Area in aquatic biomes deeper than 200 meters so little light penetrates the water.
Biome that is based in the water, such as ponds, lakes, streams, or oceans.
Process of using the energy in chemical compounds to make food; characteristic of producers in ecosystems without sunlight.
Marine animals typically living in compact colonies of many identical individual polyps; includes the reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.
Underwater structures made from calcium carbonate secreted by corals; colonies of tiny living animals found in marine waters that contain few nutrients.
Partially enclosed body of water where fresh water from rivers and streams meets and mixes with salt water from an ocean.
Aquatic biome with a salt content of less than 1%; ponds and lakes, streams and rivers, and wetlands.
Source of a river or stream; the place where a river begins its journey.
Aquatic biome in the salt water of the ocean; also includes coral reefs and estuaries.
Part of the river where it empties into another body of water, such as another river, lake, bay, or ocean.
Area in an aquatic biome that extends to a maximum depth of 200 meters so that at least some light penetrates the water.
Process by which specific organisms (including all plants) use the sun's energy to make their own food from carbon dioxide and water; process that converts the energy of the sun, or solar energy, into carbohydrates, a type of chemical energy.
Land area that is saturated with water, either permanently or seasonally, with the characteristics of a distinct ecosystem.