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Ocean Properties

Ocean Properties. Ocean Concepts. Buoyancy Temperature Light Density Pressure Depth Sound. Buoyancy. Buoyancy & Isostasy.

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Ocean Properties

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  1. Ocean Properties

  2. Ocean Concepts • Buoyancy • Temperature • Light • Density • Pressure • Depth • Sound

  3. Buoyancy

  4. Buoyancy & Isostasy http://bcs.whfreeman.com/understandingearth/content/cat_110/ch18/earth4e_1817.html?v=category&i=18110.01&s=00110&n=18000&o=%7C00510%7C06000%7C14000%7C17000%7C20000%7C23000%7C22000%7C18000%7C

  5. Archimedes Principle of Buoyancy A floating object displaces a volume of fluid equal in mass to the floating object empty loaded with fish Displaced water

  6. Objects that are more dense than water will sink. • Objects that are less dense than water will float. • Objects that are the same density as water will neither sink nor float. float Neutrally buoyant sink

  7. Organisms adaptation to buoyancy in water • Blubber • Swim bladder • Pneumatophore

  8. Organisms adaptation to buoyancy in water • Air chambers • Large liver & heterocercal tail • Buoyancy Compensator Device (BCD)

  9. Temperature

  10. Isotherms polar 60o temperate 30o 0o tropic 30o temperate 60o polar Lines of equal temperature

  11. Sea Surface Temperature Oct. 2010

  12. Sea Surface Temperature

  13. Sea Surface Temperature 10-24-10 to 10-27-2010

  14. Properties of Light in the Ocean

  15. The Electromagnetic Radiation Spectrum Only green and blue wavelengths pass through water a great distance.

  16. Light Absorption in the Ocean • Light Intensity • decreases with depth • 0-100 m (photic zone) • 100-1000m (dysphotic zone) • >1000 (aphotic zone)

  17. Coral Reef Communities

  18. Hermatypic corals: • possess zooxanthellae • are reef builders Light: Clear water Warm temperature: 18-32oC Low nutrients Low productivity in water • Ahermatypic corals: • no zooxanthellae • rely on tentacular feeding • can live in aphotic zone

  19. Hawaiian Coral Zonation 0 m High light levels Moderate wave energy 6 m Cauliflower coral (Pocillopora meandrina) Moderate light levels Occasional storm wave energy Lobe coral (Porites lobata) 13 m Low light levels Low wave energy Finger coral (Porites compressa) 25 m Very low light, Primarily downwelling No wave energy Plate coral (Porites rus)

  20. Water color and life in the ocean • Ocean color is influenced by: • The amount of turbidity from runoff • The amount of photosynthetic pigment, which corresponds to the amount of productivity • Yellow-green = highly productive water • Found in coastal and upwelling areas (eutrophic) • Clear indigo blue = low productivity water • Found in the tropics and open ocean (oligotrophic)

  21. Light Penetration in the Ocean Wavelength (nm) 400 500 600 700 0 m Photic Zone Photosynthesis 100m No Photosynthesis Dysphotic Zone 1000m Aphotic Zone ~65% of visible light is absorbed in the 1st m

  22. Light Absorption in the Ocean • Spectral Characteristics • red wavelengths absorbed more readily by water than blue wavelengths • blue light penetrates deepest in the oceans

  23. Light effects organisms residing in the photic and aphotic zone. • Phytoplankton productivity • Algae- green, brown, red • Predator/Prey relationships • Diurnal vertical migration • Bioluminescence- luminescent organs on underside mimic downwelling light

  24. Refraction- as light enters the water, it bends; this is due to light traveling through different densities Light entering the ocean is weakened by scattering and absorption.

  25. Density

  26. Density 1 ft 1 ft 1 ft Air 0.08 lbs fw 62.4 lbs sw 64 lbs 1 ft 1 ft 1 ft Piston example: Air is compressible Water is incompressible

  27. 64 lbs Water doesn’t change density under pressure 64 lbs

  28. Ocean Layers • Photic zone: 0-100m • - neustonic layer: 0-1m • Mesopelagic (dysphotic or twilight) zone: 100-1000m • Aphotic zone: bathypelagic zone 1000-4000m • Abyssal and Hadal (trench) zones: 6000m Describe biological and physical characteristics of each depth

  29. Temperature SalinityDensity Low High Low High Low High surface 0 m 100 m 1000 m thermocline halocline pycnocline Thermocline + Halocline = Pycnocline

  30. Thermocline • El Nino • Disruption of thermocline • Upwelling areas • Cool, nutrient-rich deep water is brought to the sunlit surface • Peru fisheries

  31. Thermocline depth Temperature profile

  32. Peru Anchovy Fishery

  33. Peru Anchovy Fishery • Upwelling zone off Peru • Fishery began 1950 • Greatest fish catches for any single species • Fish exported for domestic animal feed • Fishery collapsed due to El Niño and overfishing

  34. Peru Anchovy Fishery = El Niño 1957 1965 1972 1976 1982-83

  35. Peru Anchovy Fishery Normal Year El Niño Year

  36. Sound in Water

  37. Sound in Water Speed of sound- faster in ocean (higher density) 1500 m/sec, which is 4x faster than in air Difficult to determine direction of sound Can hear many things such as ships miles away, shrimp eating, helicopters overhead, and whales communicating. source of noise

  38. Speed of Sound (m/sec) 1,475 1,500 0 1000 2000 3000 4000 high speed min speed sofar layer Depth (m) high speed

  39. SOFAR Channel Distance 0 500 1000 1500 2000 sound rays Depth (m) SOFAR channel

  40. Sofar Layer The depth at which the speed of sound is minimum; Thus, loud noises can be heard for thousands of km Sound generated by Navy test in Indian Ocean at sofar layer was heard as far away as the Oregon coast. May affect behavior and anatomy of marine organisms

  41. Diurnal vertical migration Organisms within the deep scattering layer undertake a daily migration to hide in deep, darker waters during daytime

  42. Deep sea scattering layer: Composite echogram of hydroacoustic data showing a distinct krill scattering layer. Black line represents surface tracking of a blue whale feeding patchiness

  43. Ocean Productivity

  44. Regional productivity • Photosynthetic productivity varies due to: • Amount of sunlight • Availability of nutrients • Thermocline (a layer of rapidly changing temperature) limits nutrient supply • Examine three open ocean regions: • Polar oceans (>60° latitude) • Tropical oceans (<30° latitude) • Temperate oceans (30-60° latitude)

  45. Productivity in tropical, temperate, and polar oceans Zooplankton

  46. Productivity polar oceans

  47. Productivity in tropical oceans

  48. Productivity in temperate oceans

  49. O2 Minimum Zone (OMZ)

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