Aquatic Ecosystems Chapter 7 Freshwater Ecosystem Determined by

Aquatic Ecosystems Chapter 7

Freshwater Ecosystem • Determined by salinity - amount of salt in the water • Freshwater include lakes, ponds, moving areas of rivers and streams, wetlands • Marine ecosystems include: marshes, swamps, coral reefs, and oceans

Groups of Life • Three groups within aquatic ecosystems include plankton, nekton, and benthos • Plankton - Organisms that float near the surface of the water • Nekton - free swimming organisms such as fish and turtles • Benthos - bottom dwelling organisms such as mussels, worms, and barnacles

Lake Zones • Littoral Zone - near the shore, nutrient rich • Benthic Zone - Bottom of a pond or lake

Eutrophication • Eutrophication is an increase in the amount of nutrients in an aquatic ecosystem • Eutrophic Lake - Lake that has a large amount of plant growth due to nutrients

Freshwater Wetlands • Freshwater wetlands areas that are covered with fresh water for at least part of the year • Include: • Marshes • Swamps

Marsh • The Everglades

Swamps • On flat land with lots of trees - good for amphibians and reptiles (alligators) • Mangrove Swamps - marine ecosystems dominated by trees with stilit-like roots

Flood Control • Flood Control - Environmental function of wetlands

Human Impacts • Originally considered wasteland • Have been drained, filled, and cleared for farms and development • Everglades once covered 8 million square acres, now only 2 million

Rivers • Start from melting snow capped mountains, cold and full of oxygen • As water hits level ground, becomes warmer and loses oxygen

Oxygen • Oxygen - Factor that determines where aquatic organisms live

Trout

Dams • Dams - Threats to river ecosystems

Rivers in Danger • Industries use rivers to dispose of waste • Farm runoff brings pollution to rivers

Marine Ecosystems • • • Estuaries Salt Marshes Mangrove Swamps Coral Reefs Rocky and Sandy Shores Oceans

Coastal Wetlands • Coastal land areas that are covered by salt water for all or part of the time

Estuaries • An area in which fresh water from a river mixes with salt water from the ocean

Salt Marshes • Salt marsh - Marine ecosystem dominated by marsh grasses

Rocky and Sandy Shores • Rocky Shores - More plants and animals • Sandy Shores - Sand dries out as tide recedes, organisms eat plankton trapped in sand

Coral Reefs • Cnidarians living in Calcium Carbonate Reefs • Corals - Uses stinging tentacles to capture prey

Oceans • Most life lives in shallow waters where sunlight is usable • Threats include overfishing and fishing techniques • Overfishing - Threat to ocean organisms • Artic Oceans - Where plankton prosper

• Which of the following in not an environmental function of wetlands? • Increasing runoff • Absorbing and removing pollutants from water • Trapping carbon that would otherwise be released into the air • Controlling floods

• Which of the following factors is not an important advantage for aquatic organisms living near the surface of a lake or pond? • Warmer temperature • More sunlight • Presence of decomposing organisms • Higher oxygen level

• Which or the following is not characteristic of salt marshes and mangrove swamps? • Both provide habitats for wildlife • Both are dominated by marsh grasses • Both are found along coastal areas • Both are threatened by development