Properties of Oceans

1. Properties of Oceans Hydrosphere

2. How much of Earth is ocean? • Remember, about 97% of all the water on Earth is ocean water and not readily available for people to use. Visit: http://www.csduroy.qc.ca/EileenGermain/oceans_and_seas/

3. Why is the ocean salty? • The ocean is salty because of dissolved chemicals eroded from the Earth’s crust and washed into the sea: • Solids and gases come from volcanoes. • Particles are dropped into the oceans by winds. • Materials from sediments are deposited on the ocean floor. • These things combine with the ocean water to dissolve (because remember water is the universal solvent) and mix with the other particles in the ocean water.

4. What is salinity? • Salinity (the amount of salt in water) increases through evaporation or freezing of ocean waters. • Salinity decreases when rainfall, runoff, or ice melts and adds water to the ocean. • The average salinity of ocean water is 35 ppm. • ppm stands for parts per million • Salinity levels are much less in coastal water, polar seas (Arctic Ocean), and where rivers empty into the oceans or seas.

5. What is dissolved in Ocean water? • There are many gases dissolved in the ocean. • The major gases are nitrogen, oxygen, and carbon dioxide. • Some of these gases, as you saw on the previous slide, come from sediments and volcanoes. • Other organisms also contribute to the dissolved gases: • Marine plants release oxygen and take in carbon dioxide (same as a plant on land) when it goes through photosynthesis. • Marine animals need oxygen and release carbon dioxide to go through cell respiration (same as land animals). • Cold water and deeper waters hold more gas than warm and shallow waters. • As the atmospheric gas levels rise, so do the levels of the same gases dissolved in the ocean water.

6. Carbon Dioxide in the Ocean • Some carbon dioxide stays a gas. • Other carbon dioxide reacts with • the ocean water to form carbonic acid • carbonates already in the water to form bicarbonates • Bicarbonates removed CO2 from the water. • Marine organisms use the bicarbonate to form calcium carbonate shells. • When these organisms die, some of the bicarbonate is returned to the water, but a lot if settles down to the sea bed.

7. The cycles influenced by the Earth http://science.nasa.gov/earth-science/oceanography/ocean-earth-system

8. How does the ocean contribute to life on Earth? • The ocean can hold and circulate a lot of water, heat and carbon dioxide throughout the Earth (more than the atmosphere). • Remember the water cycle: water is constantly being recycled and transferred to different parts of the Earth. • The ocean and atmosphere work together to form complex weather patterns: • North Atlantic Oscillation • El Nino • The ocean and atmosphere also interact chemically: • Radiation released into our environment

9. http://www.srh.noaa.gov/ama/?n=elnino

10. http://www.newx-forecasts.com/nao.html

11. Heat and the ocean • Also remember specific heat of water is very high, so that means water takes a long time to heat up, but once there, it takes a long time to cool off. • This keeps the air above the ocean warm. When the ocean is warm it can affect the climate up to 3 months beyond the season and keeps the seasons milder than on continents. • This means the warmth from summer heats up the ocean and can last until the end of fall. • Air temperatures all over the world are circulated and regulated by the heat of the oceans.

12. Photic Zone

13. The Photic Zone • Heat from the ocean can be stored in the upper two hundred meters of the photic zone. • The photic zone is a specific amount of water where there is sufficient light for photosynthesis to occur. • The ocean will store and release heat based on the temperature of the water. • Evaporation cools ocean water which cools the atmosphere. This is easiest to see near the equator and hard to observe near the polar regions because of the extreme temperatures.