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The Ocean. Ocean Water (ch. 17.1). We depend on ocean for: Food & resources Acts as barrier between continents. Origin of Oceans. 4 billion years ago, Earth was full of volcanoes that released CO 2 , hydrogen, water vapor, and other gases into atmosphere.
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Ocean Water (ch. 17.1) • We depend on ocean for: • Food & resources • Acts as barrier between continents
Origin of Oceans • 4 billion years ago, Earth was full of volcanoes that released CO2, hydrogen, water vapor, and other gases into atmosphere. • Lots of water vapor built up in the atmosphere, cooled, and condensed into storm clouds. • Oceans were formed when precipitation filled low areas on Earth called basins.
Composition of Ocean • 70% of water on Earth is ocean water. • Salt comes from dissolved elements (Cl, Na) from rocks and minerals in rivers and groundwater. • Salinity- measures the amount of salt dissolved in seawater. • Every 1000 L of ocean water contains 3.5% or 35 L of dissolved salts. • Salinity of ocean remains balanced since substances are being used and brought in.
Ocean Currents (ch. 17.2) • Current- mass movement or flow of ocean water • Surface currents- moves water parallel to Earth’s surface caused by winds. • Only moves upper seawater
Factors that influence surface currents: • Coriolis Effect- spin of Earth deflects water • Continents deflect currents as they hit land • Other factors: • Wind • Gravity • Solar heating
Importance of surface currents: • Warm ocean water comes from equator • Heat moving from warm ocean water transfers energy into atmosphere, thus, influencing and affecting climate. • Waters on west coasts of continents are colder because currents originate from poles. • Currents on eastern coasts of continents originate from the equator.
Upwelling- circulation in the ocean that brings up deep cold water from bottom to surface • Concentrated cold water brings food and nutrients from bottom to top
Density current- dense seawater sinks under less dense seawater.