1. Ocean Chemistry – Chapter 6
Fe2+
Ca2+
NO3-

2. OUTLINE Foundations of Chemical Oceanography
Periodic Table – Valence Electrons
Water – It’s Unique Properties
Dissolved Elements in SeaWater
Sources & Sinks
Carbon Dioxide & the WORLD Ocean

3. SeaSalt (Na+Cl-)
Maio Island, Cape Verde, Africa
-Nearly all minerals/ elements found in the Ocean. . ..

4. Foundations of Chemical Oceanography
Joseph Gay-Lussay ( )
Introduces the idea of the “WATER Column”
Denotes depth-dependency of many ocean properties
(esp. elements/minerals, e.g CaCO3 “calcite”)
ALGAE
Shells totally dissolve

5. “Liebig’s Law of Minimum”
What does it state?
Growth of plants controlled by a single element
(required by plant) - but available at LOWEST rate of supply
Challenge Question
In this schematic which element would be rate limiting?

6. OUTLINE Foundations of Chemical Oceanography
Periodic Table – Valence Electrons
Water – It’s Unique Properties
Dissolved Elements in SeaWater
Sources & Sinks
Carbon Dioxide & the WORLD Ocean

7. Recall - Periodic Table _Valence Electrons
Outer valence electrons (= e-) participates in bonding of Elements
6 e- = (.)
e.g.
CO2 carbon dioxide
O::C::O
‘‘ ‘’
Covalent bond
Sharing e- 
O=C=O
CO2
4 e- = (.)

8. OUTLINE Foundations of Chemical Oceanography
Periodic Table – Valence Electrons
Water – It’s Unique Properties
Dissolved Elements in SeaWater
Sources & Sinks
Carbon Dioxide & the WORLD Ocean

9. - - + - - - - + - - - + - - - + + + + + Water – It’s Unique Properties: O : H H - - + O- - - H+ - - + - - - + - - O- H+ H+ - + +
Electro + part attract electro – part
(Opposites attract) H+ + + +
H2O molecules form Hydrogen bonds with other H2O molecules. . .
(see above)  what makes water 
b/c of +/- nature of H2O = great at DISSOLVING substances
– aka UNIVERSAL SOLVENT (something that DISSOLVES)

10. Dissolving Power of H2O Water ~ universal (solvent)
What trying to dissolve, aka = solute (e.g. salt)
When too much of solute/solvent  precipitation (e.g. sugar crystals or salt)
Compounds of Opposite charge molecules =
“ionic compounds” – these dissolve best in H2O
Anions (-) charge, e.g. Cl-
Cations (+) charge, e.g. Na+

11. Salt, a solute, dissolves in water, a solvent
Until a “saturation point” is reached
Challenge Question?
How can this be overcome?
Increase temp. . .
Solute dissolves

12. Airborne particles and the World’s Ocean
Aeolian (air/wind) Input
Red clay (to sediments)
trace elements ~Iron (Fe2+)
Rate limiting nutrient for
plankton  algae bloom?
With Iron comes
increased Plankton blooms
Plankton Blooms produce
Dimethyl Sulfide (DMS)
 Cloud condensation nuceli
-Influences cloud formation
MODIS satelite
Fe2+
Fe2+
Fe2+
Fe2+
Dust from
Africa . . .
bloom
bloom

13. OUTLINE Foundations of Chemical Oceanography
Periodic Table – Valence Electrons
Water – It’s Unique Properties
Dissolved Elements in SeaWater
Sources & Sinks
Carbon Dioxide & the WORLD Ocean

14. Dissolved Elements of SeaWater
The major constituents (elements of SeaWater)

15. Dissolved Elements in SeaWater
The major constituents (elements of SeaWater)
Know the big 5 (conservative ~ lots)

16. Oceanographers
Use conductivity at diff. temps
To determine salinity
Throughout the oceans. . .
Salinity affects density 
Deep water - Ocean Circulation/Currents. . .Climate
To be continued. .

17. Minor Constituents of Seawater
Minor constituents (≤0.1 mMol/ kg, very dilute see Table 6.1)
trace elements (Iron, Silica)
(secondary metabolites – venoms, poisons)
Marine Natural Products
Cone Snail- Conus magnus
Conotoxins (ziconotide- Prialt®)
1000Xs more potent then Morphine!
morphine
ziconotide

18. Biologically Important Nutrients: 2 classes:
Macronutrients
Nitrogen (N)
Phosphorous (P)
Potassium (K)
micronutrients
Iron (Fe)
Silica (Si)
Availability &
Supply of nutrients
Effect photosynth
in world ocean
More in Chap

19. Dissolved Organic Matter (DOM)
Dissolved Carbon “C” from
bacteria decomposition
Leaky marine organisms (incontinent)
Terrestrial sources
Important in Carbon Cycle
Add to Oceans Color
Can be seen by satellite
Helps to track/model
Carbon Cycle Chp.14
CO2 – climate change

20. Dissolved Gasses - Challenge Questions
What are Zones of decreased and no dissolved Oxygen called?
1) Hypoxic Zone – decreased O2 levels
2) Anoxic Zone – no O2 ! 
Do gasses dissolve better with
increased or decreased temperature?
Decreased temperature
Lots of nutrients (Missip river runoff) lead to
Algae blooms - Zoo plankton - use up all O2 –
( Big fish suffocate)

21. Confirming your Knowledge
What are the 5 major elemental constituents of SeaH2O?
Cl, Na, S, Mg, Ca
What are the Macro and micronutrients?
N (nitrogen), P (phosphorous), K (potassium) (Macro)
Fe, Si (micro)

22. OUTLINE Foundations of Chemical Oceanography
Periodic Table – Valence Electrons
Water – It’s Unique Properties
Dissolved Elements in SeaWater
Sources & Sinks
Carbon Dioxide & the WORLD Ocean

23. Sources ( provide) & Sinks (remove) Minerals etc.
The above determine concentration of elements in SeaWater
CONTINENTAL Weathering: A Source
Na from Continental Weathering
Cl- from Vents? Volcanoes? (acid rain)
not f/ river rocks (recycled as spray-Ocean Waves

24. Hydrothermal Vents: A Source & SINK
Sources ( provide) & Sinks (remove) Minerals etc.
Hydrothermal Vents: A Source & SINK
+/- Minor source
Consume other elements
Lead, Sulfur, Copper, Iron, Cobalt, Ag
Mostly gypsum & Zinc

25. Residence Times of Elements
When sources/ sinks in balance – ocean is steady state
At steady state – can define the amt. of time
For total mass of an Element (e.g. Na) to be replaced
aka Residence Time (how long it is in the ocean)
Residence Time
= mass of element present / rate of input or removal Na
1.472 x 1011 kg yr-1 tons/ year / 2 x108 tons/yr-1 Na/year = 70 million years!

26. Final Thoughts Turn in Long Lab Field Trip (HW-1)
Please do HW-2 (due July 7th)
Wed – Final Chemical Oceanography -CO2_The Oceans & Ocean Physics
Fe2+
NO3-
Ca2+

27. Fig. 6.16

28. Fig. 6.17

29. Page 103

30. Fig. 6.18

31. Fig. 6.19

32. Fig. 6.20

33. Fig. 6.21

34. Fig. 6.22

35. Page 109

36. PHOTOS

37. Opener

38. Page 91

39. Fig. 6.1

40. Figure 6a

41. Fig. 6.14

42. TABLES

43. Tab. 6.1

44. Tab. 6.2

45. Tab. 6.3