Ocean Water

Major Ocean Surface Currents

• North Pacific: North Equatorial, Japan, Oya Siwo, Kamchatka, Alaska, California, South Equatorial, Counter Equatorial
• South Pacific: East Australian, Humboldt
• North Atlantic: Florida, North Equatorial, Gulf Stream, North Atlantic, Labrador, Greenland, Canary, Equatorial Counter
• South Atlantic: Brazil, Falkland, South Equatorial, Benguela
• Indian: Western Australian, North Equatorial, Equatorial Counter, South Equatorial, Aguilas
• Arctic Region West Wind Drift
• Other: El Niño, Monsoon

Factors That Affect Currents

1. Primary: These determine the starting of water to move. They include thermal expansion and contraction, the stress of wind blowing over the water, and density differences.

2. Secondary: These influence the direction and the nature of the flow. They include the Coriolus effect, gravity, friction, and the shape of the ocean basin.

3. Coriolus Effect: Anything moving across the globe appears to curve from its initial path. In the Northern Hemisphere, the curve is clockwise. In the Southern Hemisphere, the curve is counterclockwise. The earth is widest at the equator. It becomes narrower toward each pole. Regardless of the location of any given points on the earth, they all take the same time to make a complete rotation. The closer to the equator the point, the farther the distance to be completed. Thus, a point on the equator will move faster than points north or south. Points near the poles move the slowest.

Tides

Diunal tides:

Diunal tides are one high tide and one low tide in one day. Semidiurnal tides are two high tides and two low tides in one day. Mixed tides are those that occur when successive high tides or low tides are of significantly different heights.

Meteorological tides:

Meteorological tides are changes in the water level caused by the weather. Storm surges, seiches, and tsunamis are examples. The term tidal wave refers to actual tides and not to the popular image of great waves caused by storms and earthquakes.

Neap tides:

Neap tides occur at two-week intervals when the sun, the Earth, and the moon form a right angle.

Spring tides:

Spring tides are caused by the linear alignment of the sun, the Earth, and the moon, occurring at two-week intervals at full moon and new moon.

Tidal bores:

Tidal bores form in some inlets and rivers that are exposed to great tidal fluctation. They are steep waves moving upstream, generated by the action of the tide crest in the enclosed area of the river mouth. They are common in the Bay of Fundy, the Amazon River, the Ganges River delta, the Severn River, and some rivers in China.

Tidal current:

A tidal current is the flow of water into or out of bays and harbours. A flood current is the rushing of water, caused by a tide crest, into a closed area. An ebb current is the rushing out by water as the sea level falls.

Tides:

Tides are periodic short-term changes in the height of the ocean surface at a particular place, caused by a combination of the gravitational forces of the moon and the sun and the motion of the Earth.

Constituents of Seawater Salinity

Forchhammer’s Principle (or, Principle of Constant Proportions), formulated in 1865, states that although the total amount of salinity might vary between samples, the ratio of major salts in samples of seawater from many locations is constant.

In this list of seawater constituents, the numbers represent the concentration in parts per thousand, parts per million, and parts per billion.

Parts per Thousand		Parts per Million		Parts per Billion
Oxygen Hydrogen Chloride Sodium Sulfate Magnesium Calcium Potassium Bicarbonate	857.8 107.2 18.98 10.556 2.649 1.272 0.4 0.38 0.14	Bromine Strontium Boron Silicon Fluorine	65   8 4 3 1	Nitrogen Lithium Phosphorus Iodine Zinc Iron Aluminum Manganese Lead Mercury Gold	300 170 70 50 10 10 10 2 0.04 0.03 0.000004