Shoreline erosion also adds sediment to the Bay. Land development, boat traffic and loss of shoreline vegetation can accelerate natural erosion. Nutrients , although vital to all ecosystems, can create problems when present in excessive amounts. Major sources of nutrients include sewage treatment plants, acid rain, agricultural fields and fertilized lawns. High levels of nutrients stimulate rapid growth of algae, known as blooms.
Algal blooms cloud the water and reduce the amount of sunlight reaching Bay grasses.
Certain types of algae grow directly on the plants, further reducing available sunlight. Historically, more than 200,000 acres of grasses grew along the shoreline of the Bay. By 1984, a survey of Bay grasses documented only 37,000 acres in the Bay and its tidal tributaries. Declining water quality, disturbance of grass beds and alteration of shallow water habitat all contributed to the Bay-wide decline. The absence of grasses translates into a loss of food and habitat for many Chesapeake Bay species.