Water and Weather

Chapter Seven: Oceans 7.1 Introduction to Oceans 7.2 Waves 7.3 Shallow Marine Environments 7.4 The Ocean Floor

Investigation 7A How do temperature and salinity cause ocean layering? Global Winds and Ocean Currents

7.1 Introduction to Oceans Ocean water is about 3.5 percent salt. 97% of Earth’s water is in oceans. Only 3% is freshwater. The word salinity is a measure of the dissolved salts in water. Most of the salt in ocean water is sodium chloride.

7.1 Introduction to Oceans In some places, special ponds called salt evaporation ponds harvest salt from the ocean.

7.1 Introduction to Oceans The salt in the oceans comes from: –minerals in the ocean floor –gases released by volcanoes, and –rivers that carry dissolved minerals out to sea.

Can you name Earth’s five oceans?

7.1 Importance of oceans Oceans are an important source of water for the water cycle. Oceans spread energy and heat from the hot equator to the colder poles. Phytoplankton produce most of the oxygen in the atmosphere.

7.1 Earth’s energy The oceans are able to store heat energy. The water on Earth prevents the planet from getting too hot or too cold.

7.1 Oceans and Earth’s climate The climates on the coastline are milder than they are inland because ocean-warmed air masses move over the oceans toward the land.

7.1 Surface currents and gyres Heat energy is spread throughout Earth by ocean currents Surface ocean currents are caused by wind & temperature variations The Gulf Stream is a surface ocean current that is part of the North Atlantic Gyre Gyres spin clockwise in the Northern Hemisphere due to the Coriolis Effect

7.1 Oceans and Earth’s climate Deep ocean currents move below the surface of the ocean. They are slower than surface ocean currents.

7.1 Deep Ocean Currents Deep ocean currents are caused by differences in temperature and salinity Thermohaline is another name for deep ocean currents Salinity, temperature, and rate of evaporation all affect the density of seawater. Denser water causes deep ocean currents.