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Chapter 18 Ocean Motion. Section 18-1 Ocean Water Notes Guide. Water Distrubution. Importance of Oceans. Oceans are important sources of food, energy , and minerals . -Energy sources such as oil , and natural gas are found beneath the ocean floor.
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Chapter 18 Ocean Motion Section 18-1 Ocean Water Notes Guide
Importance of Oceans • Oceans are important sources of food, energy, and minerals. -Energy sources such as oil, and natural gas are found beneath the ocean floor. - Copper and gold are mineral resources that are mined in shallow waters. - One-third of the world’s table salt is extracted from seawater by the process of evaporation. -Millions of tons of oil, coal, and grains are shipped over the oceans each year.
Origin of the Oceans • When the Earth was young, its surface was much more volcanically active than it is today. • When volcanoes erupt they give off lava, ash, water vapor, carbon dioxide, and other gases. • The water vapor was stored in Earth’s atmosphere, until it cooled enough to condense and into storm clouds. • Rains begin to fall, and the water filled low areas on the Earth called basins. • 70 % of Earth’s surface is covered by ocean water.
Composition of the Oceans • Ocean water contains dissolved gases such as oxygen, carbon dioxide, and nitrogen. -Oxygen is needed by organisms for respiration. -Oxygen enters the oceans from the atmosphere and from organisms that photosynthesize. -Carbon dioxide enters the ocean from the atmosphere and from organisms when they respire. -Nitrogen comes from the atmosphere.
Composition of the Oceans Continued… • Ocean water contains many dissolves salts. -Chloride and sodium are some of the ions in seawater. -These ions come from rocks that are dissolved slowly by rivers and groundwater and are carried to the ocean. -Erupting volcanoes add other ions. • Many other ions are dissolved in seawater.
Composition of OceansContinued… • When seawater evaporates, the ions combine to form salts. -Sodium and chloride ions combine to form halite, which gives the ocean it’s salty taste. Salinity is the measure of amount of salts dissolved in seawater. • It is measures in grams of dissolved salts per kilogram of seawater. • One kilogram of seawater contains 35 g of dissolved salts or 3.5 percent. • This proportion has stayed constant for hundreds of millions of years.
Removal of Elements • The ocean is in a steady state-elements are added to the oceans at the same rate that they are removed. • Dissolved salts precipitate out of ocean water and become part of the sediment. • Marine organisms use dissolved salts to make body parts. - Some remove calcium from the water to make bones. - Some use dissolved calcium to form shells, like oysters. -Calcium and silicon are removed more quickly from seawater than other elements.
Desalination • Salt can be removed from ocean water by the process of desalination. • As water evaporates, salt is left behind. • Scientists are working on technology to remove salt from seawater to make it drinkable. • Desalination plants use several methods to remove salt from the seawater to obtain freshwater for drinking.