Chemical and Physical Features of the Ocean

Water - the chemical features You probably know water's chemical description is H2O. The hydrogen atoms are "attached" to one side of the oxygen atom, resulting in a water molecule having a positive charge on the side where the hydrogen atoms are and a negative charge on the other side, where the oxygen atom is. The bonds joining atoms in a water molecule are said to be polar covalent. Since opposite electrical charges attract, water molecules tend to attract each other, making water kind of "sticky."

Picture of a water molecule

Water is called the universal solvent because it dissolves more substances than any other liquid. This means that wherever water goes, either through the ground or through our bodies, it takes along valuable chemicals, minerals, gases, and nutrients.

Water - the physical features Water is unique in that it is the only natural substance that is found in all three states - liquid, solid (ice), and gas (steam) -- at the temperatures normally found on Earth. Earth's water is constantly interacting, changing, and in movement

Water freezes at 32° Fahrenheit (F) and boils at 212° F. In fact, water's freezing and boiling points are the baseline with which temperature is measured: 0° on the Celsius scale is water's freezing point, and 100° is water's boiling point. Water is unusual in that the solid form, ice, is less dense than the liquid form, which is why ice floats.

Water possesses a high specific heat index. This means that water can absorb a lot of heat before it begins to get hot. The high specific heat index of water also helps regulate the rate at which air changes temperature, which is why the temperature change between seasons is gradual rather than sudden, especially near the oceans.

Wind Patterns The trade winds are a pattern of wind that are found in bands around the Earth's equatorial region. The trade winds are the prevailing winds in the tropics, blowing from the high-pressure area in the horse latitudes towards the low-pressure area around the equator. The trade winds blow predominantly from the northeast in the northern hemisphere and from the southeast in the southern hemisphere.

Global Ocean Circulation Ocean circulation is the large scale movement of waters in the ocean basins. Winds drive surface circulation, and the cooling and sinking of waters in the polar regions drive deep circulation.

Coriolis Effect Due to the rotation of the earth, currents are deflected to the right in the northern hemisphere and to the left in the southern hemisphere.

Surface circulation carries the warm upper waters pole-ward from the tropics. Heat is released along the way from the waters to the atmosphere. Surface circulation also carries the cooler waters from the poles toward the tropics.

This is what controls the weather

Underwater circulation As opposed to wind-driven currents the thermohaline circulation is that part of the ocean circulation which is driven by density differences. Sea water density depends on temperature and salinity, hence the name thermohaline.

Three - layered ocean Due to density differences the ocean is divided in to three layers Surface layer (mixed layer) – about 100 -200 meters thick Intermediate layer – from the bottom of the surface layer to about 1000 meters Deep layer – from the intermediate to the bottom

The thermohaline circulation consists of: Deep water formation: the sinking of water masses. Deep water formation takes place in a few localized areas: the Greenland-Norwegian Sea, the Labrador Sea, the Mediteranean Sea, the Wedell Sea, the Ross Sea. Spreading of deep waters mainly as deep western boundary currents Upwelling of deep waters- It is thought to take place mainly in the Antarctic Circumpolar Current region, possibly aided by the wind.

The salinity and temperature differences arise from heating/cooling at the sea surface and from the surface freshwater fluxes (evaporation and sea ice formation enhance salinity; precipitation, runoff and ice-melt decrease salinity).

Tides Tides are the cyclic rising and falling of Earth's ocean surface caused by the tidal forces of the Moon and the Sun acting on the oceans.

Reason for tides The gravitational attraction of the moon causes the oceans to bulge out in the direction of the moon. Another bulge occurs on the opposite side due to centripetal force. Tides are created because the Earth and the moon are attracted to each other, just like magnets are attracted to each other.

The moon tries to pull at anything on the Earth to bring it closer The moon tries to pull at anything on the Earth to bring it closer. But, the Earth is able to hold onto everything except the water. Since the water is always moving, the Earth cannot hold onto it, and the moon is able to pull at it. As the moon travels around the earth and as they, together, travel around the sun, the combined gravitational forces cause the world's oceans to rise and fall. Since the earth is rotating while this is happening, two tides occur each day. The ocean is constantly moving from high tide to low tide, and then back to high tide. There is about 12 hours and 25 minutes between the two high tides

Two types of tides

Spring tides When the moon is full or new, the gravitational pull of the moon and sun are combined. At these times, the high tides are very high and the low tides are very low. They occur when the Earth, the Sun, and the Moon are in a line. The gravitational forces of the Moon and the Sun both contribute to the tides.

Neap Tides During the moon's quarter phases the sun and moon work at right angles, causing the bulges to cancel each other. The result is a smaller difference between high and low tides

Bay of Fundy

Waves The wind not only drives surface currents, it causes waves. Highest part of wave – crest Lowest part of wave - trough Size of wave – height (measured from trough to crest) Distance between waves – wavelength Time it takes to go by a given point – period Distance over water that wind travels – fetch

Fetch Wave height is a function of fetch and wind strength. Around Antarctica, the wind is able to create large waves because there is unlimited fetch.

Some waves undergo a phenomenon called "breaking" Some waves undergo a phenomenon called "breaking". A breaking wave is one whose base can no longer support its top, causing it to collapse. A wave breaks when it runs into shallow water, or when two wave systems oppose and combine forces.

I love waves