1. Bell Ringer Name the ocean-mapping technology.
Maps as it orbits the Earth
Maps from a ship using sound waves
Maps by diving deep in the ocean
Topex/Poseidon
SONAR
submersibles

2. Saltwater Properties

3. Ocean Water Nutrients Dissolved minerals Dissolved gases
Oceans contain 97.5% of water found on Earth (saltwater)
What else is in ocean water?
Nutrients
Dissolved minerals
Dissolved gases
Microscopic life forms
All of these combined make the ocean a thriving ecosystem for the organisms that live there

4. Ocean Water
The Arctic and Antarctic Oceans are covered by sea ice

5. Ocean Water
Icebergs – large masses of ice formed when ice crystals build on each other

6. Ocean Water
As the Earth’s global temperatures continue to increase, sea ice is melting, changing the saltiness of the water as well as the sea levels
Sea Level – the average level for the surface of Earth’s oceans
Serves as a reference for elevation (ex: Raleigh is 315 feet above sea level)

7. Ocean Water
As sea levels rise, coastlines around the world will change as low-lying land is covered in water

8. Ice floats because it is less dense than water
Ocean Water
Density = mass / volume
Things that are denser [rise above / sink below] things that are less dense.
Sea ice floats, so it is [more / less] dense than water
Ice floats because it is less dense than water

9. Ocean Water
The density of ocean water depends on two things: salinity and temperature

10. Salinity
Seawater is a solution of about 96.5% water and 3.5% dissolved salts
The most abundant salt in sea water is sodium chloride (NaCl, table salt)

11. Salinity Salinity – the amount of dissolved salts in seawater
Salt adds weight (mass) to water, so saltwater is denser than freshwater

12. Salinity Adding salt to water lowers its freezing point
So the higher the salinity, the colder the water can be and still be a liquid
This is why we put salt on roads in winter to prevent them from freezing

13. Salinity The average ocean salinity is 35 ppt (parts per thousand)
Salinity stays relatively constant in the ocean because sea salts are removed at the same rate they are added

14. Salinity How are salts removed from ocean water?
Marine organisms remove salt from the water to build their shells, bones, and teeth
Salts can precipitate from (drop to the bottom of) seawater in dry and coastal regions

15. Salinity
Salinity is controlled by a balance between freshwater removed by evaporation and added by rivers and rain
Evaporation:
removes freshwater, leaving salt behind
Precipitation:
adds additional freshwater

16. Salinity
____ Salinity – places with lots of evaporation but little precipitation
Example: Mediterranean Sea in Europe (>38ppt)
It is nearly closed off from the ocean and there is more evaporation than rain/freshwater
High

17. Salinity
Low
_____ Salinity – places with lots of rain that dilutes the water

18. Salinity
Low
_____ Salinity – places where freshwater streams empty into the ocean (___________)
Example: Baltic Sea in Europe (10 ppt)
It’s nearly closed off from the ocean and has hundreds of rivers that empty into it
estuaries

19. Salinity ____ Salinity – polar regions near melting ice caps
Example: Arctic Ocean (30 ppt)
Low

20. Temperatures Average ocean temperature is 15oC (59oF)
Equatorial waters are warmest, averaging 30oC
Polar waters are coldest, averaging -2oC
Freshwater freezes at ___oC.
So how is the water still liquid?
Remember, saltwater freezes at a lower temperature than freshwater

21. Temperatures
Density is temperature-dependent, so ocean temperatures also vary based on depth
Cold water – dense
Warm water – less dense
Cold water sinks to the lower parts of the ocean while warm water remains near the surface
Review: Convection: warm material _______ and cold material _______!
rises
sinks

22. Temperatures The ocean is divided into three temperature-based layers:
Surface Layer
Thermocline
Deep Water

23. Temperatures Surface layer – 100m thick, relatively warm water
Only layer lit by the Sun; the rest of the ocean is very dark!
Nearly 90% of all ocean organisms live in the surface layer
Surface Layer

24. Temperatures
Thermocline - rapid decline in temperature with depth (thermo = temperature, cline  decline)
Surface layer

25. Temperatures
Deep water –dark (nearly pitch-black) and cold (very close to freezing)
Surface layer

26. Temperatures Relatively few organisms live in the deep
Those that do are some of the most unique organisms on Earth, adapted to live in the cold and dark

27. Temperatures
Hydrothermal vents – openings in the seafloor which erupt with magma-heated fluids
Typically located along the mid-ocean ridges

28. Temperatures Water can reach 750°F!
Lots of organisms in comparison to the rest of the deep water
These organisms are specially adapted to survive the hot temperatures and chemicals that come out of the vents
Example: Giant Tube Worms

29. Salinity and Temperature
Salinity: Salt water is [more / less] dense than freshwater. Therefore, salt water would [rise above / sink below] fresh water.
Temperature: Cold water is [more / less] dense than warm water. Therefore, cold water would [rise above / sink below] warm water.
Question: Which of the four types of water would float above all the others?
A. warm, salty
B. warm, fresh
C. cold, salty
D. cold, fresh

32. Get out a sheet of notebook paper
Adaptation – inherited characteristics (characteristics you are born with) that help an organism survive its environment
Example: Where does a polar bear live?
What are some characteristics that help it live there?

33. How would you describe deep ocean water?
Warm or cold?
Sunny or dark?
Deep sea creatures have to adapt to live in this environment. We’re going to watch a video about deep sea creatures. As you are watching, write down 5 specific (different from each other) adaptations these creatures have developed that enables them to live in the deep ocean water.
No phones, sleeping, or work from other classes. No cheating! If your tablemate chooses to be off-task during the video while you pay attention, don’t let them copy your paper! Turn in after video.