Transcript 15.5 Estuaries and Freshwater Ecosystems

15.5 Estuaries and Freshwater Ecosystems
KEY CONCEPT
Freshwater ecosystems include estuaries as well
as flowing and standing water.
15.5 Estuaries and Freshwater Ecosystems
Estuaries are dynamic environments where rivers flow
into the ocean.
• An estuary is a partially enclosed body of water.
– mixture of fresh water with salt water
– Chesapeake Bay
– Louisiana bayous
– Florida Everglades
15.5 Estuaries and Freshwater Ecosystems
• Estuaries are highly productive ecosystems.
• Estuaries provide a protected refuge for many species.
– birds migration-use as refuge from cold weather
– spawning grounds-aka “nurseries of the sea”
• Estuaries are primarily threatened by land development.
15.5 Estuaries and Freshwater Ecosystems
Freshwater ecosystems include moving and standing
water.
• A watershed is a region of land that drains into a body of
water.
• Ecosystems may be different along a river’s course- ex.
Colorado River seen below
15.5 Estuaries and Freshwater Ecosystems
• Wetlands are among the most productive ecosystems.
– provide a home for many species
– filter dirty water
– renew underground water supply
15.5 Estuaries and Freshwater Ecosystems
Ponds and lakes share common features.
• Freshwater bodies are divided into three zones.
– littoral zone-( close to shoreline--similar to oceanic
intertidal)
– limnetic zone-open water further out from shore
– benthic zone-bottom of lake or pond (bacteria live here)
15.5 Estuaries and Freshwater Ecosystems
• All lakes “turn over” periodically.
– Turn over happens due to changes in density.
– In both autumn and spring, surface water flows
downward and bottom water flows upward.
– The upwelling brings up nutrients.