Effects of long-term ultraviolet radiation: the white form of Metridium senile (Anthozoa: Actiniaria) as a potential biological indicator for ultraviolet

Abstract

Genetically identical individuals of the white form of Metridium senile were kept in the laboratory for 40 months, during almost 2 years of which they were irradiated with ultraviolet (UV) radiation simulating the shape of the solar UV spectrum. The living and experimental conditions were largely matched to the conditions in the sea anemones' natural habitat on the North Sea coast. Controls were shielded from direct radiation or irradiated with only the visible range of the spectrum; for the UV tests, the UV component corresponded either to the conditions in the natural habitat or to twice or 4 times this dose. All experiments were preceded by a severalmonth settling-in period, and UV irradiation was always begun at a low intensity. Under these conditions UV was not lethal but produced many parameter changes, of which only those that were irreversible for the entire duration of the experiment, from September 1992 to August 1994, are described here. The body mass fell significantly in all three UV-radiation modes. All irradiated animals positioned themselves so as to be less exposed to the radiation, and all changed colour from white to brown. These responses are discussed with reference to the potential of M. senile as an indicator or monitor for UV in the northern European coastal region. Field analyses are currently being conducted to demonstrate the extent to which the present results apply to field conditions.

Stress protein (HSP70 family) expression in intertidal benthic organisms: the example of <i>Anthopleura elegantissima</i> (Cnidaria: Anthozoa)

“…The potential tissue damage resulting from UV exposure in A. elegantissima is ameliorated by the production of UV-absorbing micosporine-like amino acids (Stochaj et al, 1994;Banaszak and Trench, 1995), and further protection from UV damage in this species occurs via elevated catalase and superoxide dismutase activites in animal tissue (Dykens and Shick, 1984). It will be of great interest to test HSP expression under different field UV exposures, as UV can potentially damage anemones (Metridium senile: Westholt et al, 2001). Although it has been surmised that outside A. elegantissima polyps encounter more stress due to more exposed surfaces during emersion, this is not reflected in our results (Fig.…”