ENVIRNONMENTAL SCIENCE A

FRESHWATER ECOSYSTEMS - 4.3

• In a freshwater lake the areas with the most sunlight (littoral zone), sunlight provides the energy for photosynthesis in plants which form the base for all marine food chains.
• Wetlands along river bottoms have several important environmnetal functions; they provide habitat for wildlife, trapping casrbon that would otherwise be released into the atmosphere as carbon dioxide, absorbing floodwaqters, filtering out pollutatns, and providing many commerically important products.
• Most lakes found in North America were formed by glaciation that toook place during past ice ages.
• Run-off can pick up fertilizers from yards, and oil and gas off streets, the water can run into a sewer system and the pollutants are then put into the water systems.  If concertartions become high enough, these chemicals and other pollutants can affect plant and wildlife.

LOOK AT VOCABULARY FOR CHARACTERISTICS OF INDIVIDUAL ECOSYSYSTEMS