A stream is an example of a freshwater aquatic ecosystem.
Streams can be formed from rainfall, snowmelt or natural springs. Some streams originate from wetlands.
The three major types of streams are perennial (water flows throughout the majority of the year), intermittent (water flows during the wet season and/or through half of the year) and ephemeral (water flows for a short time after strong storms or as snow melts).
Animals found in stream ecosystems include various species of fish, insects such as mosquitoes or water striders, and amphibians such as frogs.
Plants found in stream ecosystems include duckweed, hyacinth and types of water grasses.
The base of an energy pyramid in a stream includes primary producers such as plants and algae. Primary consumers include insects; secondary consumers include fish and amphibians; and tertiary consumers include turtles.