Oceans By Gina Wike

Origin & Composition of Ocean Water Oceans affect you regardless of where you live Affects the cost of goods because of shipping costs Some food comes from the ocean .

How the oceans formed 4 billion years ago, water began to accumulate in the atmosphere. As temperatures on Earth cooled, condensation occurred and we had precipitation. Took millions of years for the ocean to form Water filled in low areas known as basins.

Elements in the oceans Oceans contain dissolved elements such as sodium, chlorine, sulfur, magnesium, and calcium.

Elements 2 Places Elements Come from 1. Groundwater dissolves the elements from rocks and then elements such as calcium are carried by rivers to the ocean 2. Erupting volcanoes (sulfur dioxide)

Elements The 2 most abundant elements are sodium (from rivers) and chlorine (from volcanoes) and combine to form salt. (halite) For every 1000 liters of ocean water, there are 35 liters of dissolved salts; 3.5% Salinity is a measure of the amount of solids dissolved in seawater. Salinity has remained constant for millions of years. Desalination is the removal of salt from ocean water to make freshwater.

Ocean Currents Surface & Density

Surface Currents Surface currents only affect the upper 200 meters of water. The Gulf Stream is a surface current which warms the areas it goes by; England’s climate is affected by it. Surface currents are caused by wind; friction between the wind and water cause it to move.

Surface Currents Surface currents are affected by the Coriolis Effect. It causes currents north of the equator to move clockwise and currents south of the equator to move counter-clockwise. Coriolis Effect

Surface Currents & Continents Continents deflect surface currents Currents on the western side of a continent originate in the polar regions and are cold currents; currents on the eastern side of a continent originate in the equatorial region and are warm currents. Surface currents affect the climates of the places they pass by.

Surface Currents Surface ocean currents are generally wind driven and develop their typical clockwise spirals in the northern hemisphere and counter-clockwise rotation in the southern hemisphere. Which ever way the wind blows, the currents will follow the same path. Warm surface currents invariably flow from the tropics to the higher latitudes at the poles. Cold surface currents come from polar and temperate latitudes, and they tend to flow towards the equator.

What Influences Surface Currents? Ocean currents are driven by two forces: the Sun (which causes wind) and the rotation of the Earth. Although wind blowing across the surface of an ocean can produce currents, these currents don’t continue moving in the same direction as the wind. Earth’s rotation causes ocean currents to bend to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This force that does not allow currents to flow in a straight path is called the Coriolis effect.

The Importance of Surface Currents The main importance of surface currents is to distribute the heat from the equator and the coldness from the poles. This “even” distribution of the temperature in the oceans helps to balance the heat budget here and in the atmosphere. The currents also influence the climate of an area. Warm currents keep coastal cities warmer and cold currents keep coastal cities cooler!

Cold Water Currents: California, Canary, Labrador, E. Greenland, Peru, Benguela, W. Australia, Oyashio, Antarctic Circumpolar Warm Water Currents: Alaska, Gulf Stream, Brazil, Agulhas, E. Australia (remember Nemo and the EAC!!), Kurashio, Mozambique, Norwegian

Density Currents A density current is when dense seawater from the poles (which are cold) move toward an area where seawater is less dense-the equator (warm). Dense water sinks and travels toward the equator and less dense water rises and moves toward the poles. Salt makes water more dense.

Upwellings Upwellings occur when cold water from deep in the ocean bring nutrients to the surface.

Upwellings

Upwellings

How Deep Currents Form

Deep Currents Deep currents are found in the deep ocean where there are lots of density differences. The two factors that affect the density of ocean water are temperature and salinity. By decreasing the temperature and increasing the salinity, the density of ocean water increases.

The Movement of Deep Currents Colder, denser water sinks to the ocean floor and eventually rises to replace water leaving in surface currents. This is convection! Convection also induces upwelling along the coastlines of continents. Deep currents move very slow. In fact, the deepest current, Antarctic Bottom Water, takes 750 years to make it from Antarctica to the coastal waters of the equator!

Ocean Water & Tides

Waves Waves are when water rises and falls. Parts of a wave: 1. Trough- lowest point 2. Crest- highest point 3. Wave height- vertical distance between a crest and a trough 4. Wavelength- horizontal distance between 2 crests or 2 troughs

Waves are caused by wind- the bigger the wind, the bigger the wave.

Waves Each particle of water moves around in a circle; the water stays in the same place and the energy moves forward. The water in waves moves in small, circular patterns called orbitals. These orbitals get smaller as you go deeper in the water. Once you reach a depth that is one-half the wavelength, the water is no longer moved by wind.

Wave Movement As waves move toward the shoreline, the water gets shallower. Eventually, the bottom part of the wave stops completely, increasing the wave height. As the waves get taller and taller, they eventually collapse on themselves, and then crash on the shore. This is what is meant by a wave “stubbing its toe”!

Breakers A breaker is when the top part of a wave outruns the bottom and the wave collapses. Gravity pulls water back to the sea.

Tides Waves can be created by the gravitational force the sun, moon, and the Earth. Tides result in the periodic change of the surface level of oceans. Twice a day sea level rises and falls Tidal range is the difference between high tide and low tide.

Tides & Gravity The strength of gravity depends upon the mass of the objects and the distance between them. The Moon’s gravity exerts a strong Earth; the pull is greater on the side facing Earth.

Tides The ocean bulges on the side close to the moon; there is a bulge on the opposite side due to inertia. This is known as HIGH TIDE. LOW TIDES are in the areas where the water is drawn from.

Tides As Earth rotates, areas go through low and high tides. Some places have 2 high and low tides a day (Pacific & Atlantic); other places only once a day.

Tides The timing of tides is determined by the Earth's rotation and the Moon's orbit around the Earth. As the Earth rotates once about its axis in 24 hours, the Moon is moving 1/30th of the way around in its orbit. It takes a given location on Earth about 50 minutes to "catch up with" the orbiting Moon, so a particular tide returns in approximately 24 hours and 50 minutes.

The Sun also affects tides– it can strengthen or weaken them. Sun & Tides The Sun also affects tides– it can strengthen or weaken them.

Spring Tides & Neap tides 2 Types of Tides Spring Tides & Neap tides

Spring Tides Spring tides are when the moon, sun, and earth line up High tides are higher and low tides are lower Happen during the new or full moon phase

Spring Tide

Neap Tides When the moon, sun, and Earth form a right angle High tides are lower and low tides are higher. Happen during the 1st & 3rd quarter