1. The Chemical Composition of Seawater Winn Johnson 25 August 2015 Regional Maritime University

2. Seawater Chemistry Supports: ½ O 2 production CO 2 sink Food production

3. Topics Salts Carbonate system Inorganic Nutrients Trace Metals Organic Matter

4. Salts Density Freezing point Ionic strength Complexes with other ions Analytical challenges

5. Salt in the Ocean Cationsmmol/kgAnionsmmol/kg Na + 469.06Cl - 545.86 Mg 2+ 52.82SO 4 2- 28.24 Ca 2+ 10.28Br - 0.84 K+K+ 10.21F-F- 0.07 35 grams of salt / liter of seawater

6. Sources and Sinks of Chemical Constituents

7. Residence Time Residence Time (years) = ocean inventory (mol) / river inflow rate (mol y -1 ) or τ = reservoir / input or output Residence Time of Water = 1.35 x 10 18 m 3 / 3.5 x 10 13 m 3 y -1 = 40,000 years Residence Time of Na + = 647 x 10 18 moles / 8.1 x 10 12 = 80 x 10 6 years Residence Time of Cl - = 753 x 10 18 moles / 7.7 x 10 12 = 98 x 10 6 years These ions reside in the ocean ~3000 times longer than the water Assume steady state: inputs = outputs

8. Evaporation and Precipitation Drive Sea Surface Salinity Levitus, 1982

9. Global Sea Surface Salinity Emerson & Hedges, 2008

10. Section View of Salinity www.ewoce.org

11. Topics Salts Carbonate system Inorganic Nutrients Trace Metals Organic Matter

13. Carbonate System: Ocean Storage of Carbon CO 2 + H 2 O ⇄ H 2 CO 3 H 2 CO 3 ⇄ HCO 3 - + H + HCO 3 - ⇄ CO 3 2- + H +

14. As Atmospheric CO 2 Increases Ocean Chemistry Responds NASA

15. Ocean Acidification CO 2 + H 2 O ⇄ H 2 CO 3 H 2 CO 3 ⇄ HCO 3 - + H + HCO 3 - ⇄ CO 3 2- + H +

16. Ocean Acidification Can Impact Ocean Life Doney et al., 2009 CaCO 3  Ca 2+ + CO 3 2-

17. Oysters -affects development of oysters -already a problem on Northwest Coast of U.S.

18. Topics Salts Carbonate system Inorganic Nutrients Trace Metals Organic Matter

19. Nitrogen vs. Phosphorus Limitation Inorganic Total Karl et al., 2001

20. Nitrogen Cycle

21. Phosphorus Cycle PO 4 3- Organic Phosphorus

23. Increased Inputs of Nutrients: Eutrophication coastalwiki.org

24. Harmful Algal Blooms Toxins – Shellfish poisoning – Fish kills Hypoxia – Blooms drawdown oxygen so quickly that an area becomes anoxic driving organisms away or killing them A Noctiluca bloom in Union Bay, British Columbia. (Lisa M. Holm) Pseudo-nitzschia australis. (J. Rines)

26. Topics Salts Carbonate system Inorganic Nutrients Trace Metals Organic Matter

27. Trace Metals Micronutrients Iron can limit nitrogen fixation Human contamination

28. Trace Metal Profiles 1. Conservative2. Nutrient-like Profile 3. Particle-scavenged

29. Also hydrothermal sources of metals: iron coming off a hydrothermal vent on the mid-Atlantic ridge

30. Human Contributions to Trace Metal Concentrations also Detectable: Higher Concentrations of Lead in North Atlantic Deepwater

31. Topics Salts Carbonate system Inorganic Nutrients Trace Metals Organic Matter

32. Conclusions Many marine chemical constituents including trace metals, nutrients, and the carbonate system underlie a delicate a balance that supports the productivity of the ocean Chemicals also act as tracers of physical processes occurring in the ocean including deepwater circulation, inputs from hydrothermal vents, and upwelling The chemistry of the ocean is influenced by humans in many ways

33. Questions?