Earth's Oceans By: Abby & barbie

71% of the earth's surface is ocean! All of this water makes up the four main oceans.


Salinity- the amount of dissolved solids in a certain amount of liquid.

Thermocline- the layer of ocean water where the temperature drops and the depth increases quicker than the other layers

Water cycle- the movement of water from water sources, then into the air, onto land, into and over the ground, and then back to water sources. This is a continuous process.

How Dud the Oceans Form?

  • A long time ago, it is believed that the continents were all one landmass called Pangaea.
  • As time went on the continents spread apart.
  • We, as Christians, believe that God sent a giant flood and as the continents move(d) apart the flood filled in the spaces and created oceans.

Characteristics of Ocean Water

even though ocean water isn't drinkable, it has other important characteristics.

  • Ocean water is very salty. Or it contains sodium chloride.
  • Salt is continuously added to oceans by the dissolving of minerals on land by streams and rivers.
  • Running water then brings these broken down elements to the ocean.
  • The water in the ocean is still evaporating, but the broken down solids stay.
  • As more water evaporates, the ocean's salinity increases.
  • Salinity is measured as grams of dissolved solids per kilogram

Factors that Effect salinity

  • Coastal water in areas with hot, dry climates= high salinity
  • Coastal water in areas with cool, humid climates= lower salinity
  • This is because in drier areas, less fresh water runs into the ocean, also because the heat increases its evaporation rate.
  • Water movement is another factor that affects ocean salinity.
  • Salinity varies in different parts of the ocean because of variations in evaporation, circulation, and freshwater inflow.

Temperature Zones

  • As the depth of the water increases, the temperature of the ocean water decreases.
  • This doesn't occur gradually from the surface to the bottom.
  • Ocean water is divided into three layers according to temperature.
  • Surface zone- the warm, top layer of oceans water. Sunlight penetrates the top 100 meters of this layer, heating it with solar energy. Currents on the surface mix the hotter water with the cooler water, extending the surface area to 300 meters below sea level.
  • Thermocline- layer of water that extends from 300 meters to 700 meters below sea level. The water temperature drops with increased depth quicker in this layer than it does in the other two. The water is denser and colder in this layer than it is in the surface zone.
  • Deep zone- bottom layer that extends from the base of the thermocline (about 700 meters) to the bottom of the ocean. The average temperature of this layer is 2 degrees Celsius.

surface temperature changes

  • Temperatures in the surface zone vary with latitude and the time of year.
  • Surface temps. range from 1 degree Celsius near the poles to about 24 degrees Celsius near the equator.
  • Ocean areas along the equator receive more sunlight per year than the poles, causing them to be warmer.
  • In most regions the time of year also affects surface-zone temperatures.
  • For instance, the sun's rays in the Northern Hemisphere are more direct during the summer than during the winter. As a result, the surface zone absorbs more heat energy during the summer.
The changes in surface temperatures during the summer and the winter.

The Ocean and the Water Cycle

  • The Ocean is a big and important part of the water cycle because almost all of the earth's water is found in the ocean.

A Global Thermostat

  • The ocean plays a big part of keeping the right conditions for life on Earth.
  • One of the most important things the ocean does is retain and absorb heat from sunlight.
  • This controls the temperatures in the atmosphere.
  • The ocean absorbs and releases heat much slower than dry land does.
  • Life could not exist with these unstable conditions.
  • Also more direct sunlight hits the equator, causing the waters around the equator to be warmer than in higher latitudes.
  • Ocean currents don't just move water, they move the heat it contains too. These currents move the water and it's heat around the earth.
  • This circulation of warm water causes some coastal lands to have warmer climates than they would have without the currents.


Created with images by Photographing Travis - "Ocean" • PublicDomainPictures - "abstract aqua background" • Web Travel Map (WTM) - "Labadee, Haiti" • jtop2007 - "De San Francisco a Cambria (Big Sur)" • Deidre Woollard - "Cambria"

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