we studied the effects of natural and enhanced levels of UV-B on eggs of P. bufoninum aiming to evaluate the role of the jellyFinally, we studied the effects of natural and enhanced levels of UV-B on eggs of P. bufoninum aiming to evaluate the role of the jelly  envelope in screening the damaging radiation. The evidence gathered in this work shows that natural and enhanced UV-B levels did notenvelope in screening the damaging radiation. The evidence gathered in this work shows that natural and enhanced UV-B levels did not  induce significant changes on the survivorship but incremented the occurrence of malformations. Also, the species experiencing highinduce significant changes on the survivorship but incremented the occurrence of malformations. Also, the species experiencing high  levels of exposure presented high concentrations of melanin suggesting that exposure to sunlight triggers photoprotection by pigments.levels of exposure presented high concentrations of melanin suggesting that exposure to sunlight triggers photoprotection by pigments. Collectively our results suggest that the studied species showed certain levels of adaptation to cope with high ambient UVR conferred byCollectively our results suggest that the studied species showed certain levels of adaptation to cope with high ambient UVR conferred by environmental and biological factors.environmental and biological factors.