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NO 3 − may also be denitrified by bacteria, producing N 2, NO x, and N 2 O. Estimated nitrogen surplus (the difference between inorganic and organic fertilizer application, atmospheric deposition, fixation and uptake by crops) for the year 2005 across Europe. Human impact on the nitrogen cycle is diverse.
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] Sources of nutrient pollution include surface runoff from farm fields and pastures, discharges from septic tanks and feedlots , and emissions from combustion.
Soils that receive nitrogen fertilizers can also be damaged. An increase in plant available nitrogen will increase a crop's net primary production, and eventually, soil microbial activity will increase as a result of the larger inputs of nitrogen from fertilizers and carbon compounds through decomposed biomass.
Nitrogen fertilizer can be converted by soil bacteria to nitrous oxide, a greenhouse gas. [56] Nitrous oxide emissions by humans, most of which are from fertilizer, between 2007 and 2016 have been estimated at 7 million tonnes per year, [ 57 ] which is incompatible with limiting global warming to below 2 °C.
Even though nitrogen is a necessary element for life, too much of it in water can have negative effects on aquatic ecosystems and endanger human health. Agricultural runoff, where fertilizers containing nitrogen compounds can seep into rivers, lakes, and groundwater, is one of the main sources of nitrogen in water.
New data from satellites has provided further evidence that the deaths of hundreds of endangered Botswanan elephants were the result of climate change.. A new analysis found that the mass die-off ...
Eutrophication is caused by excessive concentrations of nutrients, most commonly phosphates and nitrates, [11] although this varies with location. Prior to their being phasing out in the 1970's, phosphate-containing detergents contributed to eutrophication. Since then, sewage and agriculture have emerged as the dominant phosphate sources. [12]
A man put to death using nitrogen gas shook and convulsed for minutes on the gurney as Alabama carried out the first-of-its-kind execution that has ignited debate over the humaneness of the method.