lesson 6.2-6.4

freshwater life zone

Aquatic system comprised of water with a dissolved salt concentration of no more than 1,000 ppm. Examples include standing bodies of fresh water such as lakes, ponds, and inland wetlands, and flowing systems such as streams and rivers. Compare biome.

Delta

Area at the mouth of a river built up by deposits of river sediments, often containing estuaries and coastal wetlands

coastal wetland:

Land along a coastline that is covered with water for all or part of the year. Examples include marshes and mangrove forests. Compare inland wetland.

watershed

Land area that delivers runoff, sediment, and dissolved substances to streams, lakes, or wetlands. Watersheds are also called drainage basins.

inland wetland

Land away from the coast, such as a swamp, marsh, or small pond, that is covered all or part of the time with fresh water. Compare coastal wetland.

brackish water:

Mixture of fresh water and salt water.

open sea:

Part of any ocean that lies beyond the continental shelf. Compare coastal zone.

estuary:

Partially enclosed coastal area where a river meets the sea and seawater mixes with fresh water.

surface water

Precipitation that does not sink into the ground or evaporate; fresh water that flows or is stored in bodies of water on Earth's surface. See surface runoff. Compare groundwater.

eutrophication

Process by which a body of water gains nutrients.

ocean acidification:

Rising levels of acidity in ocean waters, occurring because the oceans absorb at least 25% of the carbon dioxide emitted into the atmosphere by human activities, especially the burning of carbon-containing fossil fuels. The carbon dioxide reacts with ocean water to form a weak acid that can endanger entire ecosystems.

marine life zone:

Saltwater environment found in an ocean or its bay, estuary, coastal wetland, shoreline, coral reef, or mangrove forest.

runoff

Surface water that flows into freshwater life zones. See reliable surface runoff, surface runoff, surface water. Compare groundwater.

edge effect

Tendency for a transition zone between two different ecosystems to have greater species diversity and a higher density of organisms than are found in either of the individual ecosystems.

Permafrost

Underground soil where captured water can stay frozen for more than two consecutive years.

coastal zone:

Warm, nutrient-rich, shallow part of the ocean that extends from the high-tide mark on land to the gently sloping, shallow edge of the continental shelf. Compare open sea.

aquatic life zone

marine or freshwater portion of the biosphere