All living things need nitrogen to grow. Nitrogen stimulates the growth of plants—both on land and in the ocean. In the marine environment, nitrogen jumpstarts blooms of algae—seaweed and phytoplankton, the tiny plants that form the base of the ocean food chain and provide half the oxygen we breathe. But an overdose of nitrogen triggers excessive growth of nuisance, and even harmful, algae. As these plants decay, bacteria take oxygen out of the water and release carbon dioxide into our coastal waters.
The map below shows concentrations of nitrogen around the Bay. There is a very clear trend of decreasing nitrogen away from shore. This indicates that land-based sources are contributing excess nitrogen to our waters. The farther offshore, the better the water quality!
Read the next section of the report Where Does All This Nitrogen Pollution Come From?