Studies on the effects of UV-B radiation on phytoplankton of sub-antarctic lakes and ponds

摘要

Experiments were performed to determine the effects of UV-B (ultraviolet, 280–320 nm) radiation on motility and growth of phytoplankton from lakes and ponds in South Georgia. After 4 h of solar radiation and 4h artificial radiation (UV-BBE11.6 kJ m-2day-1, UV-B lamps) the swimming velocity ofCryptomonassp. decreased. The growth rate ofBotryococcus, Lyngbyasp. andStauraslrumsp. did not show any significant variations between the different light conditions. The UV-B component was reduced by filtering solar radiation through glass bottles und cellulose acetate. Cloudy days had only 30 of the radiation of clear days in both the PAR (photosynthetic active radiation) and UV-B regions. The ponds contained large amounts of humic substances, which are responsible for the absorbance in the UV regio