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Properties of Ocean Water. Ocean Water Composition. The ocean water is not pure. There are many things that make it unique. Can you think of any? Dissolved gases like Nitrogen and Oxygen which comprise most of the atmosphere also make up a huge portion of the ocean water as well.
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Ocean Water Composition • The ocean water is not pure. There are many things that make it unique. Can you think of any? • Dissolved gases like Nitrogen and Oxygen which comprise most of the atmosphere also make up a huge portion of the ocean water as well. • These gases are released directly into the ocean water from streams and rivers. Some of the gases in ocean water come directly from volcanic eruptions. • Most of the oxygen in the ocean comes from the atmosphere.
Temperature and Dissolved Gases • The temperature of the water affects the amount of gas in the water. • Gases dissolve more readily in cold water. • Gases can return to the atmosphere from the ocean. If the water temperature rises, smaller amounts of gases will remain and the excess gas will be released into the atmosphere.
The Ocean as a Carbon Sink • The oceans dissolve more than sixty times as much carbon as the atmosphere does. Dissolved carbon dioxide may be trapped in the ocean for hundreds or thousands of years. • Because of this ability to dissolve a large amount of carbon dioxide, the ocean is commonly referred to as a carbon sink.
Dissolved Solids • Ocean water is 96.5 percent pure water, or H2O. Dissolved solids make up 3.5 percent of all of the mass in ocean water. These dissolved solids are called sea salts. • Solids dissolved in the oceans are composed of seventy-five different chemicals. The six most abundant of these elements are chlorine, sodium, magnesium, sulfur, calcium, and potassium. • There are also some trace elements left in the water. This means that there is a small amount left. Some of these are gold, zinc, and phosphorus. • Most of the elements come from three main sources. These are volcanic eruption, chemical weathering, and chemical reactions between water and sea-floor rocks.
Salinity of Water (a.k.a salt) • Salinity is a measure of the amount of dissolved salts in a given amount of liquid. • Modern instruments measure the amount of salinity by testing the conductivity of the water. • Salinity is measured in parts. • Precipitation and evaporation affect the salinity of water. About 35 percent of the ocean is salt.
Temperature of Ocean Water • Ocean temperature depends on the depth and location of the surface water within the ocean. • The range of the ocean’s temperatures is affected by the amount of solar energy on a given amount of water space. • For example, in the polar regions the water is significantly cooler because the pack ice which surrounds the earth’s surface is cooler. • Pack ice is a floating layer of ice that completely covers an area of the ocean surface.
The Thermocline and Deep Water • Because the sun can only penetrate the water to within a certain depth, the bottom of the ocean is much cooler than the water at the top. • The thermocline exists becaue the water near the surface becomes less dense as energy from the sun warms the water. This warm water cannot mix easily with the cold water. Thus, a thermocline marks a distinct separation between the two layers. • In deep ocean zones the temperature can be about two degrees cooler. The colder the water is the denser it is. This water controls currents.
Density of Ocean Water What is density? Two different factors affect the density of water. Salinity and temperature affect the density. Dissolved solids which are mainly salts, add mass to the water. The large amount of dissolved solids in the ocean water make it denser than pure fresh water. Ocean water also becomes denser as it becomes colder and more dense as it becomes warmer.
Color of Ocean Water • The color of the ocean is determined by how it reflects and refracts light. Water absorbs most of the lengths, or colors, of visible light. Only the wavelengths tend to be reflected. The reflection of this blue light makes ocean water appear blue. • Some organisms affect the color of water. These organisms are called phytoplankton. Which absorb red and blue light, but reflect green. Since there is a large supply of phytoplankton, the water reflects that color. • The color also indicates the health of the ocean by showing whether or not the plankton are the correct color.
