Effects of pH on DNA Synthesis during Early Developmental Stages of the Purple Sea Urchin, Strongylocentrotus Purpuratus

Increasing levels of CO2 in the atmosphere are expected to contribute the continued drop in ocean pH, a process referred to as ocean acidification. Previous studies have shown fertilization and development of marine species can be significantly affected when the pH of sea water is artificially lowered (Pogano et al., 1985; Kurihara and Shirayama, 2004). The aim of this project is to assess the potential impacts that climate change will have on the development of the sea urchin, Strongylocentrotus purpuratus. The effects of decreased pH on cell cycle progression were examined by using artificial sea water buffered to a pH of 7.0, 7.5, and 8.0 to culture embryos for four hours after fertilization. Preliminary results show a significant decrease in observed cleavage and an increase in apoptotic embryos as the pH is lowered. In addition, we utilized the incorporation of a chemically modified nucleotide, BrdU, and a fluorescently tagged antibody to determine if the reduction in cleavage is a result of a blockage in DNA.