| Popis: |
A rapidly growing number of studies indicate that solar ultraviolet B radiation (280–320 nm, UV-B), at current levels, is harmful to aquatic organisms and may reduce the productivity of marine ecosystems (e.g. Siebeck et al. 1994; Hader 1997; DeMora et al. 2000). Such UV-B-induced decreases in productivity have been reported for bacterioplankton, phytoplankton, heterotrophs and zooplankton, the key intermediary levels of marine food chains (Damkaer 1982; Thomson 1986; Cullen and Neale 1994; Chalker-Scott 1995; Smith and Cullen 1995; Hader 1997). Analogous studies on the planktonic (often neustonic) early life history stages of crustacean zooplankton and ichthyoplankton, although much rarer, indicate that exposure to levels of UV-B currently incident at the earth’s surface could result in higher mortality that may lead to poorer recruitment to the adult populations of marine and freshwater fishes (Pommeranz 1974; Hunter et al. 1981; Hunter et al. 1982; Williamson et al. 1997; Walters and Ward 1998; Zagarese and Williamson 2000). This chapter focuses on the effects of UV (280–400 nm) radiation on crustacean zooplankton and ichthyoplankton in subarctic marine ecosystems. |
