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Life of a River - Biology
River Continuum Concept: Midstream (pg 4 of 7)

As a stream grows larger, its physical environment becomes more complex, as do its plant and animal communities.

By the time a stream has reached fourth through sixth order-a good stream to float a canoe or small boat-the gradient has probably decreased. The slower current is more suitable to a variety of organisms.

Sunlight strikes the full breadth of the river, producing a range of plants. These include rooted vascular plants of many kinds; algae known as periphyton attached to rocks, logs, and rooted plants; and free-floating algae known as phytoplankton. Leaves, twigs, and other detritus make up a smaller portion of the energy inputs. Of greater importance are the fine products of shredders, drifting down from upstream reaches.


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Introduction
Flow
Shape
Connections
Quality
Life
Description
Terrestrial plants
Terrestrial animals
Life cycles
Corridors
Refuges
Aquatic habitats
Adaptations
Continuum concept
Relationships
Consequences
Stories
Summary
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