Transcript Stream Organisms

10-3 Flowing-Water Ecosystems
Examples are rivers, streams, creeks
and brooks. All refer to water that
flows over land. Most aboveground
freshwater environments with
moving water are all referred to as
streams by scientists.
Stream Organisms
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These organisms are
adapted to the flow
of the stream in
which they live.
Some insect larvae
have hooks that allow
them to hold on to
plants.
Others have suckers
to hold on to rocks
and things.
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A lot of trout and
salmon have adapted
to live in streams.
Salmon live in oceans
but return to
upstream for
reproduction
purposes. Sometimes
dams block their way
back upstream.
Stream Organisms
Stream Flow
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Most streams begin at
high altitude and flow
downhill from mountain
tops because of gravity.
Most start from melting
snow.
Streams usually flow
towards oceans.
The “source” or “head”
is where the stream
begins.
Stream Flow
At the head of a stream, water
flow is fast and cold and full
of oxygen. As it flows
downhill, it slows down. As it
flows it picks up sediments
(small particles that settle to
the bottom of a body of
water). Sediments provide
place for plants to anchor
their roots. Plants growing
further cause the stream to
slow down. This then allows
phytoplankton to grow and
provides food for consumers.
Sedimentation and Erosion
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These cause a stream
to change its course
over time naturally.
As a stream meanders,
erosion takes place
along the fast-flowing
outer edge of the
stream. The inner edge
of the stream moves
more slowly depositing
sediment there. The
stream becomes
increasingly curved
with time.
Human Impact on Streams
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Dams made to form
reservoirs.
Dams formed to
channel water for
irrigation.
These acts result in
flooding and water
shortages which
affect the aquatic life
in the stream.