Freshwater ecosystems


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Freshwater ecosystems

  1. 1. Freshwater Ecosystems
  2. 2. Stream and river ecoSyStemS • Water in brooks, streams, and rivers may flow from meltingmelting ice or snow or come from a spring • Each stream of water that joins a larger stream is called a tributarytributary • As more tributaries join, the stream gets strongerstronger and becomes a river
  3. 3. stream tributary river
  4. 4. Pond and Lake ecoSyStemS Life Near Shore Littoral zone: area of water closest to the edge of a lake or pond Sunlight reaches bottom of littoral zone, making it possible for algae and plants to grow Beneath surface of water: algae Near shore: cattails and rushes Floating plants: water lilies Small animals: snails, insects, clams, worms, frogs, salamanders, turtles, fishes, and snakes
  5. 5. Littoral zone
  6. 6. Life Away from Shore Open-water zone: area of lake or pond that extends from littoral zone across top of water Goes as deep as sunlight can reach Home to bass, trout, and other fishes Many photosynthetic plankton live in this area
  7. 7. Deep-water zone: beneath open-water zone where no sunlight can reach Catfish, carp, worms, crustaceans, fungi, and bacteria live here These organisms often feed on dead organisms that sink from above
  8. 8. Three Zones of a Pond or Lake Open water zone Deep water zone
  9. 9. Wetland Ecosystems Wetland: area that is sometimes underwater or whose soil contains a great deal of moisture Play important role in flood control—soaks up large amounts of water during heavy rains Water in wetlands moves deeper into ground, so helps replenish underground water supplies
  10. 10. Marshes Treeless wetland ecosystem where plants, such as grasses, grow Common marsh plants: grasses, reeds, bulrushes, and wild rice Common animals: muskrats, turtles, frogs, and birds
  11. 11. Swamps Swamp: wetland ecosystem in which trees and vines grow Found in low-lying areas and beside slow-moving rivers Most swamps are flooded part of the year, depending on rainfall Swamp plants: poison ivy, orchids, water lilies Swamp animals: fishes, snakes, and birds
  12. 12. From a Lake to a Forest Did you know that a lake or pond can disappear? Water entering a standing body of water usually carries nutrients and sediment—these settle at the bottom of the lake Dead leaves and decaying matter also settle at bottom of pond or lake Bacteria decomposes this material
  13. 13. This process uses oxygen in the water Loss of oxygen affects the kinds of animals that survive in a pond or lake
  14. 14. Over time, pond or lake fills with sediment and plants start to grow in new soil Eventually, the wetland can become a forest
  15. 15. Marine ecosysteMs • Shaped by abiotic factors: water, temperature, water depth, amount of sunlight • Very diverse: ocean contains whales, the largest animals on Earth • Tiny plankton form the base of the ocean’s food chains
  16. 16. • Temperature – Temperature of ocean water decreases as depth of water increases – Surface zone is warm, top layer; surface currents mix the water – Thermocline in this zone, temperature decreases with increased depth – Deep zone bottom layer of water; averages a chilling 2 degrees C
  17. 17. Get in the Zone! • Major ocean zones: intertidal, neritic, oceanic, benthic • Intertidal Zone place where ocean meets land and is exposed to air for part of the day
  18. 18. • Neritic Zone ocean floor slopes downward, water is warm and receives lots of sunlight –Corals, sea turtles, fish, dolphins
  19. 19. • Oceanic Zone sea floor drops sharply, deep water – Animals often get food from material that sinks down from ocean surface
  20. 20. • Benthic Zone ocean floor; does not get much sunlight; very deep –Bacteria get energy from chemicals that escape from thermal vents on ocean floor
  21. 21. A Closer Look • Through evaporation, the ocean provides most of the water that makes up Earth’s precipitation
  22. 22. Intertidal Areas • Coral Reefs most found in neritic zone • Estuaries area where fresh water from streams and rivers spills into ocean – Fresh water and salt water are always mixing, so amount of salt in water is always changing
  23. 23. • The Sargasso Sea found in middle of Atlantic Ocean –Contains floating rafts of algae called sargassum
  24. 24. • Polar Ice the Artic Oceans and the ocean around Antarctica –Ice water rich in nutrients, which support large numbers of plankton