1. How Does Salinity affect Density in the Ocean?

2. What is Salinity?
The total concentration of all dissolved inorganic solids
Many salts dissolved in seawater
NaCl, KCl

3. Why is the Ocean Salty?
Weathering of rocks on land (carried by rivers into the ocean)
Waves and surf erode coastal rocks and ocean bottoms
Salt domes

4. How do you Measure Salinity?
Measured in parts per thousand (ppt)
Salinity is expressed by the amount of salt found in 1,000 grams of water.
If the salinity of the ocean is 32ppt, it means there are 32 grams of salt in 1,000 grams of water
*Hydrometer, refractometer

5. Ocean Salinity
Varies very little overall, but there is a great deal of variation due to location
Approx. 32ppt
Lower salinity
areas near rivers, areas with high amounts of rainfall
High salinity
areas with a lot of evaporation/lots of sun

6. How does the addition of salt affect water?
Raises the boiling point
Decreases freezing temperature
Decreases heat capacity
Slows evaporation
Changes the density

8. Experiment How does salinity affect density in the ocean?
Draw your observations
Describe in words what you observe
Answer the above question

9. How do fish adapt to changes in salinity?

10. Diffusion & Osmosis Diffusion Osmosis
the tendency for a liquid, gas, or solute to flow from an area of high concentration to an area of low concentration
Osmosis
diffusion of water through a semipermeable membrane

11. Osmoregulators
Organisms that have a regulation process that allows them to adjust the water concentration within their cells

12. Osmoconformers
Organisms that cannot control their internal water concentration
Their internal salinity rises and falls with the surrounding environment
Example: marine invertebrates

13. Descriptors Euryhaline (“Eury” – wide, “haline” – salt)
Can tolerate significant fluctuations
Example: salmon & manatees
Stenohaline (“Steno” – narrow)
Cannot tolerate significant fluctuations
Example: goldfish & grouper

14. Video Clips
Dead Sea Dying
Bowling Ball

16. How does Temperature Affect Density in the ocean?

17. Experiment What is the effect of temperature on density?
How does this relate to the ocean?
Draw your observations
Describe in words what you observe
Answer the above questions

18. What is the Effect of Temperature on Density?
Water becomes more dense as it cools
However, at about 4°C (right before the water freezes), water becomes less dense
Ice Floats

19. Ocean Water Density
Because temp and salinity affect water density, seawater stratifies (forms layers)
Thermocline: an abrupt change in temp leading to 2 distinct layers
Halocline: an abrupt change in salinity leading to 2 distinct layers
Pycnocline: Thermocline and halocline together creating a boundary between layers of differing water density

21. Experiment: Layering Liquids
Using what you have learned this week, can you use the 4 liquids to show stratified layers without mixing?

22. Key Red: Hot and Salty Blue: Cold and Salty Yellow: Hot and Fresh
Green: Cold and Fresh

23. Conclusions:
Answer the questions given to you on a separate piece of paper in complete sentences!

25. National Geographic Article
Read the article individually
Answer the questions as a group
Nutrients in the Ocean:
Phosphate, Nitrate, Silica, Iron…things typically dissolved in the ocean that plants and animals need to survive

26. Describe the importance of the ocean circulation pattern in the Southern Hemisphere.
How do differences in ocean water density make the circulation pattern possible?
According to the article, which has a greater impact on density in the ocean, salinity or temperature? Suggest a possible reason for this.
Define Biological Productivity
How might global warming affect the conveyor belt?