What do algae blooms mean for water quality?

Each spring and summer, low oxygen “dead zones” and harmful algae blooms appear in various parts of the Chesapeake Bay and its creeks and rivers. The size and severity of algae blooms and dead zones depend on the contents that runoff into the Bay. Runoff can bring nutrients and sediment from the land to the Bay in excessive amounts threatening aquatic life. Combined with high temperatures, the excess pollutants can fuel the growth of algae blooms and cause the water to become clouded and discolored.

Algae blooms make conditions difficult for much of the aquatic life in the Chesapeake Bay. A water condition called mahogany tide can cause the water to appear reddish brown. Mahogany tides may also deplete the water of oxygen making these areas inhabitable for aquatic life such as fish, oysters and crabs. For those who work and live in the Bay watershed, these blooms can cause sickness and skin irritation when in contact.

Even in scenarios where these blooms are non-toxic, they can still be harmful to the Bay. When algae blooms become dense enough, they block sunlight from reaching underwater grasses growing at the bottom of the Bay. Of course, underwater grasses are vital to the Bay's health, so when fewer grasses grow, the cycle of poor Bay health continues. When algae blooms die, they create more problems, as the decomposition process sucks up most of the oxygen that Bay organisms need to survive.

Since algae blooms are fueled by excess nutrients, any effort to prevent runoff from entering your local waterways can make a huge difference. Creating a personal rain barrel to collect and store rainwater can help keep runoff out of our rivers and streams. Other small steps such reducing fertilizing use on your lawn, picking up your pet's waste and planting more trees in your yard can help put a stop to these harmful blooms.