Oceans

Four Oceans of Planet Earth Names Names Pacific Pacific Atlantic Atlantic Artic Artic Indian Indian Characteristics Characteristics Largest Largest Closest to us Closest to us Coldest Coldest Smallest Smallest

Ocean Water Chemistry (12-3) Ocean water contains 35 parts of dissolved Ocean water contains 35 parts of dissolved salts for every 1000 parts of water. This creates a body of water that has 3.5% salinity. salts for every 1000 parts of water. This creates a body of water that has 3.5% salinity. The dissolved salts are as follows: The dissolved salts are as follows: - Chloride 55.0%Sodium 30.6% - Sulfate 7.7%Magnesium 3.7% - Calcium 1.2%Potassium 1.1%

How do the dissolved salts get there? Volcanoes release gasses into the atmosphere and they fall into the oceans. Volcanoes release gasses into the atmosphere and they fall into the oceans. Rivers constantly carry and deposit dissolved substances in from the continents. Rivers constantly carry and deposit dissolved substances in from the continents. All dissolved substances are free floating ions, which make water “charged” electrically. That’s why lightning is attracted to it. All dissolved substances are free floating ions, which make water “charged” electrically. That’s why lightning is attracted to it.

So why doesn’t the salinity get higher? As rivers and volcanoes deposit materials, plants and animals take them out for nutrition, to make shells, for their bones. As rivers and volcanoes deposit materials, plants and animals take them out for nutrition, to make shells, for their bones.

How does salinity affect the ocean? Salt water freezes at -2 0 C (fresh water freezes at 0 0 C.) Salt water freezes at -2 0 C (fresh water freezes at 0 0 C.) Salt water is more dense than fresh water, causing objects to be more buoyant in salt water – You can float better in the salty water! Salt water is more dense than fresh water, causing objects to be more buoyant in salt water – You can float better in the salty water! The Dead Sea has the highest salinity on this planet. Which allows this person to “sit” on the ocean water. The Dead Sea has the highest salinity on this planet. Which allows this person to “sit” on the ocean water.

What can cause the salinity rate to change from the 3.5%? Near the surface of the ocean, large amounts of precipitation can lower the salinity. Near the surface of the ocean, large amounts of precipitation can lower the salinity. Near the poles, freezing temperatures create ice, but leaves the salt behind which increases the salinity. Near the poles, freezing temperatures create ice, but leaves the salt behind which increases the salinity. Near the bottom of very large rivers (Amazon and Mississippi) that deposit huge amounts of fresh water from land will decrease the salinity. Near the bottom of very large rivers (Amazon and Mississippi) that deposit huge amounts of fresh water from land will decrease the salinity.

Other Ocean Properties – Water Temperatures Surface water temperatures are different because the temperature of the air is different. Surface water temperatures are different because the temperature of the air is different. Near the poles the surface ocean water temperature is cold, near the equator the surface water temp. is warmer. Near the poles the surface ocean water temperature is cold, near the equator the surface water temp. is warmer. Cold water is more dense so it sinks, and hot water is less dense so it rises, causing a mixing of the water in a very large circular pattern. Cold water is more dense so it sinks, and hot water is less dense so it rises, causing a mixing of the water in a very large circular pattern.

Other Ocean Properties – Gases in the ocean water Ocean organisms need dissolved gasses to live in the ocean, just like we need oxygen in the air to breathe. Ocean organisms need dissolved gasses to live in the ocean, just like we need oxygen in the air to breathe. Oxygen and carbon dioxide are both dissolved in salt water as they are in air. Oxygen and carbon dioxide are both dissolved in salt water as they are in air.

Other Ocean Properties – Changes in Depth Decreasing Decreasing Temperatures – as you go deeper into the ocean, you lose the sunlight. When that happens the temperature decreases as you go towards the bottom of the ocean.

Other Ocean Properties – Pressure Changes Pressure Increases – the pressure also gets stronger as you go towards the bottom of the ocean. Pressure Increases – the pressure also gets stronger as you go towards the bottom of the ocean. This increase in pressure actually makes the temperature get hotter – just slightly. This increase in pressure actually makes the temperature get hotter – just slightly. Therefore, even as you go to the bottom of the ocean, where there is absolutely no sunlight, the water does not reach freezing – it actually levels off at 4 C. Therefore, even as you go to the bottom of the ocean, where there is absolutely no sunlight, the water does not reach freezing – it actually levels off at 4 C.

Section 12-3 Questions 1. What is salinity? What is the average salinity of the ocean? 2. Describe one factor that increases the salinity of seawater and one factor that decreases its salinity. 3. Would you expect the seawater just below the floating ice in the Artic Ocean to be higher or lower in salinity that the water in the deepest part of the ocean? 4. Where would you find the warmest ocean temperatures on Earth?

Section 12-3 Questions, Continued 5. How do temperature and pressure change as you go towards the bottom of the ocean? Answer all questions in the margin or in your notebook on page ____.