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The solubility of gas obeys Henry's law, that is, the amount of a dissolved gas in a liquid is proportional to its partial pressure. Therefore, placing a solution under reduced pressure makes the dissolved gas less soluble. Sonication and stirring under reduced pressure can usually enhance the efficiency.
However, for aqueous solutions, the Henry's law solubility constant for many species goes through a minimum. For most permanent gases, the minimum is below 120 °C. Often, the smaller the gas molecule (and the lower the gas solubility in water), the lower the temperature of the maximum of the Henry's law constant.
The amount of gas dissolved in a liquid is described by Henry's Law, which indicates that when the pressure of a gas in contact with a liquid is decreased, the amount of that gas dissolved in the liquid will also decrease proportionately. On ascent from a dive, inert gas comes out of solution in a process called "outgassing" or
Measurements of primary productivity in the ocean can be made using this ratio. The concentration of oxygen dissolved in seawater varies according to biological processes (photosynthesis and respiration) as well as physical processes (air-sea gas exchange, temperature and pressure changes, lateral mixing and vertical diffusion).
Water is the medium of the oceans, the medium which carries all the substances and elements involved in the marine biogeochemical cycles. Water as found in nature almost always includes dissolved substances, so water has been described as the "universal solvent" for its ability to dissolve so many substances.
Inert gas such as nitrogen or helium continues to be taken up until the gas dissolved in the diver is in a state of equilibrium with the breathing gas in the diver's lungs, at which point the diver is saturated for that depth and breathing mixture, or the depth, and therefore the pressure, is changed, or the partial pressures of the gases are ...
Warmer water also raises oxygen demand from living organisms; as a result, less oxygen is available for marine life. [40] Studies have shown that oceans have already lost 1-2% of their oxygen since the middle of the 20th century, [41] [42] and model simulations predict a decline of up to 7% in the global ocean O 2 content over the next hundred ...
Once dissolved, distribution of the dissolved gas is by perfusion, where the solvent (blood) is circulated around the diver's body, and by diffusion, where dissolved gas can spread to local regions of lower concentration when there is no bulk flow of the solvent. Given sufficient time at a specific partial pressure in the breathing gas, the ...