Meeting Abstract
Sea levels in North Carolina are currently higher than they ever have been and are still rising today (CCSP, 2009). Rising sea levels can increase the salinity levels in nearby freshwater habitats after major storm events. Frogs use these freshwater habitats to lay their eggs. Increases in salinization of these areas act as a stressor and could influence the growth and development, physiology, and behavior of the developing tadpoles. Frogs in Puerto Rico developing in high salinities showed higher mortality, decreased mass, and increased number of developmental abnormalities (Rios-Lopez, 2008). Understanding how stressors, such as increased salinity levels, affect amphibians is of particular importance due to the global amphibian decline. At minimum, a third of the world’s amphibian species are listed as threatened. Research to understand the sublethal effects of rising sea levels is important to help conserve this important group of animals. We hypothesize that increased salinity levels will adversely affect the physiology and behavior of developing tadpoles. To test this hypothesis, we exposed African clawed ( Xenopus laevis ) tadpoles to three treatments, which represent naturally occurring salinity levels: freshwater (control; 0 ppt), low salinity (5 ppt), or high salinity (10 ppt). During their development, each week the Gosner stage of development, snout-to-vent length, total length, and mass of each tadpole was measured. Locomotor activity was measured at premetamorphic (growth of trunk and tail, Gosner stage 31), prometamorphic (hindlimb development, Gosner stage 50), and metamorphic (development of forelimbs, Gosner stage 60) stages. We predicted that tadpoles exposed to high saline will have the greatest decline in growth and show the greatest change in locomotor activity compared to the freshwater and low salinity treatments.
