2. A
fresh water ecosystem is an aquatic
system that contains drinkable water or
water of almost no salty content. It has
habitats classified by different factors,
including temperature, light penetration,
and vegetation. Its resources include
lakes, ponds, rivers, streams, reservoirs,
wetlands as well as groundwater.
3. Kinds of freshwater habitats
Rivers,
–
–
–
streams
Flowing freshwater
Source: where it starts
Mouth: where it ends
Lakes,
ponds
Wetlands
4. All freshwater ecosystems
Just
–
a fraction of the Earth’s water
.01% = one one-hundredth of one percent
Occupy
surface
less than 1 percent of the Earth’s
5. Rivers and streams
More
than 3.5 million miles of rivers and streams
- Just the U.S.! More than 140 times around the Earth.
www.noaa.gov/str-plan/images/river.gif
6. Rivers
A river is usually cold and full of oxygen
and runs swiftly through a shallow
riverbed. As a river flows down a
mountain, a river may broaden, become
warmer, wider, and slower, and decrease
in oxygen.
8. Lakes and ponds
What’s
–
–
–
the difference?
Ponds typically smaller
May be seasonal—that is, dry up part
of the year
Lakes exist hundreds or thousands of
years
But,
even lakes can fill in or dry up
10. Parts of a lake
Littoral
–
–
zone: near shore
Nutrient rich, lots of plant and animal life
Warm
Limnetic
–
–
zone: near surface, open water
Lots of light
Lots of plankton
Profundal
zone: deeper, little light
Benthic zone: the bottom, little light, low
oxygen
12. Wetlands
Are
those areas that are inundated or
saturated by surface or ground water at a
frequency and duration sufficient to
support, and that under normal
circumstances do support, a prevalence
of vegetation typically adapted for life in
saturated soil conditions. Wetlands
generally include swamps, marshes,
bogs and similar areas."
14. What good are wetlands?
Help
–
–
clean water by acting like a filter
The plants and slow water flow in a wetland
help remove pollutants, leaving water
cleaner downstream in a lake or river.
Too much pollution can leave a wetland
toxic to visiting animals, such as many birds.
15. What good are wetlands?
Protect
shorelines
from
erosion
Erosion in
this case
came from
grazing
animals
The miles of rivers and streams in the United States is equivalent to more than 140 times the circumference of the earth – 140 trips around the equator.
Identify some of the regional rivers and streams known by the students.