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. 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.