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EKOSISTEM AIR TAWAR Freshwater ecosystems

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20 diapositives · 784 Views · Jul 25, 2014

EKOSISTEM AIR TAWAR Freshwater ecosystems. SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ ecosystems . ppt ‎. Aquatic ecosystems. Key distinction: salinity = salt content of the water Measured in parts per thousand (ppt) 1 gm of salt in 1000 gms water = 1 ppt

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EKOSISTEM AIR TAWAR Freshwater ecosystems
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  1. EKOSISTEM AIR TAWARFreshwater ecosystems SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  2. Aquatic ecosystems • Key distinction: salinity = salt content of the water • Measured in parts per thousand (ppt) • 1 gm of salt in 1000 gms water = 1 ppt • FRESH usually < 0.5 ppt • OCEANS average 35 ppt • 0.5 to 17 ppt is called BRACKISH SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  3. Kinds of freshwater habitats • Rivers, streams • Flowing freshwater • Source: where it starts • Mouth: where it ends • Lakes, ponds • Wetlands SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  4. All freshwater ecosystems • Just a fraction of the Earth’s water • .01% = one one-hundredth of one percent • Occupy less than 1 percent of the Earth’s surface SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  5. Rivers and streams • More than 3.5 million miles of rivers and streams (including intermittent streams) • Just the U.S.! More than 140 times around the Earth. SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  6. Rivers from start to finish • Source = Headwaters • Can be: • Snowmelt • Spring • Even a lake • Water is colder, clearer, more highly oxygenated • Organisms include trout, mayflies • Mouth: where the river ends • Usually the ocean or another river, or lake • River widens and slows, getting warmer, siltier. • Middle is most diverse, lots of plants • Near mouth, increased sediment limits light and plants, water is warmest SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  7. Lakes and ponds • What’s the difference? • Ponds typically smaller • May be seasonal—that is, dry up part of the year • Lakes exist hundreds or thousands of years • But, even lakes can fill in or dry up SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  8. SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  9. Parts of a lake SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  10. Parts of a lake • Littoral zone: near shore • Nutrient rich, lots of plant and animal life • Warm • Limnetic zone: near surface, open water • Lots of light • Lots of plankton • Profundal zone: deeper, little light • Benthic zone: the bottom, little light, low oxygen SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  11. SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  12. Eutrophication • If nutrients increase too much in a lake, pond, or ocean, excessive plant growth results • Phosphorus • Nitrogen • NOT GOOD: why? • As plants decay, decomposing bacteria use oxygen dissolved in the lake to do their jobs. • Dissolved oxygen goes down SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  13. Wetlands: what are they? • For regulatory purposes under the Clean Water Act, the term wetlands means "those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs and similar areas." SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  14. Wetlands • May be fresh or brackish • Freshwater types include: • Marsh • Swamp • Bog • Fen SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  15. Marsh • Most common freshwater wetland in U.S. • Occur along streams or in depressions • Characterized by organic, wet soils and non-woody (i.e., no trees) vegetation. SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  16. Swamp Wetland dominated by woody plants SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  17. New Jersey wetlands • About 916,000 acres, or 19% of New Jersey, is wetlands, which seems like a lot; but the bad news is that about 40% of the original 1,500,000 acres has been lost to dredging and filling, dams, farming, development and highways. SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  18. What good are wetlands? • Reduce flooding by acting like sponges SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  19. What good are wetlands? • Help clean water by acting like a filter • The plants and slow water flow in a wetland help remove pollutants, leaving water cleaner downstream in a lake or river. • Too much pollution can leave a wetland toxic to visiting animals, such as many birds. SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎

  20. What good are wetlands? • Protect shorelines from erosion • Erosion in this case came from grazing animals SUMBER: https://apesatpvhs.wikispaces.com/file/view/Freshwater+ecosystems.ppt‎