Freshwater ecology


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Freshwater ecology

  2. 2.  Freshwater ecology  Types and limiting factors  Classification  Lentic communities  Lotic and springs
  3. 3. - The study of freshwaterecosystem - Freshwaterecosystems are a subset of Earth’s aquatic ecosystems. They include lakes, ponds, streams, springs, and wetlands.
  4. 4.  Freshwater habitats can be classified by different factors, including temperature, light penetration, transparency, etc. Freshwater ecosystems can be divided into lentic ecosystems and lotic ecosystems.  Classified on the basis of depth and flow of water
  5. 5.  A. Light Penetration  1. Aphotic zone  2. Photic zone  B. Distance from the shore and depth of the body of water  1. Limnetic zone  2. Profundal zone  3. Benthic zone
  6. 6.  C. Amount of Organic Matter  1. Oligotrophic – deep cold small surface area relative to depth nutrient-poor phytoplankton are sparse, not very productive don’t contain much life waters often very clear sediments low in decomposable organic matter  2. Mesotrophic - moderate nutrient content moderate amount of phytoplankton reasonably productive
  7. 7.  EUTROPHIC – shallow warm large surface area relative to depth nutrient-rich phytoplankton more plentiful and productive waters often murky high organic matter content in benthos leads to high decomposition rates and potentially low oxygen
  8. 8.  Temperature  Current - Largely determine the distribution if vital gases, salts and small organisms  Transparency - Turbidity  Can be measured using an instrument called a Secchi disk
  9. 9.  Concentration of respiratory gases - Oxygen and carbon dioxide concentration are often limiting in the fresh water environment  Concentration of biogenic salts  Nitrates and phosphates seem to be limiting in a freshwater ecosystem ; calcium and other salts
  10. 10.  Lentic ecosystem (Nonflowing water) Calm freshwater habitat or standing water; it refers to standing or relatively still water; from the Latin “lentus”, which means sluggish.  Lotic ecosystem (Flowing water) Washed or the running water; refers to flowing water; from the Latin ‘lotus’, to wash
  11. 11. Lakes Ponds Inland wetlands
  12. 12.  Lakes - is a body of relatively still fresh water of considerable size, localized in a basin, that is surrounded by land; vary in depth of 1m to more than 200 m  Formed by glacial erosion and deposition, shifts in Earth’s crust, uplifting ,ountains or displacing rock strata, craters of some extinct volcanoes, landslides  By nongeologic activity beaver dams streams to make shallow but often extensive ponds; humans create lakes by rivers and streams for power, irrigation or water shortage and smaller ponds for recreating fishing and wildlife
  13. 13.  Light penetration-influenced by silt and other materials and natural attenuation  Temperature-vary seasonally and with depth  Oxygen-can be limiting especially in summer, because only a small proportion of of the water is in direct contact with air and respiration by decomposers.  These three strongly influence the distribution and adaptations of life in lakes and ponds
  14. 14. Ponds- body of standing water, either natural or man-made, that is usually smaller than a lake.
  15. 15. Swamp - is a wetland that is forested
  16. 16. Bog - is a wetland that accumulates peat, a deposit of dead plant material—often mosses, and in a majority of cases, Sphagnum moss.
  17. 17.  The waters are usually flowing and exhibit a longitudinal gradation in temperatures, concentration of dissolved material, turbidity, and atmospheric gases, from the source to the mouth  Include rivers and streams (outlets of ponds and lakes); some emerge from glaciers and flows in a direction dictated by the lay of the land
  18. 18.  Spring – kind of freshwater habitat where water flows out of the ground
  19. 19.  River - is a body of water with current moving in one general direction.
  21. 21.  Stream- a thin body of water which has a continuous flow of water, often referred to as a creek or a brook.  TWO SUBHABITATS  1. Turbulent riffle – shallow water where velocity of current is great enough; site of primary production in the stream; periphyton or aufwuchs, diatoms, cyanobacteria, and water moss dominate
  22. 22. 2. Pool – deeper water where velocity of current is reduced; site of decomposition; major site of CO2 production during summer or fall necessary for the maintenance of a constant supply of bicarbonate in solution.
  23. 23.  Fast Stream  Streamlined form  Caddisflies, water moss(Fontinalis), hevy- branched filamentous algae  Slow Stream  Larval forms of insects have flattened bodies and broad flat limbs that enable them to cling to stones  Smallmouth bass with compressed bodies  Snails, burrowing mayflies, catfish, water striders
  24. 24.  Shredders – insect larvae that feed on coarse particulate organic matter (CPOM); includes caddisflies (Tricoptera) and stoneflies (Plecoptera)  Collectors – pick up the fine particulate organic matter (FPOM) from what shredders and microbes broken up,  Include filtering collectors and gathering collectors
  25. 25.  Grazers – feed on the algal coting of stones and rubbles ; includes the beetle larvae, water penny, and a number of mobile caddisfly larvae  Gougers – burrow into water-logged limbs and trunks of fallen tree
  26. 26.  Horizontal zone – obvious to the eye  Littoral zone – shallow water zone; surrounds most lakes and ponds, in which light reaches the bottom, stimulating the growth of rooted plants  Limnetic zone – open water; extends to the depth of light penetration; inhabiting this zone are microscopic phytoplanktons (autotrophs) and zooplanktons (heterotrophs) and nektons (free-swimming organisms)  Profundal zone – depth of light is compensated ; the point at which respiration balances photosynthesis; depends on a rain of organic material from the limnetic zone for energy
  27. 27.  Vertical zone – influenced by depth of light penetration  Benthic zone/bottom region – common to both littoral and profundal zones  Primary place for decomposition
  28. 28.  Limnetic Zone-  phytoplanktons like desmids, diatoms, filamentous algae  Zooplanktons like tiny crustaceans  Nektons like fish like summer fishes large mouth bass, pike, muskellurge; and winter fish like lake trout
  29. 29.  Depends on the temperature and availability of oxygen is limited because of depletion by decomposers  Only during spring and fall turnovers that life is abundant in this zones  Mostly decomposed substances are found here
  30. 30.  Organisms can tolerate cool temperatures and low oxygen levels  Anaerobic bacteria  Periphyton/Aufwuchs which colonize the leaves of submerged aquatic plants; on stones, woods froming a crustlike growth of cyanobacteria  Algae and diatoms are fast-growing and lightly attached
  32. 32. Nature with our intelligent help,can cope with man’s physiological needs and wastes, but she has no homeostatic mechanisms to cope with bulldozers, concrete, and the kind of agroindustrial air, water, and soil pollution that will be hard to contain as long as the human population itself remains out of control. (Odum, 1971p. 361st Ed.)
  33. 33. Thank You!!!