ECOSYSTEM RESPONSE TO SOLAR ULTRAVIOLET-B RADIATION - INFLUENCE OF TROPHIC-LEVEL INTERACTIONS

Solar ultraviolet radiation (UVR) can reduce the photosynthesis and gr owth of benthic diatom communities in shallow freshwater. Nevertheless , greater amounts of algae accumulate in UVR-exposed habitats than in UVR-protected environments. Near-ultraviolet (UVA wavelengths of 320 t o 400 nanometers) and mid-ultraviolet (UVB, wavelengths of 280 to 320 nanometers) radiation also inhibit algal consumers (Diptera: Chironomi dae). Larval chironomids are more sensitive to UVB than sympatric alga e. Differential sensitivity to UVB between algae and herbivores contri butes to counterintuitive increases in algae in habitats exposed to UV B. These mesocosm experiments illustrate that predictions of the respo nse of entire ecosystems to elevated UVB cannot be made on single trop hic-level assessments.