Dissolved oxygen is essential to the life of all aquatic organisms. Recent studies have shown the rapid decline of Dissolved oxygen (DO) in water sources after heavy precipitation. The main purpose of our investigation is to determine how heavy precipitation affects the biodiversity of marine life on Long Island. By determining the health of the ecosystem using indicator species (species that are more likely to be found in an oxygen-rich environment) following heavy precipitation, we will be able to determine when harmful conditions are present in our local waters.