barrier islands
Long, thin, low offshore islands of sediment that generally run parallel to the shore along some coasts.
benthos/benthic
Bottom-dwelling organisms.
coastal wetland
Land along a coastline, extending inland from an estuary, 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/watershed
Land area that delivers water, sediment, and dissolved substances via small streams to a major stream (river).
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 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 seepage 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. Examples are turtles, fish, whales.
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, algae, or bacteria, found in aquatic ecosystems.
runoff
Fresh water from precipitation and melting ice that flows on the land into nearby streams, lakes, wetlands, and reservoirs.
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. Usually occurs along steep coastal areas where the surface layer of ocean water is pushed away from shore and replaced by cold, nutrient-rich bottom water.
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
Microscopic animals that swim or drift near the surface of aquatic environments.
bathyal zone
Dimly lit middle zone of the ocean that does not contain photosynthesizing producers because of a lack of sunlight. Sometimes referred to as the twilight zone.
abyssal zone
The deepest zone in the ocean characterized by extremely high pressures, low temperatures, low oxygen, few nutrients, and no sunlight.