Water And Oceanography

The Chemical Properties of Sea Water

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"The Chemical Properties of Sea Water"
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Recent scientific discoveries revealed the presence of vast frozen reserves of water around the Martian Polar Regions, and these appear to be showing signs of melting. Irrespective of this amazing discovery, it is only this small blue-green planet of ours that we know for certain has vast bodies of water in liquid form covering over 70% of the surface. The mighty seas and oceans that separate the continents remain one of the least explored and understood frontiers that may yet reveal secrets that will change the course of human development.

What we do know and understand with a respectable degree of certainty is the chemical composition and variations that characterise salt-water seas and oceans. Salts are dissolved chemicals released from rocks by erosion and weathering, and transported by streams and rivers to oceans and seas. These salts are primarily from six elements and compounds:

Calcium and

The proportional mix of these salts is relatively constant however the amount of water in the mixture changes and varies with temperature, region and as a result of evaporation (loss) and precipitation (rain). Of these six salts, the significant proportional content consists of 55.03% chlorine, 30.59% sodium, 7.68% sulphur, 3.68% magnesium, 1.18% calcium and 1.11% Potassium. The remaining 0.73% comprises trace amounts of bromide, borate, bicarbonate, strontium, and fluoride.

Seawater density and salinity increases with decreasing temperature and with depth where the highest densities are the result of pressure. Freezing temperature of seawater is 1.9oC at a salinity of 35 parts per thousand. This freezing point will vary depending on the concentration of salts.

In addition to the dissolved salts, seawater contains small amounts of dissolved gasses, including nitrogen, oxygen, carbon dioxide (in the form of bicarbonate HCO3), argon, helium, and neon.

With continuing advances in science and technology, it may be possible for explorers to unlock new and exciting secrets, particularly in deep unexplored areas of our ocean floors. The chemical properties described above represent much of our limited knowledge of our oceans and seas. Who can possibly know what new discoveries are locked in the depths and vast spaces occupying 70% of our planet.

More about this author: Ian Loft

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