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The Oceans

The Oceans. An overview. A quick oceans tour. Marine ecosystems. Cover 70% of the Earth’s surface. List as many different marine ecosystems as you can. Estuaries: fresh water from river mixes with ocean Rich in nutrients Wetlands form in shallow areas. Marine ecosystems: Estuaries.

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The Oceans

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  1. The Oceans An overview

  2. A quick oceans tour

  3. Marine ecosystems • Cover 70% of the Earth’s surface. • List as many different marine ecosystems as you can.

  4. Estuaries: fresh water from river mixes with ocean Rich in nutrients Wetlands form in shallow areas Marine ecosystems: Estuaries

  5. Salt marsh Estuaries: very productive ecosystems What does that mean? Make lots of biomass Lots of plant growth/m2 Nurseries for fish, crustaceans Estuaries

  6. Estuaries • Coastal • Partly enclosed • One or more rivers flow into them • Water is brackish—ranges from fresher upstream to saltier where estuary grades into the ocean.

  7. Klamath River estuary

  8. Value Aquatic nurseries Protected harbors Fishing, other recreation Habitat for non-aquatic animals, such as bald eagles, shorebirds Threats Many near populated areas May be filled Pollutants Sewage Runoff from rivers Estuaries

  9. Florida salt marsh Tidal creek running through it Whole region is tidal, meaning affected by the daily tides Intertidal zone

  10. Means: ``region between the tides’’ Constant change Intertidal zone

  11. Intertidal Zone

  12. Marine ecosystems: mangrove swamps • Coastal areas • Mangrove trees grow partly submerged • Protect coasts from erosion, especially during storms • Tsunami of ‘04

  13. Mangrove swamp • Roots hold sediment • Habitat for thousands of animal species, such as shrimp • In South America and Southeast Asia, mangrove swamps being cleared for shrimp farms

  14. Coral reefs

  15. Coral reefs • Made of animals = coral polyps • Limestone skeletons form the reefs • Thousands of species of fish, plants live among the corals  biodiversity hotspot • Need light for photosynthesis, water within temperature and salinity range • BUT: in trouble • People • Warming oceans

  16. Coral reefs • Individual corals are polyps • Grow together to form large colonies • BUT: grow very slowly, inch or so a year

  17. corals • ANIMALS • Individual = polyp • Colonies, like reefs, may have been in existence for thousands of years • Most corals contain an algae, zooxanthellae  symbiotic

  18. Coral reef distribution

  19. Fishing for tropical fish on coral reefs, using explosives. • For pet stores and for restaurants • Philippines • Also use cyanide • Small amounts stun fish, but continued use can kill coral

  20. Continental shelf • aqua color

  21. Continental shelves • Extension of the continents • Shallow (average about 460 ft) • Significance? • Light reaches much of the shelf • Teaming with life—many important fisheries

  22. Littoral zone • Nearest the coast • From high water mark to shallow, submerged areas

  23. Pelagic – water • Benthic – bottom • Abyssal – deep • Photic – affected by light

  24. Marine ecosystems • Open ocean: Pelagic • Fish • Marine mammals • Plankton • Light at surface

  25. Marine ecosystems • Deep Ocean: benthic zone • Very cold—light doesn’t penetrate • Few if any plants • Bottom feeding organisms • Starfish, anemones, sponges

  26. Marine ecosystems • Deepest reaches of the ocean: Abyssal zone • Cold • Dark • High pressure • In some places: hydrothermal vents spew superheated water

  27. Ocean circulation • Ocean conveyor

  28. OCEANS How they work How we protect them

  29. Oceanography • Study of the physical ocean • Cover 71% of the Earth • Contains 97 % of its surface water

  30. Ocean water • 96.5 % H2O by mass • Remainder: various salts • Temperature: • Warmer near the surface • Deep water (below ~1000 m) is equally cold • Density: • Colder, saltier water is denser = deep water

  31. Salinity patterns

  32. Ocean currents • Water flows horizontally • Causes? • Surface: wind • Deep: density differences – salinity, temperature • ocean conveyor

  33. Vertical movements • Upwelling • Deep, cold water rises to replace surface waters that flow away • Brings nutrients to surface • Site of rich fisheries

  34. Marine ecosystems • Biological diversitydiversity_over_time.pdf

  35. Coral reefs form in nutrient poor waters • Nutrients tied up in living things • Nutrients tightly recycled

  36. Coral Bleaching • Corals expel the single-celled algae normally living in their tissues • Related to global warming

  37. Episodes of coral bleaching

  38. Marine ecosystems

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