1. Unit 7 Chapter 24 Ocean Water
Section 1 Properties of Ocean Water

2. Temperature and Dissolved Gases
Ocean Water is not pure. There are gases and solids dissolved in it, small particles of matter and tiny organisms suspended within it.
Dissolved Gases
Two main gases dissolved are N2, O2, with a little of CO2,
Temperature and Dissolved Gases
Temperature affects the amount of gases dissolved. Warm water releases the gases back into the atmosphere.
The Ocean as a Carbon Sink
There is approximately 60 times more CO2 in the water as there is in the atmosphere.

3. Dissolved Solids Ocean water is 96. 5% pure, there are approximately 3
Dissolved Solids Ocean water is 96.5% pure, there are approximately 3.5% dissolved solids.
Most Abundant Element
There are approximately 75% chemical elements in ocean water. The 6 most abundant ones are Chlorine, Sodium, magnesium, sulfur, calcium and potassium. Halite (Chlorine and Sodium) makes up about 85% of the dissolved solids.
Sources of Dissolved Solids
The dissolved solids come from 3 main sources: volcano, chemical weathering and chemical reactions between sea water and new seafloor rock.
Salinity of Ocean Water
Salinity is the measure of the amount of dissolved salts and other solids in a given liquid. Ocean water is about 3.5% salts.
Factors that Change Salinity
Some factors that change the salinity are rain, snow and the rate of evaporation.

4. Temperature of Ocean Water Ocean temperatures vary depending on depth and location.
Surface Water
The mixing of water by waves and currents distributes heat downward to a depth of approximately meters.
The Thermocline
Thermocline is at a depth of about 1000 meters. The temperature drops rapidly over a small area. The temperature is approximately 5oC.

6. Deep Water Density of Water Color of Ocean Water
Deep water temperature is approximately 2oC. The colder the water, the denser it is.
Density of Water
The density of Pure Water is 1 g/cm3
The density of Ocean Water – g/cm3
As the water becomes colder it becomes denser. The densest water is in the Polar Regions, which is why it travels down to the warmer water in the tropics.
Color of Ocean Water
The color is determined by the way it absorbs or reflects sun light.
Why is Ocean Color Important?
Phytoplankton can change the color of water. It absorbs red and blue light and reflects green which changes the shade of blue. This helps biologists determine the health of the oceans.

7. Section 2 Life In the Oceans
Most organisms depend on two major functions for survival.
Sunlight and Nutrients
Ocean Chemistry and Marine Life
The chemistry of the oceans is a balance of dissolved gases and solids. Marine organisms help this by removing nutrients and gases and returning other nutrients and gases as waste.
Upwelling
Upwelling is the movement of deep, cold, nutrient rich water to the surface by means of wind and currents.

8. Marine Food Web Phytoplankton-
Single celled plants that float freely near the ocean surfaces. They are the base of the food chain.
Diatom-
One-celled plant with delicate thin shell made of silica.
Zooplankton-
They are microscopic animals that float in ocean water and eat phytoplankton or other small zooplankton. They also help moderate salinity.
Coral-
Tiny sea animal colonies fastened to rocky seafloors. Lives in temperatures between 18o and 21o C
Nekton-
They are a group of free swimming organisms including fish, reptiles, whales, squid and jellyfish.
Benthos – live on the ocean floor and shallow sunlit areas. Include such things as marine plants and animals. Some animals are oysters, sea stars and crabs.

9. Ocean Environments Benthic Zones Pelagic Zones
There 2 environments: benthic zone and pelagic zone
Benthic Zones
Pelagic Zones

10. Fresh Water from the Oceans
Section 3 Ocean Resources The oceans provide humans with food, minerals and transportation.
Fresh Water from the Oceans
Desalination is extracting fresh water from salt water. This is a very expensive process.
Methods of Desalination
Distillation – heating the water to remove the salt
Freezing – when salt water freezes, the first crystals that form are
fresh water. They are harvested from the top of the water.
Reverse Osmosis Desalination – using special membranes to filter out the salts, water is passed through under extreme pressure.
The salt is not passed through the membrane.

11. Mineral and Energy Resources
Salt and other valuable minerals come from the oceans. This is a very expensive process to extract them.
Petroleum
We produce about ¼ of the oil and natural gases by off shore drilling.
Nodules
A very expensive process to harvest these minerals: magnesium, iron, copper, nickel, cobalt and phosphates.
Trace Minerals
Magnesium and Bromine are found in trace amounts, too expensive to be profitable to harvest.

12. Food From the Ocean Fishing Aquaculture
This is our most important asset from the sea.
Fishing
This is the most significant food source. We have to be careful not to over fish the areas.
Aquaculture
This is the raising of aquatic plants and animals for human consumption. The problem with this is that farms are susceptible to pollution.

13. Ocean Water Pollution
Unfortunately the oceans have been a dumping ground for many years. We have dumped DDT, lead, gasoline, mercury, garbage, sewage and nuclear wastes. Not counting the countless ship wrecks that have added to this. Laws have been passed, but in some cases the damage is irreversible.