Chapter 8 Flashcards
Saltwater (marine life zones)
(oceans and their bays, estuaries, coastal
wetlands, shorelines, coral reefs, and mangrove forests)
Freshwater life zones
(lakes, rivers, streams, and
inland wetlands).
Plankton
Saltwater and freshwater life zones contain several major types of organisms. One such type consists of weakly swimming, free-floating plankton, which can be divided into three groups.
Nekton
A second major type of organisms is nekton,
strongly swimming consumers such as fish, turtles, and whales
Benthos
The third type, benthos, consists of bottom-dwellers such as: oysters and sea stars, which anchor themselves to ocean bottom structures; clams and worms, which burrow into the sand or mud; and lobsters and crabs, which walk about on the sea floor.
Decomposers
A fourth major type is decomposers (mostly bacteria), which break down organic compounds in the dead bodies and wastes
of aquatic organisms into nutrients that aquatic primary producers can use.
Coastal zone
Is the warm, nutrient-rich, shallow water that extends from the high-tide mark on land to the gently sloping, shallow edge of the continental shelf (the submerged part of the continents).
Turbidity
This cloudiness, called turbidity, can occur naturally, such as from algal growth, or can result from disturbances such as clearing of land, which when it rains, causes silt to flow into bodies of water.
Estuaries
Are where rivers meet the sea.
Coastal wetlands
Coastal land areas covered with water all or part of the year—include river mouths, inlets, bays, sounds, coastal marshes (called salt marshes in temperate zones,
Intertidal zone
The area of shoreline between low and high
tides.
Open sea
The sharp increase in water depth at the edge of the continental shelf separates the coastal zone from the vast volume of the ocean.
Lakes
Are large natural bodies of standing fresh-
water formed when precipitation, runoff, streams, rivers, and groundwater seepage fill depressions in the earth’s surface.
Oligotrophic (poorly nourished) lakes
Lakes that have a small supply of plant nutrients.
Eutrophic (well-nourished) lake
A lake with a large supply of nutrients needed by producers.
Surface water
Precipitation that does not sink into the ground or evaporate.
Runoff
When precipitation flows into streams.
Watershed or drainage basin
Is the land area that delivers runoff, sediment, and dissolved substances to a stream.
Cultural eutrophication
Process in which human inputs of nutrients from the atmosphere and from nearby urban and agricultural areas can accelerate the eutrophication of lakes.
Mesotrophic lakes
Many lakes fall somewhere between the two extremes of nutrient enrichment.
Inland wetlands
Are lands located away from coastal
areas that are covered with freshwater all or part of the time—excluding lakes, reservoirs, and streams.
Aquatic life zones
The aquatic equivalents of biomes are called aquatic life zones—saltwater and freshwater portions of the biosphere that can support life.
