The nitrogen cycle is a biogeochemical process encompassing the biologically mediated and abiotic transformations of nitrogen between atmospheric, terrestrial, and aquatic reservoirs, enabling its assimilation into and release from living organisms. Key microbial processes include nitrogen fixation (conversion of N₂ to bioavailable ammonia), nitrification (oxidation of ammonia to nitrite and nitrate), assimilatory and dissimilatory nitrate reduction, ammonification (mineralization of organic nitrogen to ammonium), and denitrification and anammox, which return nitrogen to gaseous forms (N₂, N₂O). This cycle regulates nitrogen availability, constrains primary productivity, and is tightly coupled to carbon and oxygen cycles in ecosystems.
Nitrogen is an important component of the global environment, affecting agriculture, climate, human health, and ecosystems. The role of the nitrogen cycle has become more widely appreciated, yet Earth system models (ESMs) ...
Earth Sciences
Oct 30, 2025
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New research investigating whether nitrogen fertilizer run-off affects marine sponges suggests these animals have a high tolerance to nitrogen, but some species may be better able to cope than others.
Plants & Animals
Oct 13, 2025
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Recently, a research team in the Hefei Institutes of Physical Science of the Chinese Academy of Sciences has revealed that one-time nitrogen (N) application, a labor-saving practice favored by many farmers, increases both ...
Ecology
Sep 25, 2025
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A new study has revealed how tiny microbes in rivers and wetlands across China help clean up excess nitrogen pollution, offering fresh insights into the health of freshwater ecosystems and the global nitrogen cycle.
Ecology
Sep 25, 2025
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Wetland ecosystems play a crucial role in the global nitrogen cycle, helping to reduce nitrogen pollution. While plant diversity is known to influence ecosystem function, the exact mechanisms linking it to nitrogen retention ...
Plants & Animals
Sep 22, 2025
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Soil nutrients support plants, and the animals who consume plants return these nutrients to the soil, creating a nutrient cycle. In a new study published in Ecology, scientists from the Smithsonian's National Zoo and Conservation ...
Plants & Animals
Sep 10, 2025
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125
A new study published in the Journal of Plant Ecology has found that temperate forest tree species, regardless of their root symbiosis with either ectomycorrhizal (ECM) or arbuscular mycorrhizal (AM) fungi, consistently prefer ...
Plants & Animals
Jun 26, 2025
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An interdisciplinary research team involving the Research Institute of Farm Animal Biology (FBN) in Dummerstorf and the Universities of Rostock, Munich and Vienna has discovered that willow leaves have the potential to drastically ...
Ecology
Jun 17, 2025
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At the uppermost reaches of stream networks, headwaters dry up during the summer, then burst back into existence when spring brings rain. These nonperennial headwater streams are individually small, but collectively, they ...
Earth Sciences
Apr 15, 2025
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More than 112 years ago, Fritz Haber and Carl Bosch industrialized a process that could produce ammonia from nitrogen readily available in the air, creating commercially viable chemical fertilizer capable of improving crop ...
Nanomaterials
Aug 22, 2022
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