Underwater Grasses

Underwater grasses grow in the shallow waters of the Bay and its streams. They provide food and habitat to wildlife, add oxygen to the water and trap sediment and nutrient pollution.

FAQ

  • What are underwater grasses?

    Underwater grasses, also known as submerged aquatic vegetation or SAV, are plants that grow in the shallows of the Chesapeake Bay.

  • How many types of grasses grow in the Chesapeake Bay?

    About 20 species of underwater grasses grow in the Chesapeake Bay and in lakes, streams, reservoirs and other bodies of water throughout the Bay watershed.

  • Why are underwater grasses important?

    Underwater grasses are a critical part of the Chesapeake Bay ecosystem because they provide food and habitat for countless species. They also help keep the water clear and healthy by absorbing nutrients, trapping sediments, reducing erosion and adding oxygen.

  • What animals depend on underwater grasses?

    Underwater grass beds form communities that provide food and shelter for many species. Fish, crabs and other animals visit grass beds to seek out food and find shelter from larger predators. Underwater grasses are also an important source of food for waterfowl such as ducks and geese.

  • How does a loss of underwater grasses affect other parts of the Chesapeake Bay?

    Underwater grasses are a critical part of the Chesapeake Bay ecosystem. Without them, underwater creatures such as fish and blue crabs do not have the shelter they need to survive, and migratory waterfowl do not have enough food to eat.

    Another important role of underwater grasses is to hold bottom sediments in place. If they are gone, waves can stir up bottom sediments and make the water cloudy. This can affect grass beds growing in other areas, because they need clear water to survive.

  • How can people save underwater grasses?

    People can help save underwater grasses by reducing the amount of pollution they contribute to the Chesapeake Bay and its rivers. Three ways you can pollute less are: fertilize your lawn less, plant a buffer of trees and shrubs around your property, and maintain your septic system (if you have one). Also, when boating, make sure you don’t disturb grass beds in shallow areas.

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Terms

  • Ecosystem

    A natural unit formed by the interaction of a community of plants and animals with the environment in which they live. All of the elements of an ecosystem interact with each other in some way, depending on each other directly or indirectly.

  • Erosion

    The disruption or movement of soil by wind, water or ice, occurring naturally or as a result of land use practices.

  • Molt

    An animal’s shedding of its exoskeleton prior to new growth. For example, blue crabs and other crustaceans must molt—or shed their shells—in order to grow.

  • Nutrients

    Chemicals that plants and animals need to grow and survive but, in excess amounts, can harm aquatic environments. Elevated levels of the nutrients nitrogen and phosphorous are the main cause of poor water quality in the Chesapeake Bay.

  • Photosynthesis

    The process by which plants convert carbon dioxide and water into carbohydrates and oxygen. These carbohydrates are used as energy by the plants or by organisms that consume the plants. Photosynthesis is also called primary production.

  • Precipitation

    Rain, snow, sleet or hail that falls to the ground.

  • Sediment

    Loose particles of sand, silt and clay that settle on the bottom of rivers, lakes, estuaries and oceans. Suspended sediment pushed into the water by erosion is one of the biggest impairments to water quality in the Chesapeake Bay.

  • Submerged aquatic vegetation (SAV)

    The technical term for bay grasses that grow underwater. SAV can improve water quality and provide food and habitat to fish, shellfish and waterfowl.

  • Zooplankton

    Planktonic animals that float in the water and range in size from single-celled protozoa to comb jellies. Zooplankton feed on detritus, phytoplankton and other zooplankton. They are eaten by fish, shellfish and whales.

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