Studies in preparation for space experiments on sea urchin embryos

This study carefully examines the parameters required for optimal fertilization and development of the sea urchin species, Strongylocentrotus purpuratus. A number of variations in the conditions for development have been tested to learn their effect on optimal embryonic development. Embryonic development was monitored for 48 hours (from single cell to late gastrula). The data collected through these observations have been used to construct two and three dimensional graphs that provided a profile of populations of embryos occurring at each developmental stage. This profile was used to accurately define both the time course and the morphological events that occur during 48 hours of development. This study will set the stage for comparative studies under zero gravity conditions (in space). The background studies done here provide an accurate population study of embryonic development that will permit a reliable evaluation of zero gravity conditions on embryonic development in space. They will allow us to differentiate between population abnormalities that normally occur on Earth, and the effects caused by zero gravity.