1. Ocean Chemistry

2. © 2006 Brooks/Cole, a division of Thomson Learning, Inc. Water Is a Powerful Solvent What are solutions and mixtures? A solution is made of two components, with uniform molecular properties throughout: The solvent, which is usually a liquid, and is the more abundant Component.

3. © 2006 Brooks/Cole, a division of Thomson Learning, Inc. The solute, often a solid or gas, is the less abundant component. Most mixtures are different from a solution, because solutions are homogenous mixtures. In a mixture the components retain separate identities, so it is NOT uniform throughout.

4. © 2006 Brooks/Cole, a division of Thomson Learning, Inc. Salinity  Salinity is the total quantity of dissolved inorganic solids in water. The heat capacity of water decreases with increasing salinity As salinity increases, freezing point decreases As salinity increases, evaporation slows

5. © 2006 Brooks/Cole, a division of Thomson Learning, Inc.  http://www.youtube.com/watch?v=qeZgJzt 3m04 http://www.youtube.com/watch?v=qeZgJzt 3m04

6. © 2006 Brooks/Cole, a division of Thomson Learning, Inc. A Few Ions Account for Most of the Ocean’s Salinity  Mostly Sodium Chloride  Also, Sulfate, Magnesium, Calcium and Potassium

7. © 2006 Brooks/Cole, a division of Thomson Learning, Inc. Fig. 7-6, p. 192

8. © 2006 Brooks/Cole, a division of Thomson Learning, Inc. Components of Ocean Salinity The Earth’s Crust washes into the sea to add to the salinity of the ocean.

9. © 2006 Brooks/Cole, a division of Thomson Learning, Inc.  http://videos.howstuffworks.com/discovery/ 31886-howstuffworks-show-episode-4- ocean-water-video.htm http://videos.howstuffworks.com/discovery/ 31886-howstuffworks-show-episode-4- ocean-water-video.htm

10. © 2006 Brooks/Cole, a division of Thomson Learning, Inc. The Ocean Is in Chemical Equilibrium Is the ocean becoming progressively saltier with age? No, the ocean is in chemical equilibrium. The proportion and amounts of dissolved solids remain constant. This concept is known as the “steady state ocean.“

11. © 2006 Brooks/Cole, a division of Thomson Learning, Inc. Gas Concentrations Vary with Depth  Oxygen is high at the surface and Carbon Dioxide is low. This is reversed as you increase in depth.  Carbon Dioxide makes up most of the dissolved gasses in the ocean.

12. © 2006 Brooks/Cole, a division of Thomson Learning, Inc. Dissolved Oxygen is very important to aquatic life  Higher temperatures reduce the amount of dissolved oxygen

13. © 2006 Brooks/Cole, a division of Thomson Learning, Inc. Fig. 7-12, p. 198 8.0 average ocean pH pH 7.07.58.59.0 0 Upper sunlit layer 2,000 1,000 Bottom of photo- synthetic zone 4,000 6,000 2,000 8,000 3,000 10,000 Depth (m) 12,000 Depth (ft) 4,000 CCD 14,000 5,000 16,000 18,000 6,000 8.0

14. © 2006 Brooks/Cole, a division of Thomson Learning, Inc. pH The Ocean’s Acid-Base Balance Varies with Dissolved Components and Depth

15. © 2006 Brooks/Cole, a division of Thomson Learning, Inc.  pH changes as Carbon dioxide dissolves or as carbon is changed into Carbonate in the shells of animals.  The ocean becomes more acidic with more dissolved CO 2

16. © 2006 Brooks/Cole, a division of Thomson Learning, Inc.  http://www.youtube.com/watch?v=MgdlAt4 CR-4 http://www.youtube.com/watch?v=MgdlAt4 CR-4  http://www.youtube.com/watch?v=d0kacyy LVB4 http://www.youtube.com/watch?v=d0kacyy LVB4