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A pressure-sensitive nitrogen capsule known commonly as a "widget" allows nitrogen-charged beers to be packaged in cans and bottles. [91] [92] Nitrogen tanks are also replacing carbon dioxide as the main power source for paintball guns. Nitrogen must be kept at a higher pressure than CO 2, making N 2 tanks heavier and more expensive. [93]
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]
Nitrogen leaching occurs when nitrogen compounds, primarily nitrates, move through the soil profile and enter groundwater, potentially contaminating drinking water sources. [2] To mitigate these environmental impacts, various nitrogen management strategies are employed in agriculture.
This process produced a waste known as 'foul lime'. [6] Later the bog iron process supplemented the dry lime. Although the overall compositions of both spent oxide and foul lime are similar, with 6% cyanides and 36-60% free sulfur, [ 4 ] the foul lime is far easier to dispose of.
A simplified food web illustrating a three-trophic food chain (producers-herbivores-carnivores) linked to decomposers. The movement of mineral nutrients through the food chain, into the mineral nutrient pool, and back into the trophic system illustrates ecological recycling. The movement of energy, in contrast, is unidirectional and noncyclic.
Most biological nitrogen fixation occurs by the activity of molybdenum (Mo)-nitrogenase, found in a wide variety of bacteria and some Archaea. Mo-nitrogenase is a complex two-component enzyme that has multiple metal-containing prosthetic groups. [22] An example of free-living bacteria is Azotobacter.
Nitrous oxide (N 2 O), better known as laughing gas, is made by thermal decomposition of molten ammonium nitrate at 250 °C. This is a redox reaction and thus nitric oxide and nitrogen are also produced as byproducts. It is mostly used as a propellant and aerating agent for sprayed canned whipped cream, and was formerly commonly used as an ...
Nitrogen is plentiful in the Earth's atmosphere, and a number of commercially-important agricultural plants engage in nitrogen fixation (conversion of atmospheric nitrogen to a biologically useful form). However, plants mostly receive their nitrogen through the soil, where it is already converted in biological useful form.