APES Module 2 - Aquatic Ecosystems

barrier islands

Long, thin, low offshore islands of sediment that generally run parallel to the shore along some coasts.

benthos

Bottom-dwelling organisms.

coastal wetland

Land along a coastline, extending inland from an estuary, that is covered with salt water all or part of the year. Examples are marshes, bays, lagoons, tidal flats, and mangrove swamps.

coastal zone

Warm, nutrient-rich, shallow part of the ocean that extends from the high-tide mark on land to the edge of a shelflike extension of continental land masses known as the continental shelf.

coral reef

Formation produced by massive colonies containing billions of tiny coral animals, called polyps, that secrete a stony substance (calcium carbonate) around themselves for protection. When the corals die, their empty outer skeletons form layers and cause the reef to grow. They are found in the coastal zones of warm tropical and subtropical oceans.

cultural eutrophication

Overnourishment of aquatic ecosystems with plant nutrients (mostly nitrates and phosphates) because of human activities such as agriculture, urbanization, and discharges from industrial plants and sewage treatment plants.

decomposer

Organism that digests parts of dead organisms and cast-off fragments and wastes of living organisms by breaking down the complex organic molecules in those materials into simpler inorganic compounds and then absorbing the soluble nutrients. Producers return most of these chemicals to the soil and water for reuse. Decomposers consist of various bacteria and fungi.

detritus

Parts of dead organisms and cast-off fragments and wastes of living organisms.

detritus feeder

Organism that extracts nutrients from fragments of dead organisms and their cast-off parts and organic wastes. Examples are earthworms, termites, and crabs.

drainage basin

See watershed.

estuary

Partially enclosed coastal area at the mouth of a river where its fresh water, carrying fertile silt and runoff from the land, mixes with salty seawater.

euphotic zone

Upper layer of a body of water through which sunlight can penetrate and support photosynthesis.

eutrophic lake

Lake with a large or excessive supply of plant nutrients, mostly nitrates and phosphates.

freshwater life zones

Aquatic systems where water with a dissolved salt concentration of less than 1% by volume accumulates on or flows through the surfaces of terrestrial biomes. Examples are standing (lentic) bodies of fresh water such as lakes, ponds, and inland wetlands and flowing (lotic) systems such as streams and rivers.

inland wetland

Land away from the coast, such as a swamp, marsh, or bog, that is covered all or part of the time with fresh water.

intertidal zone

The area of shoreline between low and high tides.

lake

Large natural body of standing fresh water formed when water from precipitation, land runoff, or groundwater flow fills a depression in the earth created by glaciation, earth movement, volcanic activity, or a giant meteorite.

mangrove swamps

Swamps found on the coastlines in warm tropical climates. They are dominated by mangrove trees, any of about 55 species of trees and shrubs that can live partly submerged in the salty environment of coastal swamps.

mesotrophic lake

Lake with a moderate supply of plant nutrients.

nekton

Strongly swimming organisms found in aquatic systems.

oligotrophic lake

Lake with a low supply of plant nutrients.

open sea

The part of an ocean that is beyond the continental shelf.

phytoplankton

Small, drifting plants, mostly algae and bacteria, found in aquatic ecosystems.

plankton

Small plant organisms (phytoplankton) and animal organisms (zooplankton) that float in aquatic ecosystems.

runoff

Fresh water from precipitation and melting ice that flows on the earth's surface into nearby streams, lakes, wetlands, and reservoirs. See reliable runoff, surface runoff, surface water.

surface water

Precipitation that does not infiltrate the ground or return to the atmosphere by evaporation or transpiration.

ultraplankton

Photosynthetic bacteria no more than 2 micrometers wide.

upwelling

Movement of nutrient-rich bottom water to the ocean's surface. This can occur far from shore but usually occurs along certain steep coastal areas where the surface layer of ocean water is pushed away from shore and replaced by cold, nutrient-rich bottom water.

watershed

Land area that delivers water, sediment, and dissolved substances via small streams to a major stream (river).

wetland

Land that is covered all or part of the time with salt water or fresh water, excluding streams, lakes, and the open ocean.

zooplankton

Animal plankton. Small floating herbivores that feed on plant plankton (phytoplankton).