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Effects of ultraviolet-B radiation and pH on early development of the moor frog Rana arvalis

  • Maarit Pahkala
  • Anssi Laurila
  • Lars Olof Björn
  • Juha Merilä
Publishing year: 2001
Language: English
Pages: 628-636
Publication/Series: Journal of Applied Ecology
Volume: 38
Issue: 3
Document type: Journal article
Publisher: Wiley Online Library

Abstract english

Although the potential negative effects of increased ultraviolet-B (UV-B) radiation on early life stages of aquatic organisms are widely recognized, possible synergistic effects with other stressors have seldom been studied outside the laboratory. We investigated the effects of UV-B radiation and pH on hatchability and early development of moor frog Rana arvalis eggs in the field and in laboratory experiments conducted during April 1998 and April 2000 in central Sweden. 2. In the field experiments, no evidence was found for reduced hatchability or increased frequency of developmental anomalies of embryos exposed to ambient levels of UV-B compared with embryos shielded from UV-B radiation. 3. Hatchlings shielded from ambient UV-B radiation did not grow larger than their exposed full-sibs, giving no support to the hypotheses that (i) the repair of cellular UV-B damage might be energetically costly nor (ii) that UV-B-induced photoproducts directly reduce growth. 4. Although low pH (50) reduced hatchability, increased frequency of developmental anomalies and reduced early embryonic growth in R. arvalis, there was no evidence for synergistic effects of pH and UV-B on any of these traits. 5. The lack of UV-B radiation effects on the development of R. arvalis embryos cannot be ascribed to relatively low effective daily doses of radiation (c. 043 kJ m2) during the field experiments, as in the laboratory even higher doses at UV-B 125 kJ m2 and 158 kJ m2 (all DNA weighed) had no negative effects. 6. These results suggest that current levels of UV-B radiation in northern Europe are not likely to reduce fitness in natural populations of the moor frog, even in areas already stressed by acidity.


  • Biological Sciences


  • ISSN: 1365-2664
Lars Olof Björn
E-mail: lars_olof [dot] bjorn [at] biol [dot] lu [dot] se

Professor emeritus

Molecular Cell Biology

+46 46 222 72 53