Oceans Oceans

Four Oceans of Planet EarthFour Oceans of Planet Earth

• NameNamess

• PacificPacific

• AtlantiAtlantic c

• ArticArtic

• IndianIndian

• CharacteristicsCharacteristics

• LargestLargest

• Closest to usClosest to us

• ColdestColdest

• SmallestSmallest

Ocean Water Chemistry (12-Ocean Water Chemistry (12-3)3)• Ocean water contains 35 parts of Ocean water contains 35 parts of

dissolveddissolved salts for every 1000 parts of water. This salts for every 1000 parts of water. This

creates a body of water that has 3.5% creates a body of water that has 3.5% salinity.salinity.

• The dissolved salts are as follows:The dissolved salts are as follows:- Chloride 55.0%Chloride 55.0% Sodium 30.6%Sodium 30.6%- Sulfate 7.7%Sulfate 7.7% Magnesium 3.7%Magnesium 3.7%- Calcium 1.2%Calcium 1.2% Potassium 1.1%Potassium 1.1%

How do the dissolved salts get How do the dissolved salts get there?there?

• Volcanoes release gasses into the Volcanoes release gasses into the atmosphere and they fall into the atmosphere and they fall into the oceans.oceans.

• Rivers constantly carry and deposit Rivers constantly carry and deposit dissolved substances in from the dissolved substances in from the continents.continents.

• All dissolved substances are free All dissolved substances are free floating ions, which make water floating ions, which make water “charged” electrically. That’s why “charged” electrically. That’s why lightning is attracted to it.lightning is attracted to it.

So why doesn’t the salinity get So why doesn’t the salinity get higher?higher?

• As rivers and volcanoes deposit As rivers and volcanoes deposit materials, plants and animals take materials, plants and animals take them out for nutrition, to make them out for nutrition, to make shells, for their bones.shells, for their bones.

How does salinity affect the How does salinity affect the ocean?ocean?

• Salt water freezes at -2 Salt water freezes at -2 00C (fresh water C (fresh water freezes at 0 freezes at 0 00C.)C.)

• Salt water is more dense than fresh water, Salt water is more dense than fresh water, causing objects to be more buoyant in salt causing objects to be more buoyant in salt water – You can float better in the salty water – You can float better in the salty water!water!

• The Dead Sea has the highest salinity on this The Dead Sea has the highest salinity on this planet. Which allows this person to “sit” on planet. Which allows this person to “sit” on the ocean water.the ocean water.

What can cause the salinity What can cause the salinity rate to change from the 3.5%?rate to change from the 3.5%?

• Near the surface of the ocean, large amounts Near the surface of the ocean, large amounts of precipitation can lower the salinity.of precipitation can lower the salinity.

• Near the poles, freezing temperatures create Near the poles, freezing temperatures create ice, but leaves the salt behind which ice, but leaves the salt behind which increases the salinity.increases the salinity.

• Near the bottom of very large rivers (Amazon Near the bottom of very large rivers (Amazon and Mississippi) that deposit huge amounts of and Mississippi) that deposit huge amounts of fresh water from land will decrease the fresh water from land will decrease the salinity.salinity.

Other Ocean Properties –Other Ocean Properties –Water TemperaturesWater Temperatures

• Surface water temperatures are different Surface water temperatures are different because the temperature of the air is because the temperature of the air is different.different.

• Near the poles the surface ocean water Near the poles the surface ocean water temperature is cold, near the equator the temperature is cold, near the equator the surface water temp. is warmer.surface water temp. is warmer.

• Cold water is more dense so it sinks, and hot Cold water is more dense so it sinks, and hot water is less dense so it rises, causing a water is less dense so it rises, causing a mixing of the water in a very large circular mixing of the water in a very large circular pattern.pattern.

Other Ocean Properties –Other Ocean Properties –Gases in the ocean waterGases in the ocean water

• Ocean organisms need dissolved Ocean organisms need dissolved gasses to live in the ocean, just like gasses to live in the ocean, just like we need oxygen in the air to breathe.we need oxygen in the air to breathe.

• Oxygen and carbon dioxide are both Oxygen and carbon dioxide are both dissolved in salt water as they are in dissolved in salt water as they are in air.air.

Other Ocean Properties –Other Ocean Properties –Changes in DepthChanges in Depth• Decreasing Decreasing Temperatures – as Temperatures – as you go deeper intoyou go deeper intothe ocean, you losethe ocean, you losethe sunlight. When the sunlight. When that happens the that happens the temperature temperature decreases asdecreases asyou go towards theyou go towards thebottom of the ocean.bottom of the ocean.

Other Ocean Properties –Other Ocean Properties –Pressure ChangesPressure Changes

• Pressure Increases – the pressure also Pressure Increases – the pressure also gets stronger as you go towards the gets stronger as you go towards the bottom of the ocean.bottom of the ocean.

• This increase in pressure actually makes This increase in pressure actually makes the temperature get hotter – just the temperature get hotter – just slightly.slightly.

Therefore, even as you go to the bottom Therefore, even as you go to the bottom of the ocean, where there is absolutely of the ocean, where there is absolutely no sunlight, the water does not reach no sunlight, the water does not reach freezing – it actually levels off at 4 C.freezing – it actually levels off at 4 C.

Section 12-3 QuestionsSection 12-3 Questions

1.1. What is salinity? What is the average What is salinity? What is the average salinity of the ocean?salinity of the ocean?

2.2. Describe one factor that increases the Describe one factor that increases the salinity of seawater and one factor that salinity of seawater and one factor that decreases its salinity.decreases its salinity.

3.3. Would you expect the seawater just Would you expect the seawater just below the floating ice in the Artic Ocean below the floating ice in the Artic Ocean to be higher or lower in salinity that the to be higher or lower in salinity that the water in the deepest part of the ocean?water in the deepest part of the ocean?

4.4. Where would you find the warmest ocean Where would you find the warmest ocean temperatures on Earth?temperatures on Earth?

Section 12-3 Questions, Section 12-3 Questions, ContinuedContinued

5. How do temperature and pressure 5. How do temperature and pressure change as you go towards the change as you go towards the bottom of the ocean?bottom of the ocean?

Answer all questions in the margin or Answer all questions in the margin or in your notebook on page ____.in your notebook on page ____.