Meeting Abstract
Antarctic zooplankton in freshwater lakes produce embryos capable of extended periods of dormancy when conditions are inhospitable for active life-stages. In light of this life history strategy, it is surprising that this study is the first extensive analysis of overwintering strategies, dormancy, and post-dormancy development in a freshwater Antarctic zooplankton. In the present study, post-dormancy development of embryos of Boeckella poppei was characterized using light and electron microscopy. The resulting developmental profile was used to assess the effects of anoxia and sub-zero temperatures on subsequent development and hatching success. Embryos of B. poppei survived incubation in native sediment at -12°C, but survivorship decreased at -24°C and no successful hatching occurred from embryos incubated at -80°C. In addition to sub-zero temperatures, embryos may face anoxic conditions in Antarctic lakes. The present study demonstrates that embryos continue to develop under severely hypoxic conditions, but can survive anoxic conditions for at least 90 days in a dormant state. To investigate the underlying mechanisms of dormancy and post-dormancy development, 31P-NMR was used to examine intracellular pH and phosphate containing compounds during resurrection from dormancy. Preliminary data demonstrates the existence of shifts in intracellular pH and phosphate containing compounds during the first 48 hours of post-dormancy development. This study establishes the foundation for research on the susceptibility of Antarctic freshwater zooplankton to climate change and anthropogenic influence.
