Ultraviolet and temperature effects on planktonic rotifers and crustaceans in northern temperate lakes

Abstract

1. Anthropogenic stressors such as climate change, ozone depletion and acidification may act in concert to alter ultraviolet (UV) light and temperature regimes in freshwater ecosystems. These physical and chemical changes will inevitably affect zooplankton community dynamics, but little is known about their relative effects on different species in natural communities. During spring, species that migrate to surface waters to take advantage of warmer temperatures may be especially vulnerable as UV levels can be high. 2. The objective of this study was to investigate the in situ effects of UV and temperature on a natural assemblage of planktonic rotifers and crustaceans during the spring. We performed in situ exposure experiments in two lakes with different surface temperatures. 3. Exposure to UV had a significant effect on the abundance and/or reproduction of four rotifers: Gastropus spp., Kellicottia bostonensis, Kellicottia longispina, Keratella spp.; two cladocerans: Holopedium gibberum, Daphnia catawba, and one copepod: Leptodiaptomus minutus. Incubation under cooler temperatures had a negative effect on K. longispina and H. gibberum. Temperature and UV had a significant interactive effect on abundance and/or reproduction of L. minutus and Ploesoma truncatum. Our results indicate that changes in underwater UV and temperature can significantly influence the composition of the zooplankton community and ultimately food web dynamics.

Extreme weather events alter planktonic communities in boreal lakes

“…This finding agreed with the reported suppression of copepods under warmed, fishless conditions (McKee et al 2002). Further, combined exposure to UV and cold temperatures can be advantageous for copepods, such as Leptodiaptomus minutus, that can rely on photoprotective pigmentation (Leech and Williamson 2000;Persaud and Williamson 2005).…”

Climate change and freshwater zooplankton: what does it boil down to?

“…Grazing may increase UV transparency through decreasing the density and altering the size structure of phytoplankton or decreasing the release of dissolved organic matter (DOM) by phytoplankton; thus, zooplankton can contribute to the development of a UV clear-water phase (Williamson et al 2007). UVR can also affect survival and fecundity of zooplankton (Leech and Williamson 2000;Grad et al 2003;Persaud and Williamson 2005), as well as alter abundance of food resources or predators (''solar cascade hypothesis ''-Williamson 1995;Williamson et al 1999).…”

Effects of Ultraviolet Radiation on Diel Vertical Migration of Crustacean Zooplankton: An in situ Mesocosm Experiment

“…Zooplankton survival and reproduction can be severely reduced at UVR levels found in the surface waters of highly-transparent lakes; however, effects are species-specific and may depend on other environmental factors such as temperature (Leech & Williamson, 2000;Williamson et al, 2002;Persaud & Williamson, 2005). In a laboratory experiment with monochromatic light, Storz & Paul (1998) found that Daphnia magna were positively phototactic to light from the visible spectrum but negatively phototactic to UVR.…”