Meeting Abstract
Recent data have shown that Lake Sutton contains an unstable zooplankton community that has decreased dramatically in biodiversity over the last three decades. This lake is a cooling reservoir contaminated with coal combustion residuals, which could be responsible for the current biological issues in the lake. Because cladocerans are one of the only zooplankton that show predictable patterns of abundance in the lake, we hypothesized that cladocerans have developed a natural resistance to toxicants in the lake. If that is true, non-native species will be impacted by putative toxicants in water and sediment collected from Lake Sutton. The present study addresses this by testing the susceptibility of the non-native cladoceran, Daphnia magna, and brine shrimp, Artemia franciscana, to native water and sediment from Lake Sutton. Toxicology protocols approved by the Environmental Protection Agency (EPA) test exposures of active zooplankton to putative environmental toxicants, but no standardized protocols address exposures of zooplankton during embryonic dormancy. In addition to testing the water using a standard EPA protocol for larvae of D. magna, ephippia of D. magna and dechorionated embryos of A. franciscana were exposed to Lake Sutton water and sediment during dormancy and early post-dormancy development. Exposure to Lake Sutton water did not increase mortality during early development in either species but did induce some abnormal development in A. franciscana. However, exposure of embryos to sediment from the lake during the hatching process caused high larval mortality. These data may explain why daphnids are one of the few stable zooplankton left in Lake Sutton.
