The Effects of Ultraviolet-B Radiation on Aquatic Invertebrates

There is strong evidence that decreases in stratospheric ozone have led to increased ultraviolet-B radiation at the surface of the Earth. However, surprisingly little is known about the effects of UV-B radiation on aquatic ecosystems. The purpose of this study was to assess the sensitivity of aquatic invertebrates to UV-B radiation. Solar simulators were used to expose five species of aquatic invertebrates to enhance levels of UV-B radiation. The simulators were calibrated to match local ambient solar radiation. UV-B measurements in a eutrophic pond revealed that 90% of the irradiance was extinguished at approximately 30 cm depth. The irradiance at the upper 5-20 centimeters was comparable to levels used in the simulators. Median lethal dose (LD₅₀) values were determined for the cladocerans Ceriodaphnia reticulata, Scapholeberis kingii, and Daphnia magna, the ostracod Cyprinotus incongruens, and the amphipod Hyalella azteca. Among the species, 96-h LD₅₀ estimates were quite variable, ranging from 4.2 to 84.0 μW/cm². These estimates indicated S. kingii to be highly sensitive, H. azteca, C. reticulata, and D. magna moderately sensitive, whereas the ostracod C. incongruens was very tolerant to UV radiation. A survey of the distribution of S. kingii in Missouri ponds indicated that lightly pigmented individuals were restricted to turbid habitats, a finding consistent with the observation that light morphs could be induced at low light levels in culture. The sensitivity of both morphs to UV-B radiation was surprisingly similar. Overall, this study suggests that, in shallow ponds without physical refuges, UV-B radiation would have the strongest effects upon cladocerans and amphipods occuring in the water column, whereas ostracods would be better protected.

Name thesis:degree_name

Master of Science in Biology

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Biology

Year

1996

Author dc:creator

• Hurtubise, Robin D.

Contributors dc:contributor

• John Havel

• Biology

Statement dc:rights

• © Robin D Hurtubise

Repository record dc:identifier

https://bearworks.missouristate.edu/theses/89

OAI identifier oai:identifier

oai:bearworks.missouristate.edu:theses-1090