The Effects of Ultraviolet-B Radiation on Freshwater Invertebrates: Experiments with a Solar Simulator

• Published in: Limnology and oceanography 1998-09, Vol.43 (6), p.1082-1088
• Main Authors: Hurtubise, Robin D., Havel, John E., Little, Edward E.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Ceriodaphnia reticulata; Conservation, protection and management of environment and wildlife; Cyprinotus incongruens; Daphnia magna; Environmental degradation: ecosystems survey and restoration; Fundamental and applied biological sciences. Psychology; Hyalella azteca; Irradiance; Lethal dose 50; Light; Mortality; Ponds; Radiation damage; Radiation dosage; Radiation tolerance; Scapholeberis kingi; Solar radiation; Zooplankton
• ISSN: 0024-3590; 1939-5590
• DOI: 10.4319/lo.1998.43.6.1082

There is concern that decreases in stratospheric ozone will lead to hazardous levels of ultraviolet-B (UV-B) radiation at the Earth's surface. In clear water, UV-B may penetrate to significant depths. The purpose of the current study was to compare the sensitivity of freshwater invertebrates to UV-B. We used a solar simulator, calibrated to match local ambient solar radiation, to expose five species of freshwater invertebrates to enhanced levels of UV-B radiation. UV-B measurements in a eutrophic pond revealed that 10% of the irradiance penetrated to 30-cm depth and 1% to 57-cm depth. The irradiance at the upper 5-20 cm was comparable to levels used in the simulator. Median lethal dose (LD50) values were determined for the cladocerans Ceriodaphnia reticulata, Scapholeberis kingii (two induced color morphs), and Daphnia magna; the ostracod Cyprinotus incongruens; and the amphipod Hyalella azteca. Among the species, 96-h LD50estimates were quite variable, ranging from 4.2 to$84.0 \muW cm^-2$. These estimates indicated S. kingii to be highly sensitive and H. azteca, C. reticulata, and D. magna to be moderately sensitive, whereas the ostracod C. incongruens was very tolerant to UV-B radiation. Overall, this study suggests that, in shallow ponds without physical refuges, UV-B radiation would have the strongest effects upon cladocerans and amphipods occurring in the water column, whereas ostracods would be better protected.