Ocean water is a soup of living organisms, such as fish, plants, and kept along with minerals and dissolved gases. The water from the ocean contains large amounts of dissolved gases, especially nitrogen, carbon dioxide, and oxygen.
The amounts of these gases in the water depend on water depth and temperature. Plants living near the surface of the ocean receive more sunlight than those living deeper in the ocean. As plants grow, they give off oxygen. Therefore, there is more oxygen near the surface of the water.
Gasses dissolve more easily in cold water than in warm water. Therefore, water in colder regions of the world contains larger amounts of dissolved gases.
Would there be more dissolved gases in the water near Florida or in the water near Alaska?
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Both plants and animals depend on the dissolved gases in the ocean water. Tiny living creatures called plankton float near the surface and drift with the currents. The word plankton comes from a German word meaning “drifters.” This is what plankton do, drift as opposed to swim. For the most part they are microscopic and get around with the movements of the ocean currents. They are also typically found at or near the surface of the water. Plantlike plankton called phytoplankton must have oxygen, carbon dioxide, and other dissolved gases and elements to survive. Animal-like plankton called zooplankton feed on phytoplankton. The phytoplankton and the zooplankton depend on each other for survival.
Along with dissolved salts, gasses and living plankton, ocean water also contains sediments that have been washed into the ocean or stirred up from the bottom. These sediments, such as sand particles, bits of shells, and decaying organisms do not dissolve in water.
Ocean water also contains harmful substances such as pollutants that have been dumped in the ocean.
Ocean water is a complex mixture of water, elements, and living things. This mixture provides oxygen and food which supports other living things in the ocean and on the land.