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Ch 19 ppt


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Ch 19 ppt

  1. 2. The Seafloor Section 1
  2. 3. Seafloor geography <ul><li>Continental shelf – the gradually sloping end of a continent that extends under the ocean </li></ul><ul><ul><li>Atlantic coast – 100 km – 350 km into the sea </li></ul></ul><ul><ul><li>Pacific Coast – 10 km – 30 km </li></ul></ul><ul><ul><li>Ocean depth at continental shelf – avg. 200 m </li></ul></ul>
  3. 4. Continental slope <ul><li>Extend from edge of continental shelf to the ocean floor </li></ul><ul><li>Descends from 200 m to 4,000 m deep </li></ul>
  4. 5. Abyssal Plains <ul><li>Sediments constantly settle on the bottom filling in valleys creating flat seafloor called abyssal plains </li></ul><ul><ul><li>Ocean depth at abyssal plain – 4,000 m to 6,000 m </li></ul></ul><ul><li>Seamounts – under-water inactive volcanic peaks </li></ul>
  5. 6. Volcanic Island <ul><li>Volcano that breaches the surface of the water forming an island </li></ul>
  6. 7. Mid-ocean Ridges <ul><li>The area in an ocean basin where new ocean floor has formed </li></ul><ul><ul><li>Forms due to oceanic plates moving apart and lava hardening </li></ul></ul>
  7. 8. Subduction Zones <ul><li>Subduction zones are marked by trenches – long, narrow steep sided depression where one crustal plate sinks beneath another </li></ul><ul><li>Mariana Trench 11 km ( 10,000 m) below sea level (deeper than Mt. Everest is tall) </li></ul>
  8. 9. Seafloor Mineral Resources <ul><li>1 - Continental Shelf </li></ul><ul><ul><li>petroleum and natural gas deposits </li></ul></ul><ul><ul><li>Sand and gravel can be dredged </li></ul></ul><ul><ul><li>Rivers deposit minerals that are concentrated in one place by ocean currents called placer deposit </li></ul></ul>
  9. 10. <ul><li>2 - Deep Water Deposits </li></ul><ul><li>Hot water comes out of cracks near mid-ocean ridges and quickly cools causing minerals to fall out </li></ul><ul><ul><li>Ex: sulfur, iron, copper, silver, zinc </li></ul></ul><ul><li>Hard to mine economically b/c so deep </li></ul><ul><li>How would you mine them? </li></ul>
  10. 11. Section 2 Life in the Ocean
  11. 12. Photosynthesis <ul><li>Using energy from sun to produce energy </li></ul><ul><li>Sun goes through water up to 100 m deep </li></ul>
  12. 13. Producers/Consumers <ul><li>Producers – org. that produce their own food </li></ul><ul><ul><li>ex: algae, seaweed, kelp, phytoplankton </li></ul></ul><ul><li>Algae in oceans are an important source of oxygen </li></ul><ul><li>Consumers – org. that eat (consume) producers </li></ul><ul><ul><li>Ex: shrimp, fish, dolphins, sharks, killer whales </li></ul></ul>
  13. 14. Food Chain/Food Web <ul><li>Org. transfer energy from one to another </li></ul><ul><li>Ex: </li></ul><ul><li>algae copepods herring cod </li></ul><ul><li>seal killer whale </li></ul>
  14. 16. Chemosynthesis <ul><li>Org. such as bacteria that chemosynthesize or use sulfur to create energy </li></ul>
  15. 17. Reproduction <ul><li>Corals and sponges release reproductive cells into water for currents to distribute </li></ul><ul><li>Others like salmon and sea turtle return to the same place each year to spawn or nest </li></ul>
  16. 18. Ocean Life <ul><li>Most org. live above continental shelf since most of food is located here </li></ul><ul><li>b/c relatively shallow & sun passes to the bottom </li></ul>
  17. 19. Plankton <ul><li>Org. that drift with the current </li></ul><ul><ul><li>Ex: algae and jellyfish </li></ul></ul><ul><li>Phytoplankton – producers – plants that drift </li></ul><ul><li>Zooplankton – consumers – hatchlings, crabs, diatoms </li></ul>
  18. 21. Nekton <ul><li>Animals that actively swim </li></ul><ul><ul><li>Ex: fish, whales </li></ul></ul><ul><li>Org. control buoyancy using air bladder </li></ul><ul><li>Bioluminescence – luciferin molecule – used to attract bait, defense mechanism </li></ul>
  19. 22. Benthos <ul><li>Plants/animals living on the seafloor </li></ul><ul><ul><li>Ex: sea cucumber, sea urchins, flounder, sea anemone, sponges </li></ul></ul>
  20. 23. Beach Habitat <ul><li>Sand fleas/mole crabs, worms </li></ul><ul><li>Makes holes in sand when water covers holes they filter feed </li></ul><ul><li>Where sand is constantly covered – fish turtles horseshoe crabs </li></ul><ul><li>Org. deal with lots of change </li></ul>
  21. 24. Rocky Shore Habitat <ul><li>Starfish, anemones, mussels, barnacles, attach to rocks </li></ul><ul><li>Tide pools area where water remains during low tide </li></ul><ul><ul><li>Good place to lay eggs b/c safe from predators </li></ul></ul>
  22. 25. Estuary <ul><li>Area where mouth of a river opens into an ocean, lots of biological life </li></ul><ul><li>Brackish water – fresh water & salt water mix </li></ul><ul><li>Great place for hatchlings – many plants for protective cover and food </li></ul><ul><li>Important economic food source </li></ul><ul><li>Oysters, shrimp, clams, crab </li></ul>
  23. 27. Chesapeake Bay <ul><li>VA’s estuary </li></ul><ul><li>Very easy to pollute b/c rivers flow directly in them </li></ul><ul><li>Pollutants: </li></ul><ul><ul><li>Pesticides, herbicides, insecticides, oil, biosolids, fertilizers </li></ul></ul>
  24. 28. Coral Reefs <ul><li>Coral thrive in sunlit warm water </li></ul><ul><li>Animal build hard calcium capsules around its body </li></ul><ul><ul><li>Calcium from ocean </li></ul></ul><ul><li>Reef forms as org. connect to each other </li></ul><ul><li>Other animals begin to live there </li></ul>
  25. 29. Section 3 Ocean Pollution
  26. 30. Pollution <ul><li>Anything not native to the environment that causes damage to org. by interfering w/ their life processes </li></ul><ul><li>Oceans are environmentally and economically important </li></ul><ul><li>Human activity have consequences for the ocean </li></ul>
  27. 31. Pollution Introduction <ul><li>4 ways: </li></ul><ul><ul><li>Deliberate dumping </li></ul></ul><ul><ul><li>Lost overboard accidentally </li></ul></ul><ul><ul><li>Air pollutants the enter through rain </li></ul></ul><ul><ul><li>Carried by rivers - runoff from lawns (herbicides), crop fields, construction sites (sediment) </li></ul></ul>
  28. 32. Sewage <ul><li>Combined Sewage Overflow – Lynchburg </li></ul><ul><li>Algal blooms – caused by fertilizers, sewage inc. amount of algae, algae dies, bacteria that decompose use up all oxygen, cause fish kills </li></ul>
  29. 33. Chemical Pollutants <ul><li>Pesticides, insecticides, herbicides </li></ul><ul><li>Industrial waste contain heavy metals like mercury and lead, polycarbonated biphenyls (PCBs) </li></ul><ul><li>biological amplification – when harmful chemicals can build up in the tissues of organisms that are at the top of the food chain </li></ul>
  30. 35. Oil <ul><li>Mostly from runoff of streets, parking lots, dumped into drains/ground </li></ul><ul><li>Oil spills – use bacteria that eat oil and change its chemical composition called bioremediation </li></ul>
  31. 36. Solid Waste <ul><li>Balloons, plastic bags sea turtles eat mistaken for jellyfish </li></ul><ul><li>Biohazardous waste – needles can make beaches unsafe </li></ul>
  32. 37. Sediment <ul><li>Forestry, construction, agriculture not practicing good erosion control techniques </li></ul><ul><li>Sediment covers coral reefs & fill estuaries </li></ul>
  33. 38. Bathymetric Maps <ul><li>Isobaths – contour lines used to measure areas of equal depth </li></ul>