Algae in the Wetlands

Types

• Three main types of algae exist. Chara and nitella algae are vertical algae that resemble underwater plants with roots. Filamentous algae grow in large strands and can form floating clumps or mats of algae that block waterways in the wetlands. Plankton algae are tiny, free-floating organisms that can make water look brown or green. These plankton algae are an important source of food for other organisms that live in the wetlands.

Algae Blooms

• In wetland areas where the level of nutrients in the water is high, algae can start to grow out of control. When these algae blooms occur, the water can turn blue-green or brown (in the case of plankton algae) or form mats that float on the water's surface. The excess of nutrients that leads to an algae bloom can be caused by fertilizers and detergents collecting in wetland areas; the blooms result in hypoxic or anoxic water and can cause fish kills or overtake native plants.

Algae and the Food Web

• Algae is critical to wetland ecology. As autotrophs (organisms that create energy from the sun's light), algae are primary producers in any wetland ecosystem. The majority of animals in the wetlands -- the consumers -- receive energy either directly or indirectly from algae. This occurs directly when an organism consumes algae or indirectly when an organism consumes another organism that has eaten algae.

What Eats Algae?

• Most of the wetland animals that eat algae are water insects, either in their larval stage or as adults that eat plants. Animals such as crayfish and ducks eat algae in addition to small invertebrates that live in the water. Some species of fish, such as mosquitofish, make algae part of their diet. Mollusks such as snails and tiny aquatic animals called zooplankton eat algae as well.