Radiation amphibians

Carboniferous 345 Myr Climate cools, marked latitudinal gradients. Extensive forests of early vascular plants, especially club mosses, horsetails, ferns. Coal beds form. Amphibians diversify first reptiles appear. Radiation of early insect orders... 

Permian 290 Myr All land united in one large continent - Pangaea large glaciers form. Reptiles, including mammal-like forms, radiate amphibians decline diverse orders of insects evolve. Conifers appear. Mass extinction at end of period (ca. 95% of all species disappear)... 

Aukley, G.T., Diamond, S.A., and Tietge, J.E. et al. (2002). Assessment of the risk of solar ultraviolet radiation to amphibians. 1. Dose-dependent induction of hindhmb malformations in the Northern leopard frog Rana pipiens). Environmental Science and Technology 36, 2853-2858. 

Radiation adversely affects limb regeneration of amphibians, alters DNA metabolism, and increases the frequency of chromosomal aberrations and liver lesions (Table 32.25). In some species of amphibians and reptiles, as in many mammals, mortality rates after acute exposure to radiation do not stabilize within 30 days — effectively invalidating the conventional LD50 (30-day postexposure) value. In the rough-skinned newt (Taricha granulosa), for example, the minimal LD50 dose at 200 days after irradiation was 2.5 Gy, compared with 350 Gy at 30 days (Willis and... 

Table 32.25 Radiation Effects on Selected Amphibians and Reptiles... 

Lappenbusch 1976). Low temperatures seem to prolong the survival of amphibians exposed to ionizing radiation. The survival was greater of leopard frogs (Rana pipiens) held at low temperatures... 

B. Hileman, Amphibian population loss tied to ozone thinning. Chem. Eng. News March 7, 5 (1994) M. L. Bothwell, D. M. J. Sherbot, and C. M. Pollock, Ecosystem response to solar ultraviolet-B radiation influence of trophic-level interactions. Science 265, 97-100 (1994). 

Fernandez, M., L Haridon, J., Gauthier, L. Zoll-Moreux, C. (1993) Amphibian mieronueleus test(s) a simple and reliable method for evaluating in vivo genotoxic effects of freshwater pollutants and radiations. Initial assessment. Mutat. Res., 292, 83-99... 

Several amphibian species were examined for photolyase activity. This enzyme is responsible for the repair of DNA damage caused by UV-B radiation. A more than... 

Figure 26.4 Abiotic and biotic interactions leading to the indirect toxicity of chlorofluorocarbons to amphibians. Atmospheric release of chlorofluorocarbons causes the depletion of the stratospheric ozone layer (abiotic-abiotic interaction). Depleted ozone allows for increased penetration of UV-B radiation (abiotic-abiotic interaction). UV-B radiation alone and in combination with fungus (abiotic-biotic interaction) causes increased mortality of amphibian embryos.

Amphibian deformities related to chemicals, disease and radiation (Harris et ah, 1998a, b Dalton, 2002). 

Diamond et al. [127] have estimated UVR doses in wetlands using this approach. Typical UVR doses were estimated by first generating maximal solar radiation doses for each day using a radiative transfer model, SBDART [113]. The model produced values for the full spectrum of solar radiation, from 280 to 700 nm, for cloudless conditions. These maximal values were then modified based on cloud cover effect estimates from 30 yr of historical solar radiation data (National Renewable Energy Laboratory, Department of Energy http //rredc.nrel.gov/solar/). The values derived in this procedure were estimated daily terrestrial, spectral (2 nm increments from 280 to 700 nm) solar radiation doses. Water column doses were then derived from absorption coefficients and spectral attenuation data described by Peterson et al. [128]. Although the focus of this effort was to characterize risk of UV-B radiation effects in amphibians, the procedure is directly applicable to phototoxicity, and the resulting UV-A radiation and spectral doses could be directly incorporated into calculation of possible effects. 

S.A. Diamond, G.S. Peterson, J.E. Tietge, G.T. Ankley. Assessment of the risk of solar ultraviolet radiation effects on amphibians. III. Prediction of impacts in selected northern mid-western wetlands. Environ. Sci. TechnoL, submitted. 

G.S. Peterson, L.B. Johnson, R.P. Axler, S.A. Diamond. In situ characterization of solar ultraviolet radiation in amphibian habitats. Environ. Sci. Technol, submitted. 

Hatch (1998). Effects of ultraviolet radiation on amphibians Field experiments. Am. Zooi, 38,799-812. 

R. Hofer (2000). Vulnerability of fish and amphibians to ultraviolet radiation. Res. Adv. Photochem. PhotobioL, 1,265-282. 

E.M. Middleton, J.R. Herman, E.A. Celarier, J.W. Wilkinson, C. Carey, R.J. Rusin (2001). Evaluating ultraviolet radiation exposure with satellite data at sites of amphibian declines in Central and South America. Cons. Biol, 15,914-929. 

E.E. Little, R. Calfee, L. Cleveland, R. Skinker, A. Zaga-Parkhurst, M.G. Barron (2000). Photo-enhanced toxicity in amphibians Synergistic interactions of solar ultraviolet radiation and aquatic communities. J. Iowa Acad. Sci., 107, 67-71. 

E.E. Little, R.D. Calfee (April, 2000). The Effects ofUVB Radiation on the Toxicity of Fire-fighting Chemicals to Fish and Amphibians (Report to the U.S. Forest Service Wildland Fire Chemical Systems Program). Missoula Technology Development Center, Missoula, Montana. 

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