Oceanography

1. Oceanography • Does water pressure increase of decrease with depth? • Why is the surface temperature of oceans more variable than the water near the ocean floor? • Why will a boat float higher in the Atlantic Ocean than it will in the Potomac River? • What is the average concentration of dissolved salts in 1000 grams of ocean water?

2. Salinity (salt) • 35% is the average concentration of dissolved salts in 1000 grams of ocean water. • When sea water freezes, most the salt is left behind, increasing the density of the remaining seawater. • Salinity tends to be above average in hot areas • Which pair of factors would both cause salinity to increase? • Melting of sea ice and precipitation • Evaporation and freezing of sea water

3. Label the Oceans • Atlantic Ocean • Pacific Ocean • Indian Ocean • Arctic Ocean

5. Facts • Phytoplankton is the base of the marine food chain and the primary energy source of marine ecosystems • The zone in which the ocean temperatures change rapidly is called the? • Mixed layer • Seasonal layer • Thermocline

6. Which of the following statements about ocean pressure is true? • A. Pressure increases with temperature • B. Pressure decreases with depth • C. Pressure increases with depth • D. The pressure is equal throughout the ocean • Why is the surface temperature of oceans more variable than the water near the ocean floor? • E.more energy is exchanged at the surface • F.more animals live near the surface • G.water is less dense at the surface • H.salt concentration is more variable at the surface

7. Which pair of factors would both cause salinity to increase? • A. evaporation and freezing of sea water • B. freezing seawater and precipitation • C. precipitation and melting of sea ice • D. melting of sea ice and evaporation The two most common ions found in ocean water are • E.chloride and sodium • F.potassium and calcium • G.phosphate and nitrate • H.magnesium and sodium

8. When seawater freezes, most of the salt • A.)is included in the ice, increasing its density • B.) is left behind, increasing the density of the remaining seawater • C.) is included in the ice, decreasing its density • D.) is left behind, decreasing the density of the remaining seawater Salinity tends to be above average • e. in areas of high precipitation • f.where large rivers enter the ocean • g.where icebergs are melting • h.in hot areas The base of the marine food chain and the primary energy source for marine ecosystems is • i.zooplankton • j.phytoplankton • k.bacteria • l.salt

9. Questions/Answers • A boat will float higher in the Atlantic Ocean than it will in the Potomac River because ocean water has ? • A lower freezing point • A greater density • Why is the surface temperature of oceans more variable than the water near the ocean floor? • More energy is exchanged at the surface • More animals live near the surface • Which of the following statements about oceans is true? • Pressure increases with temperature • Pressure increases with depth

10. The Water • The two most common ions found in the ocean water are chloride and sodium • Melting of polar ice caps will result in long-term changes in sea levels. • Upwelling is important to ocean life because it brings nutrients to the surface water • Major commercial fishing areas are located in areas of Persistent upwelling

11. Four Oceans Arctic Ocean Pacific Ocean Atlantic Ocean Indian Ocean

12. UPWELLING • Upwelling is important to ocean life because it • A. cools the surface water • B. brings nutrients to the surface water • C. keeps ocean temperature uniform • D. brings carbon dioxide to the surface • Major commercial fishing areas are usually located in areas • e.where density currents form • f.where seawater oxygen levels are high • g.of persistent upwelling • h.that experience frequent turbidity currents

13. Ocean Floor Questions • What is the steepest region of a continental margin? • What is the flattest surface of Earth? • The continental slope is located at the end of the? • What is a cone-shaped undersea mountains of volcanic origin that rises high above the ocean floor called?

14. The continental slope is located at the end of the _____. e. continental shelf f. ocean trench g. shoreline h. rift zone All of the following ocean floor features indicate tectonic activity except v.deep-sea trench w.mid-ocean ridge x.seamount y.abyssal plain • The steepest region of a continental margin is the • A. continental slope • B. continental ridge • C. continental rise • D. continental shelf • The flattest surface of Earth is a(n) • e.island arc • f.guyout • g.seamount • h.abyssal plain

15. Mid-Ocean Ridge • Seafloor rocks near the mid-ocean ridge are older or younger then the rocks far from the mid-ocean ridge??? • Mid ocean ridges are undersea mountain ranges where lithospheric plates are moving apart and new oceanic crust is being formed.

16. Rip Current How should a person escape from a rip current? They should swim parallel to shore to escape the narrow current and let the waves carry you.

17. Convergent Boundaries • Deep-sea trenches occur at convergent plate boundaries where one tectonic plate is sinking beneath another

18. Suppose sound travels at an average rate of 1500 meters per second through seawater above a particular locationHowdeep is the ocean if a sound pulse takes 10 seconds to reach the bottom and return to a surface ship? • 150 meters • 300 meters • 7500 meters • 15000 meters

19. The Marianas Trench in the Pacific Ocean is 36,160 feet below sea level. This deep oceanic trench is caused by: • A.) swift ocean currents eroding away the ocean floor • B.) the collapse of an empty magma chamber in a large volcano • C.) excessive boat traffic disrupting the normal sedimentation process • D.) two tectonic plates colliding and one plunging below the other

20. Barrier islands form off the coast of the land. Where are most barrier beaches found in the U.S.?

21. Currents • What causes a longshore current to form? • Turbidity currents move along the…? • Surface currents in the ocean are primarily cause by?

22. Current Facts • Surface currents flowing away from the equator carry warm water. • The Gulf Stream current affects the weather in Virginia. • The effect of the Earth’s rotation on winds and ocean currents is called the Coriolis Effect. • Deep ocean current are driven by differences in density.

23. Turbidity currents move along the bottom • Surface currents in the ocean are primarily caused by winds. • What causes a longshore current to form? • Waves striking the beach at an angle rather than straight

24. More about currents • Deep ocean currents are driven by: A.) tidal forces B.) differences in density C.) differences in oxygen content D.) changes in conveyor belt circulation • Which of the following is not a cause of ocean currents? A.) wind B.) gravity C.) variation in water density D.) type of seal life

25. Surface Currents • Surface currents flowing away from the equator carry _____ water. In the northern hemisphere, surface currents tend to flow ________. Surface currents in the ocean are most commonly driven by ________. -clockwise, warm, wind

26. Sun, Moon, and Earth • Tides are highest when Earth is in line with both the sun and moon. • When the Earth, sun, and moon are at 90 degree angles to each other, the tidal range is ______ • When the Earth, moon, and sun are lined up, what type of tide occurs?

27. Tide Facts and Terms • What is most responsible for tides? • What is the difference between the high and low tide water levels called?

28. Waves • The lowest point of a wave is called the trough. • As a wave moves in shore and grows in height it will eventually topple over, forming a breaker. • What causes the top of a wave to fall forward when it moves in shore? Friction with the bottom • The distance from crest to crest or trough to trough in a wave is the wavelength. Tsunami is a wave that would have a very long wavelength.

29. Waves • Which of the following waves can have a very long wavelength? A.) rip current B.) tsunami C.) surface current D.) upwelling current

30. You Answer • The lowest point of a wave is called the a.) crest b.) height c.) trough d.) tide As a wave moves in shore and grows in height it will eventually topple over, forming a a.) mess b.) tide c.) breaker d.) current

31. What causes the top of a wave to fall forward when it moves to shore? a.) friction with the bottom b.) storm surges c.) upwelling currents d.) wind