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The Water Planet Ch. 22

The Water Planet Ch. 22. What is Oceanography?. the study of the Earth’s oceans using chemistry, biology, geology, and physics. Oceans cover 70% of the Earth’s surface. Ocean Research 22.1. The use of submarines in World War II advanced ocean research with the invention of SONAR.

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The Water Planet Ch. 22

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  1. The Water PlanetCh. 22

  2. What is Oceanography? the study of the Earth’s oceans using chemistry, biology, geology, and physics. Oceans cover 70% of the Earth’s surface

  3. Ocean Research 22.1 The use of submarines in World War II advanced ocean research with the invention of SONAR.

  4. H.M.S Challenger • 1872 first large-scale ocean research project • Measured: • Temperature • Depth • Took water samples • Observed currents

  5. World War II • Better ocean maps and charts • Instruments: • Sonar • Magnetic recorders

  6. Modern Research (Technology) Deep sea-corers take sediment samples Sonar measures ocean depth Deep sea cameras and lights, robotics, and advanced technology help explore the sea floor & take samples buoys & satellites radio data back SST, sea level, & mov’mt

  7. Think-Pair-Share: How do humans effect the oceans? List your ideas in your notes!!

  8. Human Effects • Oil spills • Deep sea mining • Magnesium (Mg) • Table salt • Pollution • Dredging • Disturbs ocean floor • Global warming • Melts ice caps, changes salinity & sea level

  9. Special Properties of Water 22.2 The density of water is greater than its solid form, ice

  10. Density • Density= mass ÷ volume (g/cm³)- it’s a ratio! • Density of fresh water= 1.0 g/cm³ (above freezing) • Density of ice= 0.92 g/cm³ • Water expands as it freezes because of it’s shape! • ICE FLOATS!!!

  11. Aqueous Solutions • ocean is best example! • as salt increases, density increases • change water’s: • pH • density • boiling & freezing points

  12. Ocean Water 22.3 Salinity and temperature are two characteristics of water masses that help scientists study oceans and their behavior.

  13. Composition of Seawater • Contains salts as dissolved ions • 85% sodium chloride ions • more than 70 elements • some elements, such as calcium (Ca)--needed for marine life shells

  14. Salinity measure of dissolved salts in water units= parts per thousand (‰) Ex: 1000 grams of seawater contains 35 grams of salt= 35 ‰ measured w/ hydrometer

  15. Salinity • oceanographers calculate salinity by electrical conductivity of seawater • The higher the salinity, the stronger the electrical current • units= practical salinity units or psu • average seawater = 35 psu

  16. Variations in Salinity LOW SALINITY AREAS HIGH SALINITY AREAS * SALINITY IS USUALLY AVERAGE (35‰) NEAR THE BOTTOM near rivers where fresh water enters high precipitation near equators sea ice melts • hot, dry climates w/ high evaporation rates • about 30º N & S (deserts) • near poles as water freezes

  17. High-5 & Share: What do you think the salinity of the ocean is like at the Equator? Why?!

  18. High-5 & Share: What do you think the salinity of the ocean is like at the Poles? Why?!

  19. At your seat… Complete the bottom of p. 6 in your INB. Make a key for high or low salinity and use 2 colored pencils. Ask for help if you need it!

  20. Salt Enters & Leaves the Ocean ENTER LEAVE * Scientists believe the salinity of the ocean hasn’t changed in over 200 million years! underwater volcanoes erosion from rocks marine organisms decompose marine organisms use minerals for life precipitate out of solution into sediment at floor

  21. Temperature of the Ocean • heat from sun • temperature decreases w/ depth • Ocean divided into 3 temperature zones: • Mixed Layer or Epipelagic Zone • Thermocline • Deep zone

  22. Epipelagic Zone or ‘Mixed Layer’ • winds and currents mix heat evenly • most life lives here; only zone for plants • makes up 2% of ocean’s volume • can be 50-100m deep; in some spots 300m • temperature depends on latitude and season; poles and equator mixed layer temperature is constant • Most oxygen- b/c of atmosphere & organisms (photosynthesis) • Oxygen decreases with depth

  23. Creation of the Mixed Layer (surface)

  24. Thermocline Page 8 INB: • Which one belongs to the poles? The Equator? The mid-latitudes? • Talk with your neighbors!!! Temperature decreases rapidly throughout this zone Little to no light Varies most at mid-latitudes, not much variation at poles or Equator

  25. Deep Zone No sunlight reaches seafloor- DARK! Very little oxygen & life Polar water masses are found at bottom because they are denser than other water and move around globe Seafloor temperature @ bottom = ~ 2° C

  26. Water Mass • Characterized based on where they originate • Body of water characterized by: • Salinity • temperature

  27. What do YOU think?? How do water masses layer in the ocean? Why?

  28. Ocean Life 22.4 Scientists estimate that the oceans harbor as many as 10 million species! Life forms range from microscopic organisms to the largest known animal, the blue whale.

  29. Photosynthesis in the Ocean • takes place within mixed layer • Phytoplankton: microscopic single celled protists that float freely within ocean waters • take CO2 out of water and replace with oxygen • basis of food chain in ocean • Diatoms are examples with silica shells; deposited on seafloor when they die • Blooms- abundant phytoplankton populations; change color of seawater to green, yellow, or brown • Visible from space; scientists use to locate groups of life forms

  30. Blooms are visible from space and help scientists track life forms. Phytoplankton

  31. Marine Animal Life • Zooplankton: microscopic animals that eat phytoplankton or smaller zooplankton • other animals eat zooplankton • can be larvae of larger animals s.a. squid, crab, jellyfish • moderate salinity by absorbing ions to make shells; back into water when they die • promote nutrient circulation as waste falls to bottom • Coral: tiny sea creatures that form reefs • lime from ocean creates shells; when they die new ones grow on old ones • prevent beach erosion b/c they stop waves along coasts • provide nutrients and shelter for larger organisms

  32. Marine Animal Life (cont.) • Nektons: free-swimming organisms • include fish, whales, jellyfish • survival depends on temperature, salinity, and nutrient circulation • important food supply for other nektons and humans • overfishing, pollution, and trawling destroy populations & ecosystems

  33. Deep Ocean Life • no photosynthesis means no oxygen so CO2 accumulates • Hydrogen sulfide is primary source of energy • spewed out of deep sea vents and smokers • bacteria use chemosynthesis to produce food here • chemosynthetic bacteria are food for larger organisms • larger organisms thrive because of food & heat

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