Origins of Ocean Salts

10%

90% of rainfall is on the oceans

Watershed

River basinDrainage basinCatchment

Total land area that drains surface water to a common point.

Rain that falls anywhere within a given body of water's watershed or basin will eventually drain into that body of water.

AmazonWatershed

Atlantic

salts

Watersheds, Erosion and Dissolution

salts

Dissolution of salts; erosion of rocks and minerals

rain rain

Dissolved in water

water

water

water

Minerals and Erosion

KAlSi3O8

CaAl2Si2O8

NaAlSi3O8

K+, Ca2+, Na+, Si4+

Feldspars KAlSi3O8

CaAl2Si2O8

NaAlSi3O8

granite

http://upload.wikimedia.org/wikipedia/commons/c/c7/Sidari_Eroded_Rock.jpg

Dissolved Salts and Minerals

KClNaCl MgCl2

CaCO3

CaSO4

KAlSi3O8

CaAl2Si2O8

NaAlSi3O8

Rivers contain small amounts of dissolved salts that are delivered to the oceans

AmazonWatershed

Atlantic

KNa MgCl CaCO3

CaSO4

Si

Rivers < 500 mg/L

Oceans 35,000 mg/L

If rivers have low salt contents and theyare delivering salts to the oceans, why dooceans have such high salt contents?

Total Salts

Salts left behind

evaporation

The primary factor leading to ocean salinity.

Salts are delivered to the oceans in small amounts

Evaporation removes water from theoceans, but leaves the salts behind.

Rainfall on land dissolves more salts, whichare subsequently delivered to the oceans

What kind of Salts?

KCl NaCl MgCl2

CaCO3

CaSO4

River Water35.1520.3912.14 11.675.685.793.412.12

IonCarbonateCalciumSulfate SilicateChlorideSodium

MagnesiumPotassium

River Salt Composition

Dominated by Carbonate, Calcium, Sulfate, and Silicate

KAlSi3O8

CaAl2Si2O8

NaAlSi3O8

Ocean Salt CompositionIon

ChlorideSodiumSulfate

Magnesium Calcium

Potassium Carbonate

Silicate

Sea Water (%)55.0430.627.683.69 1.151.100.40.0004

Dominated by Chloride and Sodium

Na+ and Cl-(85% of total)

Cl- Na+

River Water35.1520.3911.6712.14 5.685.793.412.12

Sea Water.40

1.15.00047.68

55.0430.623.691.10

IonCarbonateCalciumSilicateSulfate ChlorideSodium

MagnesiumPotassium

Percentage of Total Dissolved Minerals

}79%

}85%

• Enrich Chloride and Sodium in ocean water

Remove Silica, Calcium, Carbonate from river water

Alterations

sodium, potassium, and ammonium salts are soluble

chloride, bromide and iodide salts are soluble.

NaCl Solubility 350 g/L

Solubility: ease of salt dissolution in water

Enriching Sodium and Chloride

Once these types of ions reach the oceans they stay dissolved

IonChlorideSodiumSulfate

Magnesium Calcium

Potassium Carbonate

Silicate

Sea Water (%)55.0430.627.683.69 1.151.100.40.0004

Both chloride salts and sodium salts areextremely soluble in water and do not

combine with other elements to form solids

• Enrich Chloride and Sodium in ocean water

Remove Silica, Calcium, Carbonate from river water

Alterations

SodiumChloride

Sulfate

Ca+2

Cl-

Na+

CO3-2

SO4-2

solid

Carbonate

Calcium

Precipitation and Carbonate Removal

Calcium and carbonate are at near saturation levels in oceans(amounts are close to a threshold for precipitation)

Ca2+ + CO32- = CaCO3

Corals

Mollusks

CaCO3

MgCO3

Marine Calcium and Magnesium Carbonate

Carbonate Deposition/Sedimentation

Foraminifera

Algae

Diatoms

Life and Silica

• Remove Silica, Calcium, Carbonate

Use silica as structural material

River Water35.1520.3911.675.685.793.412.12

12.14

Sea Water.40

1.15.000455.0430.623.691.107.68

IonCarbonateCalciumSilicateChlorideSodium

MagnesiumPotassium

Sulfate

Percentage of Total Dissolved Minerals

Next: Saltwater to Freshwater