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The nitrogen cycle is an important process in the ocean as well. While the overall cycle is similar, there are different players [40] and modes of transfer for nitrogen in the ocean. Nitrogen enters the water through the precipitation, runoff, or as N 2 from the atmosphere. Nitrogen cannot be utilized by phytoplankton as N
Utilizing a large amount of metabolic energy and the enzyme nitrogenase, some bacteria and cyanobacteria convert atmospheric N 2 to NH 3, a process known as biological nitrogen fixation (BNF). [4] The anthropogenic analogue to BNF is the Haber-Bosch process, in which H 2 is reacted with atmospheric N 2 at high temperatures and pressures to ...
Nutrient pollution, a form of water pollution, refers to contamination by excessive inputs of nutrients. It is a primary cause of eutrophication of surface waters (lakes, rivers and coastal waters ), in which excess nutrients, usually nitrogen or phosphorus , stimulate algal growth. [ 1 ]
Reactive nitrogen ("Nr"), also known as fixed nitrogen [1], refers to all forms of nitrogen present in the environment except for molecular nitrogen (N 2 ). [ 2 ] While nitrogen is an essential element for life on Earth, molecular nitrogen is comparatively unreactive, and must be converted to other chemical forms via nitrogen fixation before it ...
Inert atmospheres consisting of gases such as argon, nitrogen, or helium are commonly used in chemical reaction chambers and in storage containers for oxygen-or water-sensitive substances, to prevent unwanted reactions of these substances with oxygen or water. [4] Argon is widely used in fluorescence tubes and low energy
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.
Energy flow is a unidirectional and noncyclic pathway, whereas the movement of mineral nutrients is cyclic. Mineral cycles include the carbon cycle , sulfur cycle , nitrogen cycle , water cycle , phosphorus cycle , oxygen cycle , among others that continually recycle along with other mineral nutrients into productive ecological nutrition.
A practical definition of water pollution is: "Water pollution is the addition of substances or energy forms that directly or indirectly alter the nature of the water body in such a manner that negatively affects its legitimate uses." [1]: 6 Water is typically referred to as polluted when it is impaired by anthropogenic contaminants.