1. Composition of Seawater
Dissolved Substances Practice

2. What percentage of Sea Water weight is dissolved substances?
3.5%

3. What are the top 5 components of seawater?
Oxygen, hydrogen, chloride, sodium, sulfate

4. What are the 3 main dissolved gases?
Nitrogen, oxygen, carbon dioxide

5. Which gas is most abundant?
Nitrogen

6. How does nitrogen enter seawater
Exchange with the atmosphere

7. Give 2 ways oxygen enters seawater.
Exchange with atmosphere
Photosynthesis

8. How does carbon dioxide enter seawater?
Exchange with atmosphere
Respiration

9. Why is there more oxygen than CO2 if photosynthesis occurs only at the top and respiration occurs at all depths?
Because there are so many producers/phytoplankton

10. What are 3 biological processes that modify the concentration of gases at different depths?
Photosynthesis
Cellular respiration
Decomposition

11. Which biological process occurs only at the surface?
Photosynthesis

12. Which holds more dissolved gas: warm or cold?
Cold water

13. Which holds more gas: less salty or more salty?
Less salty water

14. Which holds more gas: high pressure or low pressure?

15. What does alkaline mean?
A solution is basic (pH above 7)

16. What is the average pH of seawater?8

17. What substance acts as a buffer in seawater?
Calcium carbonate (CaCO3)

18. What 3 characteristics control the density of seawater?
Temperature, salinity, pressure

19. What is the most important influence on the density of seawater?
temperature

20. What is the greatest influence in density in polar oceans?
salinity

21. What is a pycnocline?
Abrupt change in density with depth

22. What is a thermocline?
Abrupt change in temperature with depth

23. What does the prefix “iso” mean (as in isothermal and isopycnal)
equal