Search results
Results from the WOW.Com Content Network
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.
The chemical element nitrogen is one of the most abundant elements in the universe and can form many compounds. It can take several oxidation states; but the most common oxidation states are -3 and +3. Nitrogen can form nitride and nitrate ions. It also forms a part of nitric acid and nitrate salts.
Alchemists knew nitric acid as aqua fortis (strong water), as well as other nitrogen compounds such as ammonium salts and nitrate salts. The mixture of nitric and hydrochloric acids was known as aqua regia (royal water), celebrated for its ability to dissolve gold, the king of metals. [9]
Solid nitrogen can dissolve 2 mole % helium under pressure in its disordered phases such as the γ-phase. Under higher pressure 9 mol% helium, He can react with ε-nitrogen to form a hexagonal birefringent crystalline van der Waals compound. The unit cell contains 22 nitrogen atoms and 2 helium atoms.
The new nitrogen can come from below the euphotic zone or from outside sources. Outside sources are upwelling from deep water and nitrogen fixation. If the organic matter is eaten, respired, delivered to the water as ammonia, and re-incorporated into organic matter by phytoplankton it is considered recycled/regenerated production.
Bubbling a solution with a high-purity (typically inert) gas can pull out undesired (typically reactive) dissolved gases such as oxygen and carbon dioxide. Nitrogen, argon, helium and other inert gases are commonly used. To maximize this process called sparging, the solution is stirred vigorously and bubbled for a long time.
The dissociation of salts by solvation in a solution, such as water, means the separation of the anions and cations. The salt can be recovered by evaporation of the solvent. An electrolyte refers to a substance that contains free ions and can be used as an electrically conductive medium. Most of the solute does not dissociate in a weak ...
Cyanobacteria can fix nitrogen by accessing atmospheric nitrogen (N 2) that has been dissolved into water and transforming it into nitrogen accessible to other organisms. [26] This higher amount of nitrogen is then able to sustain large algae blooms in oligotrophic waters.