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2013-04-01 10:55:44

Exam 2
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  1. When is water at it's greatest density?
    When it is a liquid -> pure fresh water is 1g/cm3 at 3.98 degrees C (maximum density)

    Remember that ice cubes float
  2. How does salt effect the freezing point of H20?
    The freezing point is lowered (sea water freezes at -2 dC) and boiling point is raised.
  3. Will adding heat to water increase or decrease density?
    Decreases: Molecules come apart, and take up more volume, which lowers the denominator and therefore decreases density.
  4. On average, to what depth does light penetrate the ocean?
    No light below one thousand meters and only 1% of light left after 150 meters.
  5. Does light penetrate the ocean more in coastal zone or in the open ocean?
    The open ocean -> it is less clouded by sand, silt, and sediment getting churned up
  6. Why are many salts easily dissolved in H2O?
    Because of it's polar nature -> water is a posative and salt is a negative and therefore they attract one another
  7. Average salinity of the ocean?
    35 parts per 1000
  8. Explain salt balance
    It is the process that adds and removes salt from the ocean. (Main way is adsorption)

    • Inputs: Rivers
    • Outputs: Sediments and Evaporites

    Adsorption = adherence of ions and molecules onto a particle’s surface
  9. What are the three nutrients in the ocean?
    Nitrogen, phosphorous, and silicon

    Source: Rivers & run off
  10. When are nutrient levels at their lowest? Why?
    When population is at it's highest because primary producers take up the nutrients, when they die and decompose, the nutrients return
  11. Know how photosynthesis in the ocean controls the distribution of O2 & C02 within the ocean.
    Photosynthesis uses CO2 within the ocean. Photosynthesis uses CO2 to create energy (carbohydrates) and a bi-product is O2

    • Photosynthesis removes CO2 and produces O2 at the surface
    • – Respiration produces CO2 and removes O2 at all depths
    • – Compensation depth (Photosynthesis = Respiration)
  12. what is decomposition?
    Bacterial breakdown of nonliving organic material.

    Requires O2 and CO2 is the bi-product.
  13. What buffers the ph of the water in the ocean?

    Water has a pH balance of 7 and CO2 helps prevent sudden or very large charges in the acidity or alkalinity of a solution

    It adds or removes hydrogen

    Sources of CO2: directly from the atmosphere, respirationof marine organisms, oxidation of organic matter
  14. Why is maintaining a relatively constant pH in the ocean important?
    It's important for animals with a shell that reequire constant pH

    Also for the chemisty of the sea water (in part controlled by it's pH (CO2 controls the pH of seawater)
  15. What is the initial source of energy to the Earth?
    Solar radiation: can be absorbed, reflected, and re-radiated
  16. Know why and how the distribution of solar energy to the Earth
    Differences in the Earth's Axis

    • Solar Radiation Varies:
    • • Latitude
    • • Distance between Earth and Sun
    • • Time of Day

    • Distribution of solar radiation
    • – Obliqueness of incident solar radiation
    • – Latitudinal variation
    • – Greatest amount received - (23.5 N to 23.5 S)
    • – Higher latitudes solar radiation has to travel throughmore atmosphere
    • - Therefore more energy is absorbed
  17. How is the atmosphere heated?
    Through the sun and from below when heat is put in from the Earth
  18. Explain the heat budget.
    • – Solar input must balance solar output
    • – Average Earth Temperature is 16oC
    • – Solar Energy is reradiated from the surface as along wave.
    • – Surface of Earth (including oceans) is heatedfrom above
    • – Atmosphere is heated from below

    • Heat budget
    • – Heat gained at Equatorial latitudes (surplus)
    • – Heat lost at higher latitudes (deficit)
    • – inequality sets the atmosphere and oceanscurrents in motion
    • – Winds and ocean currents redistribute heataround the Earth
  19. How is heat received and redistributed?
    Wind and ocean currents redistribute heat
  20. Why is there greater variation (during the year) in the amount of solar radiation received at the poles than the equator?
    All the snow is very reflective along with the fact that the Earth's angle is on the axis. Also, the position of the earth in relation to the sun, the equator is always closer where the poles vary much more
  21. How does heat capacity of water differ from land?
    Land heats up and cools quicker, the ocean takes longer to heat up but holds on <-larger temp variation on land
  22. Does this difference in heat capacity from land to water affect the seasonal temps in the N. Hemisphere?
    Warm water flows higher and cold water flows lower during the summer.

    The S. Hemisphere is effected by the ocean, where the Northern Hemisphere is effected by land.
  23. How is solar radiation trapped in the atmosphere?
    The greenhouse gas effect, radiation gets trapped
  24. Explain seasonal variation of CO2 in the atmosphere? Why does it occur?
    There is less CO2 when plants are photosynthesizing and stops (decreases) during the winter -> the lowest CO2 concentration is in late spring, summer and fall

    respiration continues to produce CO2 all year long.
  25. How and why does air move?
    Think about change in density

    Air movies due to differing pressures and cold fronts coming from the N. and S. and moves from areas of high pressure to low pressure
  26. Seasonal Changes Def:
    during the summer in the N. hemisphere we have a low pressure zone
  27. Monsoon Effect Def:
    the Tibetan plateau releases a high pressure, hot winds that come from the sea in the summer and brings a huge amount of rain during the summer, during the winter the exact opposite happens.
  28. Topographic effect def:
    Mountains deflect wind upward, rising air on windward side of mountain cools; heavy precipitation, descending air on leeward side; low precipitation
  29. Land sea breeze def:
    a switch in high and low pressure zones
  30. El Nino def:
    Southern isolation, occurs every 3-7 years -> compelled interaction between oceans and atm in the tropical Pacific

    • - collapse of southeast trade winds
    •   -> surface warm pool in Western Pacific moves eastward, upwelling shuts down off the west coast of S. America

    • Global Effect:
    • -unusually dry periods in some regions
    • -higher than normal rainfall in other regions
    • -fishing industry
  31. How does a hurricane form?
    Energy forms in a low pressure zone, bringing with it water vapor (warm water for the ocean). It starts as a tropical depression in Africa, and as it travels over warm water it changes levels, critical sea surface temperature of 27oC along with increased evaporation rate = more energy. Energy released through condensation.
  32. What is, and what causes a storm surge?
    Associated with a big storm, low pressure zone water level rises, less water pressure, wind pushes water toward the coast.
  33. Why is the ocean layered?
    Changes in temperature and salinity
  34. How does the seasonal change at the N. Pole effect the salinity of the Arctic Ocean?
    When sea ice forms, it removes water from the ocean and increases salinity and therefore density as well, in the summer it melts and adds water, decreasing the density and salinity
  35. Thermocline def:
    zone of rapid temperature change with depth of (100-1000 m)

    • Thermo: Temperature
    • Cline: Change
  36. halocline def:
    zone of rapid salinity change with depth of (100 to 1000 m)

    • Salty halo
    • Cline: Change
  37. Thermocline circulation:
    vertical density driven circulation resulting from change in temperature and salinity.

    More dense water forming over less dense water, unstable and must change

    -brings nutrients to the surface and oxygen to the depths and happens off the coast of RI due to seasonal changes

    • Turned and Overturned (good thing) - more dense water sinks and less dense water rises
    • -Summer: stable column (surface warming)
    • -Fall: Cooling: Overturned, deepening mix layer
    • -Winter: continues to overturn, storms, erases shallow thermocline
    • -spring: warming, layered structure, shallow thermocline re-established
  38. What happens at zones of convergence and divergence in the oceans? Why is each important?
    Convergence: downwelling - low in nutrience and primary producers - formed when surface waters are driven together by the wind or against a coast; water sinks and brings O2 rich surface water to greater depth

    Divergence: upwelling - high in nutrients and primary producers - formed when wind blows surface waters away from an area or coast , cool nutrient rich bottom water rises to the surface, example: off the coast of S. America
  39. Why does the Pacific Ocean lack a northern down welling current?
    It is isolated from the Arctic Ocean, where down welling comes from.
  40. Explain Ekman Spiral:
    the reflection of the surface currents in a spiral formation (will move 45* with respect to the surface direction, starts out at 45* then  on the surface then continues down until it is at a 90* angle
  41. Keman Transport:
    when the surface current is at 90* to the current

    -deflection is to the right in the N. Hemisphere, left in the S. hemisphere
  42. What are ocean gyres and how do they form?
    Ekman transport;

    -rotational movement of the water in the n. & s. Pacific & Atlantic, clockwise in the N. Hemi, centered around 30* latitude ; permanence (westerly and trade winds)

    Big circle currents
  43. How do ocean eddies form?
    Fast moving currents move into slower moving water; currents develop meanders that can break off to form eddies

    eddies: a pocket of water moving in a circular migration that eventually break off

    It takes less than a tidal cycle to form (less than a day) but can last all along the Atlantic.

    Little circles