1. Ocean Water

2. Why is the ocean salty?

3. What is a salt?

4. Salts are made from Ions

5. Elements Electrons (-) Elements in the periodic
table have equal numbers
of protons (+) and electrons (-).
They are electrically neutral
Protons (+)

6. Ions Ions are stable forms of elements that acquire
an electrical charge by gaining or losing electrons
Elemental Sodium (Na)
11 protons (+), 11 electrons (-)
Sodium ion (Na+)
11 protons (+), 10 electrons (-)
By losing an electron, sodium has more protons than
electrons and becomes positively charged.
Na - 1e- = Na+

7. + Sodium Na Na Na+ 11 protons e- e- e- Much more stable
It is anxious, if fact, desperate to lose that electron and assume its more stable form.

8. 2Na + 2H20 2Na OH- + H2

9. Ions Ions are stable forms of elements that acquire
an electrical charge by gaining or losing electrons
Elemental Chlorine (Cl)
17 protons (+), 17 electrons (-)
Chloride ion (Cl-)
17 protons (+), 18 electrons (-)
By gaining an electron, chlorine has more electrons than
protons and becomes negatively charged.
Cl + 1e- = Cl-

10. Chlorine _ e- e- e- e- Cl
Cl-
17 protons
Much more Stable

11. Elements that lose electrons and become
positively charged are called cations.
Na+, K+, Ca2+, Mg2+, Cu2+, Fe3+
Elements that gain electrons and become
negatively charged are called anions.
Cl-, Br-, F-, I-
CO32-, SO42-, PO4-3
oxoanions

12. Salts Salts are formed by combining cations and
anions to form solids that have no charge.
Cations: K+, Na+, Mg2+, Ca2+
Anions: Cl-, CO3-2, SO4-2
K Cl- = KCl
Na Cl- = NaCl
KCl, NaCl, MgCl2, CaCO3, CaSO4

13. KCl K+ + Cl- NaCl Na+ + Cl-
Conversely, if solid salts are mixed with water
they dissolve and the ions go into solution
solid
solution
Water
KCl K Cl-
Water
NaCl Na Cl-
CaCO3
CaSO4
Ca+2 and CO3-2
Ca+2 and SO4-2

14. Dissolution
Cl- Cl Cl Na Cl Cl
NaCl
Na+

15. Oceans have enormous amounts of salt (ions) dissolved in the water.
Where does it come from?

16. 90% of rainfall is on the oceans
10%
So far, we have considered the largest portion of the hydrologic cycle, the oceans, particularly with respect to their integrative effect on climate and heat distribution on earth. We’ve also discussed precipitation and rainfall and it’s causes. Remember that 90% of surface evaporation comes from the ocean and in turn about 90% of all precipitation returns to the oceans. This leaves only 10% that reaches the land. We’ll now begin to examine what happens to precipitation that strikes land in the form of fresh water; specifically, rivers, lakes, soil water, and groundwater.
90% of rainfall is on the oceans

17. Fate of Precipitation to Land
Evaporation / Transpiration
Infiltration to Soil/Soil flow
Overland Flow (Runoff)
Aquifers/ Groundwater
Exchange and transport of freshwater in the terrestrial environment is complex and varied, but basically, water that falls to the earth is subject to well known fates. Much of precipitation falling on land is subject to evaporation or transpiration by plants and is therefore returned to the atmosphere. Another fraction infiltrates the soil becoming part of the soil water reservoir. However, if rainfall volume exceeds the ability of the soil to accept it, water flows over the land as runoff. Water that infiltrates the soil is constantly in flux. Some moves within the soil or is stored there. Another fraction is withdrawn by plants or moves to lakes, rivers and streams. Some, however is subject to percolation to groundwater. Aquifer or groundwater storage and transport is vitally important and comprises the largest of our readily available freshwater resources.
Streams, Rivers, Lakes

18. Watershed River basin Drainage basin Catchment
Total land area that drains surface water to a common point.
River basin
Drainage basin
Catchment
Recall that a watershed is the total land area that drains water to a common point. Thus, in terms of freshwater resources, the watershed encompasses all of the available freshwater reservoirs and the exchange of freshwater between them.
Rain that falls anywhere within a given body of water's watershed or basin will eventually drain into that body of water.

19. Amazon
Watershed
Atlantic

20. Watersheds, Erosion and Dissolution
rain
rain
salts
salts
Dissolution of salts; erosion of rocks and minerals

21. Minerals and Erosion Feldspars KAlSi3O8 CaAl2Si2O8 NaAlSi3O8
water
KAlSi3O8
CaAl2Si2O8
NaAlSi3O8
water
K+, Ca2+, Na+, Si4+
granite
water
Dissolved in water

23. Dissolved Salts and Minerals
KAlSi3O8
CaAl2Si2O8
NaAlSi3O8
KCl
NaCl
MgCl2
CaCO3
CaSO4
Rivers contain small amounts of dissolved salts that are delivered to the oceans

24. Amazon
Watershed
Atlantic K Na Mg Cl Ca
CO3
SO4 Si

25. Total Salts If rivers have low salt contents and they
Rivers < 500 mg/L
Oceans 35,000 mg/L
If rivers have low salt contents and they
are delivering salts to the oceans, why do
oceans have such high salt contents?

26. evaporation
Salts left behind
The primary factor leading to ocean salinity.

27. Salts are delivered to the oceans in small amounts
Evaporation removes water from the
oceans, but leaves the salts behind.
Rainfall on land dissolves more salts, which
are subsequently delivered to the oceans

28. Microcosm: The Dead Sea
34% salt content
Endorheic sea
Elevation: 1400 ft
below sea level
Lowest dry elevation on earth
The sea is called "dead" because its high salinity means no fish or macroscopic aquatic organisms can live in it, although bacteria and microbial fungi are present. The salinity of the Dead Sea varies according to depth with the surface water being approximately 15% saline (5 times the average ocean salinity) and water near the bottom being saturated, such that salt precipitates out of solution onto the sea floor. The mineral content of the Dead Sea is significantly different from that of ocean water, consisting of approximately 53% magnesium chloride, 37% potassium chloride and 8% sodium chloride (table salt) with the remainder comprised of various trace elements.
The concentration of SO4 ions is very low, and the bromine ions concentration is the highest of all waters on Earth. Chlorides neutralize most of the calcium ions in the Dead Sea and its surroundings. While in other seas NaCl is 97%, in the Dead Sea the quantity of the NaCl is only percent. The water temperature goes from 19 degrees Celsius in February to 31 degrees Celsius in August.
59 inches of Evaporation/yr

29. The Dead Sea is Dying 10% of natural flow now reaches the sea.
Salt Works
1973
10% of natural
flow now reaches
the sea.
Salt works, installed in what was the shallow southern basin of the Sea prior to its separation from the northern basin in the 80s, also contributes to the shrinking of the Sea. The evaporation ponds fed by water pumped in main water body are said to be responsible for 25-30% of the total evaporation of Dead Sea water.
1987
Sea levels are dropping by 3 ft/yr
2000

30. Great Salt Lake 5 to 27% Salt Content Jordan Weber Bear
Remnant of Lake Bonneville. Catastrophic water loss around 15,000 years ago lower lake bonneville by about 350 feet.
Railroad causeway
one inch to six feet thick
Remnant of Lake Bonneville
(15,000 years ago)

31. Amu Darya and Syr Darya rivers
The Aral Sea (up to 8% salinity)
60% loss in area
80% loss in volume
In 1965, USSR tapped the lake for irrigation to develop surrounding economies. Today the sea is less than 1/2 its previous area. Increased salinity has killed all the fish (4.5%). 95% of its former inputs are now diverted. It was the 4th largest lake in 1950 and now has lost 60% of its area and 80 % of its volume.
Amu Darya and Syr Darya rivers

32. Oceans and Rivers
4 billion tons of dissolved salts to the ocean annually

33. What kind of Salts?

34. River Salt Composition
Carbonate
Calcium
Sulfate
Silicate
Chloride
Sodium
Magnesium
Potassium
River Water
35.15
20.39
12.14
11.67
5.68
5.79
3.41
2.12
KCl
NaCl
MgCl2
CaCO3
CaSO4
KAlSi3O8
CaAl2Si2O8
NaAlSi3O8
Dominated by Carbonate, Calcium, Sulfate, and Silicate

35. Ocean Salt Composition
Chloride
Sodium
Sulfate
Magnesium
Calcium
Potassium
Carbonate
Silicate
Sea Water (%)
55.04
30.62
7.68
3.69
1.15
1.10
0.40
.0004
2.9% Na+ and Cl-
In the beginning the primeval seas must have been only slightly salty. But ever since the first rains descended upon the young Earth hundreds of millions of years ago and ran over the land breaking up rocks and transporting their minerals to the seas, the ocean has become saltier. It is estimated that the rivers and streams flowing from the United States alone discharge 225 million tons of dissolved solids and 513 million tons of suspended sediment annually to the sea. Recent calculations show yields of dissolved solids from other land masses that range from about 6 tons per square mile for Australia to about 120 tons per square mile for Europe. Throughout the world, rivers carry an estimated 4 billion tons of dissolved salts to the ocean annually. About the same tonnage of salt from the ocean water probably is deposited as sediment on the ocean bottom, and thus, yearly gains may offset yearly losses. In other words, the oceans today probably have a balanced salt input and outgo.
Past accumulations of dissolved and suspended solids in the sea do not explain completely why the ocean is salty. Salts become concentrated in the sea because the Sun's heat distills or vaporizes almost pure water from the surface of the sea and leaves the salts behind. This process is part of the continual exchange of water between the Earth and the atmosphere that is called the hydrologic cycle. Water vapor rises from the ocean surface and is carried landward by the winds. When the vapor collides with a colder mass of air, it condenses (changes from a gas to a liquid) and falls to Earth as rain. The rain runs off into streams which in turn transport water to the ocean. Evaporation from both the land and the ocean again causes water to return to the atmosphere as vapor and the cycle starts anew. The ocean, then, is not fresh like river water because of the huge accumulation of salts by evaporation and the contribution of raw salts from the land. In fact, since the first rainfall, the seas have become saltier.
(85% of total)
Dominated by Chloride, Sodium, and Sulfate

36. } } Percentage of Total Dissolved Minerals River Water Ion Sea Water
Carbonate
Calcium
Silicate
Sulfate
Chloride
Sodium
Magnesium
Potassium
River Water
35.15
20.39
11.67
12.14
5.68
5.79
3.41
2.12
Sea Water
.40
1.15
.0004
7.68
55.04
30.62
3.69
1.10 }
79% }
85%
Carbonate, calcium and silicate are disappearing
Chloride and sodium are appearing

37. River Water has high amounts of
Calcium, Carbonate, and Silicate
Ocean Water has high amounts of
Sodium and Chloride
If ocean salts come from rivers, some process
is removing calcium, carbonate, and silicates
from the river water, and sodium and chloride
are being enriched in ocean waters.

38. Alterations Enrich Sodium, Chloride in ocean water
Remove Silica, Calcium, Carbonate
from river water
No known biological process removes sodium from the sea. Therefore, it is very abundant in sea water. Certain constituents in sea water, such as calcium, magnesium, bicarbonate, and silica, are partly taken out of solution by biological organisms, chemical precipitation, or physical-chemical reactions Part of the explanation is the role played by marine life -- animals and plants -- in ocean water's composition. Sea water is not simply a solution of salts and dissolved gases unaffected by living organisms in the sea. Mollusks (oysters, clams, and mussels, for example) extract calcium from the sea to build their shells and skeletons. Foraminifers (very small one-celled sea animals) and crustaceans (such as crabs, shrimp, lobsters, and barnacles) likewise take out large amounts of calcium salts to build their bodies. Coral reefs, common in warm tropical seas, consist mostly of limestone (calcium carbonate) formed over millions of years from the skeletons of billions of small corals and other sea animals. Plankton (tiny floating animal and plant life) also exerts control on the composition of sea water. Diatoms, members of the plankton community, require silica to form their shells and they draw heavily on the ocean's silica for this purpose

39. NaCl Solubility 350 g/L Enriching Sodium and Chloride
Solubility: ease of dissolution in water
sodium, potassium, and ammonium salts are soluble
chloride, bromide and iodide salts are soluble.
Once these types of ions reach the oceans they stay dissolved
350 g/L = 0.75 lb/L
NaCl Solubility 350 g/L

40. Calcium Carbonate Removal
Remove Silica, Calcium, Carbonate
Incorporate into shells of marine invertebrates
Depends on pH and Co2
Ca2+ + CO32- = CaCO3

41. Life and Silica Diatoms Use silica as structural material
Remove Silica, Calcium, Carbonate
Diatoms
Diatoms (Gr. dia 'through'; tomos 'cutting', i.e., "cut in half") are a major group of eukaryotic algae, and are one of the most common types of phytoplankton. Most diatoms are unicellular, although some form chains or simple colonies. A characteristic feature of diatom cells is that they are encased within a unique cell wall made of silica. These walls show a wide diversity in form, some quite beautiful and ornate, but usually consist of two symmetrical sides with a split between them, hence the group name.
Diatoms in both fresh and salt water extract silica from the water to use as a component of their cell walls (“test”, “shell”). Likewise, some holoplanktonic protozoa (Radiolaria), some sponges, and some plants (leaf phytoliths) use silicon as a structural material.
The richest sources of diatom fossils are deposits of their skeletons known as diatomite, or diatomaceous earth. This mineral was formed as ancient diatoms died and settled to the bottom of lakes or oceans. Today, they form large deposits of white chalky material, which is mined for use in cleansers, paints, filtering agents, and abrasives. Many toothpastes contain bits of fossil diatoms. The Bacillariophyta are the diatoms. With their exquisitely beautiful silica shells
Use silica as structural material

42. Percentage of Total Dissolved Minerals
River Water
35.15
20.39
11.67
5.68
5.79
3.41
2.12
12.14
Sea Water
.40
1.15
.0004
55.04
30.62
3.69
1.10
7.68
Ion
Carbonate
Calcium
Silicate
Chloride
Sodium
Magnesium
Potassium
Sulfate

43. Other Constituents in Ocean Water

44. The Oceans and Carbon Dioxide
Chemical interaction between the Oceans and the Atmosphere

45. Gases Dissolve in Water
Constant interchange of gases at the surface of the oceans
Oxygen slips into "pockets" that exist in the loose hydrogen-bonded network of water molecules without forcing them apart. The oxygen is then caged by water molecules, which weakly pin it in place.
dissolution 45

46. Composition of the Atmosphere
Gases
Nitrogen 78.1%
Oxygen 20.9%
Argon 0.93%
CO %

47. Oxygen Solubility: 0.043 g/L (20oC) 47
The diffusion of oxygen is often of great importance in relation to water, particularly in lakes and rivers. Oxygen contents dictate in many ways the life limits of aquatic organisms. We will explore in some detail the factors controlling oxygen contents in water particularly in relation to temperature. The solubility of oxygen is greater in colder water than in warm water. 47

48. Carbon Dioxide - + O C O -

49. Carbon Dioxide

50. CO2 Solubility = 1.69 g/L Between 1800 and 1994, the
380 ppm
CO2
Solubility = 1.69 g/L
(Oxygen Solubility: g/L)
Analysis of CO2 levels in ice cores have shown scientists that for the 400,000 years before the industrial revolution began in the 1800s, atmospheric CO2 concentrations remained between 200 and 280 parts per million. Today CO2 levels are reaching 380 parts per million in the atmosphere. “If the ocean had not removed 118 billion metric tons of anthropogenic carbon between 1800 and 1994, the CO2 level in the atmosphere would be about 55 parts per million greater than currently observed,” said Sabine.
ocean removed about 118 billion metric tons.
Between 1800 and 1994, the
48 percent of all fossil fuel emissions
Middle
Ages
Industrial
Revolution 50

51. Present and Future Problems
Gases/Heat
Gas
Solubility = 1.69 g/L
Oxygen Solubility: g/L

53. Carbon Dioxide also is an Acid

54. Dissolution of Carbon Dioxide
CO2 + H2O H2CO3
H2CO3 H HCO3-
H+ is acid
CO2
Water
Acid
Acids (H+) are reactive and dissolve a number of substances

55. Copper and Silver Cleaning:
CuO + 2HCl → CuCl2 + H2O
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Taken in a place with no name (See more photos or videos here)
Ag2O + 2 HCl → 2 AgCl + H2O
CaCO3
Fe2O3 + 6H Fe H2O
Fe2O3
CaCO3 + H Ca HCO3-

56. Invertebrate shells and skeletons largely CaCO3
“It isn’t just the coral reefs which are affected – a large part of the plankton in the Southern Ocean, the coccolithophorids, are also affected. These drive ocean productivity and are the base of the food web which supports krill, whales, tuna and our fisheries. They also play a vital role in removing carbon dioxide from the atmosphere, which could break down
WASHINGTON - Nearly half the excess carbon dioxide emitted into the air by humans over the past two centuries has been taken up by the ocean, according to a study published in the new issue of the journal Science. An accompanying report stated that if the trend continues, it could damage the ability of corals, snails and plankton to make their shells.
Invertebrate shells and skeletons largely CaCO3
Corals, “lithic” plankton, clams, oysters 56

57. CO2 H+ CaCO3 + H+ Ca2+ + HCO3- Water pH change: 8.179 to 8.104
Acidification of the oceans
Inhibits the calcification and
growth of invertebrates
17% increase in H+ concentrations.
“It isn’t just the coral reefs which are affected – a large part of the plankton in the Southern Ocean, the coccolithophorids, are also affected. These drive ocean productivity and are the base of the food web which supports krill, whales, tuna and our fisheries. They also play a vital role in removing carbon dioxide from the atmosphere, which could break down
Analysis of CO2 levels in ice cores have shown scientists that for the 400,000 years before the industrial revolution began in the 1800s, atmospheric CO2 concentrations remained between 200 and 280 parts per million. Today CO2 levels are reaching 380 parts per million in the atmosphere. “If the ocean had not removed 118 billion metric tons of anthropogenic carbon between 1800 and 1994, the CO2 level in the atmosphere would be about 55 parts per million greater than currently observed,” said Sabine.
The results of our study were visibly obvious and may provide a glimpse into the future. We saw a 92-percent decrease in the area covered by crustose coralline algae in the tanks with lower pH compared with tanks at the pH level of today's ocean. Non-calcifying fleshy algae increased by 52 percent," said Kuffner. "These findings suggest that at lower pH, the reef-building algae could be much less competitive on future coral reefs."
Based on our present knowledge, it appears that as seawater CO2 levels rise the skeletal growth rates of calcareous plankton will be reduced as a result of the effects of CO2 on calcification,” said Victoria Fabry, a biologist at California State University at San Marcos and a paper co-author. Recent studies have shown that calcification rates can drop by as much as 25 to 45 percent at CO2 levels equivalent to atmospheric concentrations of 700 to 800 parts per million. Those levels will be reached by the end of this century if fossil fuel consumption continues at projected levels.
Analysis of coral cores shows a steady drop in calcification over the last 20 years 57

58. Coral Reef Bleaching
Scleractinian corals receive their nutrient and energy resources in two ways. They use the traditional cnidarian strategy of capturing tiny planktonic organisms with their, as well as having a symbiotic relationship with a single cell algae known as zooxanthellae. Zooxanthellae are autorophic microalgaes
Zooxanthellae live symbiotically within the coral polyp tissues and assist the coral in nutrient production through its photosynthetic activities. These activities provide the coral with fixed carbon compounds for energy, enhance calcification ,and mediate elemental nutrient flux. The host coral polyp in return provides its zooxanthellae with a protected environment to live within, and a steady supply of carbon dioxide for its photosynthetic processes. The symbiotic relationship allows the slow growing corals to compete with the faster growing multicellular algaes because the tight coupling of resources and the fact that the corals can feed by day through photosynthesis and by night through predation.  
Three hypotheses have been advanced to explain the cellular mechanism of bleaching, and all are based on extreme sea temperatures as one of the causative factors. High temperature and irradiance stressors have been implicated in the disruption of enzyme systems in zooxanthellae that offer protection against oxygen toxicity. Photosynthesis pathways in zooxanthallae are impaired at temperatures above 30 degrees C, this effect could activate the disassociation of coral / algal symbiosis. Low- or high-temperature shocks results in zooxanthellae low as a result of cell adhesion dysfunction. This involves the detachment of cnidarian endodermal cells with their zooxanthellae and the eventual expulsion of both cell types.
Corals live in very nutrient poor waters and have certain
zones of tolerance to water temperature, salinity,
UV radiation, opacity, and nutrient quantities.  58

59. Anthropogenic Inputs

60. Homework II Oceanic Dead Zones
This is an excerpt from a news story from June 21 by the AP concerning recent
Mid-west flooding and its potential impact on the dead zone in the Gulf of Mexico.
Flood, size of gulf dead zone linked
Extra farm runoff in the Mississippi to increase area with no oxygen
Associated Press
June 21, 2008
WASHINGTON - Floodwaters loaded with farm runoff are heading down the
Mississippi River, and scientists fear that the deluge will sharply increase the expected
dead zone this summer in the Gulf of Mexico, covering an area the size of Maryland. The dead zone is a region of the gulf that becomes starved for oxygen
during much of the summer and cannot support fish or other sea life. There are hundreds of dead zones around the world that wreak havoc on marine
ecology and cut off vast areas for commercial fishing. The zone in the gulf
is the largest in the Western Hemisphere.