Plants need nitrogen to grow, but a significant portion of the nitrogen in fertilizers is not absorbed by the soil or used by the growing plants. Rather, it washes away into waterways, rivers, and the ocean. This in turn has had devastating effects on marine life. In some areas, excessive nitrogen in the oceans has caused algae blooms that kill wildlife, make it dangerous for people to consume fish or shellfish or in some cases even swim in affected waters. This problem isn’t limited to poorer countries. Nitrogen pollution is a serious problem here on Long Island. In our case, the nitrogen comes primarily from septic tanks and cesspools, although nitrogen from agricultural fertilizers also plays a role. Nitrogen pollution in the waters around Long Island has hampered fishing, made it dangerous to eat seafood from some areas, and caused environmental changes that make coastal areas more prone to flooding.