Aquatic Ecosystems Chapter Seven Section One Freshwater Ecosystems

Characteristics Controlling factors: temperature, sunlight, oxygen, and nutrients determine what lives where Controlling factors: temperature, sunlight, oxygen, and nutrients determine what lives where Organisms are grouped by location and adaptations Organisms are grouped by location and adaptations Plankton: float near the surface Plankton: float near the surface –Phytoplankton – produce most of the food –Zooplankton – microscopic animals

More Characteristics Nekton – free swimming organisms such as fish and turtles Nekton – free swimming organisms such as fish and turtles Benthos – bottom dwelling organisms such as clams, worms, and barnacles Benthos – bottom dwelling organisms such as clams, worms, and barnacles –Usually attached to the bottom

Lakes and Ponds Formed by nature, beavers, humans Formed by nature, beavers, humans Photosynthesis by plants Photosynthesis by plants Types of organisms determined by amount of sunlight Types of organisms determined by amount of sunlight

Lakes and Nutrients Eutrophication – increase in the amount of nutrients in an aquatic ecosystem, runoff is major cause but happens naturally Eutrophication – increase in the amount of nutrients in an aquatic ecosystem, runoff is major cause but happens naturally Eutrophic lake – too many plants due to excess nutrients Eutrophic lake – too many plants due to excess nutrients Too many plants leads to too many bacteria and they use all the oxygen Too many plants leads to too many bacteria and they use all the oxygen

Freshwater Wetlands Areas of land covered by fresh water at least part of the year Areas of land covered by fresh water at least part of the year Marshes contain non-woody plants like cattails Marshes contain non-woody plants like cattails Swamps contain woody plants like trees Swamps contain woody plants like trees Habitat for many plants and animals Habitat for many plants and animals

Functions of Wetlands 1. Trap and filter sediment, nutrient and pollution; keep out of lakes & oceans 2. Prevent floods, absorb water 3. Protect shorelines 4. Habitat for many species 5. Recreational activities

Marsh Wetland with nonwoody plants Wetland with nonwoody plants Most are in southeastern US (Everglades) Most are in southeastern US (Everglades) Low flat areas with little water movement Low flat areas with little water movement Benthic zone rich in nutrients Benthic zone rich in nutrients Many types of birds Many types of birds Type of marsh determined by salt content or salinity Type of marsh determined by salt content or salinity

Swamps On flat, poorly drained land often near streams On flat, poorly drained land often near streams Woody shrubs or water-loving trees depending on latitude Woody shrubs or water-loving trees depending on latitude Mangrove swamps in warm climates Mangrove swamps in warm climates Many kinds of organisms: plants, birds, reptiles, amphibians Many kinds of organisms: plants, birds, reptiles, amphibians

Human Impact on Wetlands People used to think they were wastelands only good for breeding insects People used to think they were wastelands only good for breeding insects Many have been drained and filled: Everglades were 8 million acres, now 2 million Many have been drained and filled: Everglades were 8 million acres, now 2 million US government and most states now protect wetlands US government and most states now protect wetlands

Rivers Many come from snow melt Many come from snow melt Usually cold, swift, full of oxygen at headwaters Usually cold, swift, full of oxygen at headwaters Broadens, warms and slows as it comes down Broadens, warms and slows as it comes down Runoff washes nutrients and sediments into rivers from farms Runoff washes nutrients and sediments into rivers from farms Very susceptible to many kinds of pollution Very susceptible to many kinds of pollution