Ocean Chemistry – Chapter 6

1
Ocean Chemistry Chapter 6
Fe2
Ca2
NO3-
2
OUTLINE

• Foundations of Chemical Oceanography
• Periodic Table Valence Electrons
• Water Its Unique Properties
• Dissolved Elements in SeaWater
• Sources Sinks
• Carbon Dioxide the WORLD Ocean

3
SeaSalt (NaCl-) Maio Island, Cape Verde,
Africa -Nearly all minerals/ elements found in
the Ocean. . ..
4

• Foundations of Chemical Oceanography
• Joseph Gay-Lussay (1778-1850)
• 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

• Liebigs 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 Its 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 .. .. OCO
Covalent bond Sharing e- ?
OCO CO2
4 e- (.)
8
OUTLINE

• Foundations of Chemical Oceanography
• Periodic Table Valence Electrons
• Water Its Unique Properties
• Dissolved Elements in SeaWater
• Sources Sinks
• Carbon Dioxide the WORLD Ocean

9

• Water Its 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)
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• 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
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• 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 Worlds 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 Its 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. .
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• 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
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• 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 13. . .

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• 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

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• 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)
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• 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 Its 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

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• 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
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• 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!

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• 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
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Fig. 6.16
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Fig. 6.17
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Page 103
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Fig. 6.18
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Fig. 6.19
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Fig. 6.20
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Fig. 6.21
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Fig. 6.22
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Page 109
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PHOTOS
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Opener
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Page 91
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Fig. 6.1
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Figure 6a
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Fig. 6.14
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TABLES
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Tab. 6.1
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Tab. 6.2
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Tab. 6.3