1. Bellwork 2/2 What causes surface circulation?
How is surface circulation in the Southern Hemisphere different from the Northern Hemisphere?
How do gyres play a role in the creation of the Great Pacific Garbage Patch?

2. Gyres & The GPGP
Circular moving ocean currents trap material within the North Pacific basin.

3. Sometimes, the material is not confined to one basin.
This simulation stops at 10 years…plastic & other materials don’t “go away” after 10 years

4. Which currents are easier to observe on the real data?
Why might the Canary Current be more difficult to observe?

5. 2. Deep Ocean Circulation
accounts for thorough mixing of deep water masses
formed by differences in salinity & temperature
“thermohaline” currents
Begin forming in high latitudes as cold, salty water sinks

7. So, what causes these Thermohaline Currents?
As the name suggests…differences in water Temperature & Salinity (salt content)
Let’s take a closer look at the composition of this ocean water…

8. Composition of Seawater
What is in Seawater?
Salt!
Sodium Chloride (NaCl)
But also…magnesium, sulfate, calcium, and potassium

9. Salinity Total amount of solid material dissolved in water
Expressed in “parts per thousand” (ppt)
Is the salinity of our oceans equal throughout?
What might contribute to this?

10. Temperature: Ocean water is not the same temperature throughout…
Latitude affects surface water temperatures

11. We’re going to investigate in our lab today 
Density:
The density of our seawater is also not equal throughout each basin!
WHY??? WHO CARES???
We’re going to investigate in our lab today 

12. Quick review…Density:
What is meant by “Density”?
How much matter is in a given volume
D= m/v
Less dense material floats on top of more dense material

13. Ocean Water Density Lab:
How does temperature & salinity affect ocean water density?
How does this lead to layering & deep currents in the ocean?

14. Bellwork 1/30
In Part 1 of your lab…what happened to the blue (cold) water melting off the ice cube when it was in warm water? What about cold water? What sorts of observations did you make?

15. Ocean Water Density Lab:
How does temperature & salinity affect ocean water density?
How does this lead to layering in the ocean?

16. Part 2: Salinity & Density
You are trying to observe how the fresh, slightly salty, and very salty water layers
You do not need to stir the different waters together…just gently pipet a few drops into the beaker

17. Bellwork 2/1 Please, turn in your Ocean Water Density lab…if you haven’t already 
1. What sorts of factors can change ocean water density? 2. How might ocean water density play a role in ocean currents?

18. Coming up… Monday 2/13: Today 2/1: Friday 2/3: Tuesday 2/7:
Finish ocean water properties (density)
Intro to Sediments
Begin sediment lab
Friday 2/3:
Finish sediment lab
Discuss ocean sediments
Tuesday 2/7:
Ocean Acidification
Thursday 2/9:
Wrap up loose ends
Review time
Monday 2/13:
-- Unit 1 Oceans Test…and begin Unit 2: The Atmosphere!

19. Sources of Sea Salts
Chemical weathering of rocks
Volcanic eruptions

20. Relative proportions of water and dissolved components in seawater

21. The ocean’s salinity has been relatively stable for millions of years
So, if these salts are constantly being put into the ocean, is the water getting saltier?!
Nope!
The ocean’s salinity has been relatively stable for millions of years
Why not?
Organisms using the salts
Salts are chemically precipitated out as sediments

22. Processes affecting seawater salinity
Processes that decrease salinity (add water)
Precipitation
Runoff from land
Icebergs melting
Sea ice melting
Processes that increase salinity (remove water)
Evaporation
Formation of sea ice

23. Variations in the ocean’s surface temperature and salinity with latitude
What’s going on here?

24. Change in salinity = halocline

25. Temperature vs. Depth Density vs. Depth

26. Ocean temperature Temperature variation with depth Low-latitudes
High temperature at the surface
Rapid decrease in temperature with depth (thermocline)
High-latitudes
Cooler surface temperatures
No rapid change in temperature with depth

27. Variations in ocean water temperature with depth

28. Ocean density
Density is mass per unit volume - how heavy something is for its size
Determines the water’s vertical position in the ocean
Creating layers in the ocean
Factors affecting seawater density
Salinity
Temperature
Which has a greater influence—temperature or salinity?

29. Ocean density Density variations with depth Low-latitudes
Low density at the surface
Density increases rapidly with depth (pycnocline) because of colder water
High-latitudes
High-density (cold) water at the surface
Little change in density with depth

30. Variations in ocean water density with depth

31. Quick Practice
Draw graph of Temperature VS Depth at: Hawaii

32. Draw graph of Temperature VS Depth at: Bering Strait

33. Draw graph of Density VS Depth at: New Zealand

34. Draw graph of Density VS Depth at: Varangerhalvoya National Park (Botsfjord, Norway)

35. Why does any of this matter?!?!
Ocean Currents Weather Climate