An ecological community together with its environment,
functioning as a unit.
2. exotic species:
This is also known as "invasive" or "alien." Plant or
animal specie that is not native to the ecosystem under consideration
and whose presence causes or is likely to cause harm to the
environment, local economy, and human health.
The science that studies the properties, distribution,
and circulation of water. Hydrologists look at the various physical,
biological, and chemical processes that involve water as it
moves from the earth's atmosphere, to the oceans and rivers,
to below ground.
4. indicator species:
A species, be it plant or animal, whose
presence (or absence) indicates an ecosystem's biological condition.
Environmentalists might conclude from a dwindling indicator
species' population that pollution or degradation is damaging
Runoff pollution occurs when water from rainfall
or melting snow washes across the land, sweeping soil, bacteria,
pesticides, fertilizer, oil, and other toxic materials along
with it. This contaminated water "runs off" into local streams,
lakes, and rivers as well as groundwater wells.
6. water management:
Decreasing flooding of agricultural, residential, and commercial property; providing water for recreational activities; protecting fish and wildlife habitat; maintaining water quality; generating hydro-electric power.
7. water quality:
How do we know whether our oceans, rivers,
and lakes are safe to swim in, fish from, or use for drinking,
bathing, or farming? Scientists test water quality, or health,
by performing a battery of physical, chemical, and biological
tests. These tests measure everything from the levels of metals
and dissolved oxygen present to the temperature and color. Indicator
species can also show water quality.
An area of land that contains a common set of
streams and rivers that all drain into a single larger body
of water, such as a larger river, a lake, or an ocean. The Mississippi
River watershed is vast. All the tributaries to the Mississippi
that collect rainwater eventually drain into the Mississippi,
which eventually drains into the Gulf of Mexico.
An area where water covers the soil for most, if
not all of the year. The water-saturated soil determines the
kinds of plant and animal species that inhabit the area. Both
aquatic and terrestrial species inhabit wetlands. Wetlands generally
include swamps, marshes, bogs and similar areas.