AQUATIC ECOSYSTEMS Determined by the salinity of water 2 types: Freshwater : lakes, ponds, rivers, streams, wetlands Marine: coastal marshes & swamps, coral reefs, oceans

CHARACTERISTICS Determines which organisms live where TEMPERATURE SUNLIGHT* OXYGEN NUTRIENTS Determines which organisms live where *Photosynthetic organisms live near the surface

Three types of organisms: based on location & adaptations Plankton Phytonplankton zooplankton Nekton Benthos

Plankton – microscopic drifters Phytoplankton: photosynthethic Algae (base of food chain) Zooplankton: heterotrophic microscopic organisms – jellyfish

Nekton – free-swimming

Benthos – bottom dwelling

Decomposers

7-1 Freshwater Ecosystems

These include rivers, streams, lakes, and ponds. Rivers and streams have moving water. The water may be moving fast or slow. Lake are usually larger and deeper than ponds. Just like in the oceans, plants and animals live in the shallow (less deep) parts. The sun shines more in the shallow parts.

Lakes & Ponds Littoral zone: near shore Nutrient rich Diverse life Plants rooted in mud, stems above water

Littoral zone

Lakes & Ponds Open water: Further from shore No rooted plants Phytoplankton starts food chain

Lakes & Ponds Deep Water: No light Bacteria & decomposers live on dead things that drift down Fish adapted to cool water

Lakes & Ponds Benthic Zone: Bottom Decomposers, insect larva, clams

How nutrients affect lakes Eutrophication= an increase in the amount of nutrients in an aquatic ecosystem. Plants & algae grow Bacteria feeding on decaying plants grow Bacteria use oxygen in water Reduced oxygen levels kills fish Run-off increase nutrients

Freshwater Wetlands Swamps – woody plants Marshes – non-woody Poorly drained land, Marshes – non-woody plants (cattails, grasses)

Function of Wetlands Trap & filter sediments, nutrients, pollutants Reduce flooding Buffer shoreline against erosion Spawning grounds & habitat for fish & shellfish Provide habitat for rare, threatened, endangered species Recreation

Human Impact Considered wasteland & breeders of disease carrying insects. Drained, cleared & developed. Now we recognize importance as water purifiers & flood prevention.

% of Wetlands lost . 22 states have lost 50% of wetlands7 have lost 80% (Indiana, Ill, Miss, Ky, Iowa, Calif, Ohio

Rivers Headwaters – origin may be snowmelt or rain Full of oxygen, runs swiftly through shallow riverbed Becomes wider, warmer, slower, contains more vegetation & less oxygen Communities & industries affect health of rivers.

Flint River

Lake Lanier

Atlanta’s drinking water

Characteristics of Aquatic Ecosystems