1. Earth’s Oceans

2. Freshwater vs. Seawater (differences)
3% of Earth’s water
2% in glaciers
1% lakes, rivers, & aquifers
Mixture of substances not just pure H2O
Minerals from rocks and pollutants from air get mixed in
Density = 1.0g/cm3
Freezes at 0ºC
97% of Earth’s water
Mixture of substances
96.5% water and 3.5% dissolved salts
NaCl is most abundant salt
Dissolved gases include O, N, CO2
Salinity varies from place to place
Density = g/cm3
Freezes at -2ºC

3. Both Fresh and Seawater
Respond to solar radiation (sunlight)
Remember, the sun drives the water cycle

4. Visible Light Visible light is both absorbed and reflected
Most wavelengths are absorbed
Blue light is reflected
All wavelengths are absorbed by 100m depth so deep lakes and oceans are dark except for surface

5. Absorption of Light
Water absorbs light, which gives rise to another physical property of oceans—they are dark
In general, light penetrates only the upper 100 m of seawater
Light sufficient for photosynthesis exists only in the top 100 m of the ocean

6. Infrared Rays Determine water temperature
Rapidly moving water does not have time to absorb infrared rays
Lakes and ponds become warm because they absorb infrared rays
Upper zone of ocean absorbs infrared rays so only surface is heated
Surface temperature varies with latitude
Deep seawater is very cold (Don’t draw diagram until the end)

7. How Did the Oceans Form?
About 4.5 billion years ago, there were no oceans
Sometime before 4 billion years ago, water vapor in the atmosphere condensed and fell as rain
The rain filled the deeper levels of Earth’s surface and the first oceans began to form

8. The Global Ocean
3/21/2011
All waterways on earth are connected to the oceans because almost all watersheds empty into the ocean
Minerals & gases are carried along with the water and dissolve into seawater

9. The Global Ocean The ocean affects every person on Earth
3/21/2011
The Global Ocean
Oceans produce most of the earth’s rain and oxygen (over 50%)
The ocean affects every person on Earth

10. Divisions of the Global Ocean
3/21/2011
Pacific Ocean - largest (North and South)
Atlantic Ocean - half the volume of Pacific (North and South)
Indian Ocean - 3rd largest
Southern Ocean - newest recognized in 2000
Arctic Ocean - smallest with most covered in ice

11. Divisions of Ocean
All five of Earth’s oceans are connected to each other by the ocean currents creating 1 global ocean

12. Ocean water contains salt
Ocean water is 96.5% water
Plus, ions of dissolved salts
Evaporation removes pure water
Leaving salt behind
Low levels of nutrients (nitrogen and phosphorus)
Oxygen is added by plants, bacteria, and atmospheric diffusion

13. Ocean water is vertically structured
Temperature declines with depth
Heavier (colder, saltier) water sinks
Light (warmer, less salty) water stays near the surface
Temperatures are more stable than land temperatures
Water has high heat capacity (heat required to increase temperature by a given amount)
It takes more energy to warm water than air
Oceans regulate Earth’s climate
They absorb and release heat
The ocean’s surface circulation moves heat around

14. What’s in Ocean Water? Oceans contain many dissolved solids and gases
Dissolved solids like minerals and salts are eroded from the land as rivers travel to the sea
When the water evaporates, these minerals are left behind; This is why the ocean is salty
Some gases become dissolved in the ocean through wave action; Others come from photosynthesis and respiration of ocean organisms

15. Characteristics of Ocean Water
Dissolved solids: Sodium chloride, or table salt, is the most abundant dissolved solid in the ocean. Other solids are also found in ocean water. (Draw next slide)

17. Salinity Amount of dissolved salts present in a sample of ocean water
Described in parts per thousand
‰ is the notation for parts per thousand
Changes in Salinity - Climate and water movement affect salinity; Coastal water, in cool, humid places, has low salinity; Slow-moving bodies of water have higher salinity than other parts of the ocean do
Salinity in various regions all differ
Range from 33‰ to 40‰
Average Salinity is 35‰
Salinity-generally increases with depth (WRITE THIS IN!)

18. Characteristics of Ocean Water
Dissolved Gases Nitrogen, oxygen, and carbon dioxide are the main gases dissolved in ocean water
More than half of Earth’s oxygen comes from the surface layers of the ocean
About 93% of the world’s carbon dioxide is dissolved in the ocean

19. CO2 Has more than 60 times that is the atmosphere
Called carbon sink (can trap CO2 for thousands of years); *copy the next graph

21. Behavior of Gases in Water
You know that warm water dissolves solids more easily than cold water
Try to dissolve sugar in cold and warm water, and you’ll see that it’s true
Gases behave in the opposite way; Cold water dissolves gases more easily than warm water
Open a warm and a cold soda; The warm one will fizz more and go flat more quickly
This is because the CO2 dissolved in the soda stays dissolved easier in cold water

22. Behavior of Gases in Water
Pressure also plays a role in how easily gases dissolve in water
If the water is under high pressure, gases dissolve more easily than water under no pressure
To keep CO2 dissolved in soda, it is bottled under pressure; When you open the soda, it loses pressure; The CO2 fizzes out and the soda eventually goes flat

23. Temperature Zones (Draw in box!)
3/21/2011
25°C Surface 0m
23°C Surface Zone m
5°C Thermocline m
1°C Deep Zone to1200m

24. Temperature Zones Sunlight heats the top 100m of the surface zone
3/21/2011
Sunlight heats the top 100m of the surface zone
Surface currents mix the heated water with cooler water in surface zone

25. Surface Temperature Changes
3/21/2011
Two factors affect surface temperatures:
Latitude-water along equator is warmer because it receives more direct sunlight (So temp would be lowest at the poles.)
Time of year more direct sun during summer, so surface zone is heated more

26. FYI - A Global Thermostat
3/21/2011
Ocean absorbs and holds energy from sunlight
Releases energy more slowly than land does; This keeps our temps from going to extremes every day/night
Ocean currents move warm water around our planet

27. Ocean Currents Oceans don’t just sit still
Currents move ocean water from place to place, moving nutrients and organisms with it
One very important kind of ocean current is upwelling

28. Upwelling
Defined as the movement of deep, cold, nutrient rich water to the surface
Because many nutrients sink to the bottom of the ocean, upwelling brings nutrients up where surface organisms can use them
These nutrient rich waters near the surface create productive fisheries

29. Upwelling Wind blows away from the shore, taking surface water with it
Deep water “wells up” to replace the surface water
This brings deep, cold,
nutrient rich water up to
the surface

30. Draw & label this diagram under the Infrared Ray section
Draw & label this diagram under the Infrared Ray section! Remember to draw the wavelength in the diagram!

31. Video Clips (15 min)
Exploring Oceans - Birth of an Ocean Oceans of the Earth - Why is the Sea Salty? - Upwelling – Observe how upwelling occurs -