Ocean Water Ch. 15

What percent of the Earth’s surface is covered by Oceans? 70%!

Earth has four Oceans

Which one is the largest? Covers 30% of surface of the Earth

Which one has the longest distance North to South?

Which one is mostly in the Southern Hemisphere?

Which one is the smallest? And mostly in the Northern Hemisphere

Ocean water is a mixture of gases and solids dissolved in water 4% dissolved elements: Cl, Na, Mg S, Ca, K 96% PURE WATER

Salinity A measure of dissolved solids in sea water Number of grams of dissolved salts in 1 kilogram of water Evaporation and freezing increases salinity

Salinity with depth:

What two substances are the most abundant in Ocean Water? Chloride Sodium

Salts and other materials in ocean water come from: Volcanic activity in oceans Erosion of land areas by rivers Wave action along the shoreline

Density of Ocean Water: Density is the mass of a substance per unit volume

Two factors affect density 1. Salinity - Dissolved solids make ocean water more dense than fresh water 2. Temperature - Cold water is more dense than warm water

Most abundant gases dissolved in ocean water: Nitrogen (N2) Carbon Dioxide (CO2) Oxygen (O2)

CO2 dissolves most easily Cold water holds more dissolved gases Warm water holds less dissolved gases Think of a pot of water on the stove – what is coming out as the temperature rises??? GASES! (oxygen) The warmer the water, the less gas it holds!

The dissolved gases are recycled back into the air The dissolved solids do not leave, they are used by living things in the sea.

Temperature of Ocean Water Ocean water has ability to absorb sunlight which heats the water

Layering of water by temperature:

Surface zone (mixed layer): Water temp higher at surface because of direct sunlight Waves and currents mix surface water and transfers heat downwards Extends 100-400 meters Warmer at equator than at poles Only place where enough light is present to grow marine plants

Thermocline: Zone of rapid temperature change Warmer water on top of layer Colder, denser on bottom of layer

Area of very cold water that Deep zone: Area of very cold water that extends 1000-4000 meters

COLOR of the Ocean The color of the ocean is determined by the way it absorbs or reflects sunlight. Much of the sunlight penetrates the surface of the ocean and is absorbed by the water.

light are the last color Blue wavelengths of light are the last color to be absorbed

COLOR of the Ocean In clear ocean water, blue light can penetrate up to 100 m before being absorbed. Until it is absorbed, it is reflected and makes the upper layers of ocean water appear BLUE.

At times it will look like other colors depending on what particles are in the water (ex. rocks, animals, etc.) No wavelength of light can penetrate beyond 200 meters, so beyond that it is DARK.

Upwelling process in which surface water moves farther out into the ocean and deep water moves upward to replace the surface water

Observe how upwelling occurs.