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Minerals in the Oceans

Minerals in the Oceans. Year 12 Chemistry - Shipwrecks. Minerals in oceans. Oceans contain an average of 3.5% (35 g/L) of salts Colder regions (polar waters) contain less and warmer regions (tropical waters) contain more

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Minerals in the Oceans

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  1. Minerals in the Oceans Year 12 Chemistry - Shipwrecks

  2. Minerals in oceans • Oceans contain an average of 3.5% (35 g/L) of salts • Colder regions (polar waters) contain less and warmer regions (tropical waters) contain more • Salts produce a high level of ions in solutions, making them electrolytes, which allows redox reactions to occur. Electrolyte: a substance which when dissolved in a solvent such as water, or when molten, is able to conduct an electric current during electrolysis The percentage of ions in the oceans

  3. Sources of Minerals Salts from the land The Earth has a significant amount of minerals within soils and rocks that are soluble in water. Rain water seeps into the soil and dissolves these minerals, carrying them via waterways to the oceans. This process is known as leaching. The concentration of particular salts depends on the rocks (e.g. limestone will have high concentrations of Ca and carbonate ions).

  4. Sources of Minerals Hydrothermal vents (“black smokers”) Where tectonic plates beneath the ocean meet and are moving apart, molten material comes into contact with sea water. This sea water becomes superheated and dissolves surrounding minerals which rise into the oceans forming hydrothermal vents. Some minerals precipitate when meeting the cold water, but some stay dissolved and are dispersed in the oceans. Source: www.uic.edu/.../mike/spring2003/lect04.htm

  5. Hydrothermal vents Click here to see a video

  6. Dissolved Gases in the oceans • Seawater also contains small amounts of dissolved gases. • Some of the important atmospheric gases found in seawater include: nitrogen, oxygen, carbon dioxide (in the form of bicarbonate HCO3). Compared to the other atmospheric gases, the amount of carbon dioxide dissolved in saturated seawater is unusually large. Many gases are added to seawater from the atmosphere through the constant stirring of the sea surface by wind and waves. The higher the temp/salinity the less the gases will dissolve. Source: www.lifesciences.napier.ac.uk/.../Ocycle06.htm

  7. Source: http://www.waterencyclopedia.com/Re-St/Sea-Water-Gases-in.html

  8. Dissolved Oxygen Can you explain the oxygen curve above? Answer: O2 is high at the surface due to mixing with surface air and because of photosynthesis carried out by water plants and phytoplankton. These processes decrease with depth and decomposing material that falls due to gravity, consumes O2 as it falls (minimum at approx. 1000m). Ocean currents carry O2 to the depths and as depth increases, temperature decreases and pressure increases. These conditions allow for higher O2 concentrations

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