Evolution and Future of Earth's Nitrogen Cycle

• Published in: Science (American Association for the Advancement of Science) Vol. 330; no. 6001; pp. 192 - 196
• Main Authors: Canfield, Donald E, Glazer, Alexander N, Falkowski, Paul G
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 08-10-2010; The American Association for the Advancement of Science
• Subjects: Air pollution; Applied sciences; Archaea - genetics; Archaea - metabolism; Atmosphere; Atmospheric chemistry; Atmospherics; Bacteria - genetics; Bacteria - metabolism; Biological Evolution; Chemical Phenomena; Coastal; Crops, Agricultural - growth & development; Crops, Agricultural - metabolism; Earth; Earth sciences; Earth, ocean, space; Ecological and Environmental Phenomena; Economics; Engineering and environment geology. Geothermics; Environmental impact; Eukaryota - genetics; Eukaryota - metabolism; Evolution, Planetary; Exact sciences and technology; Feedback; Forecasting; Geochemistry; Geochemistry: general, methodology, regional studies; Geological time; Human influences; Humans; Microorganisms; Nitrates; Nitrification; Nitrogen; Nitrogen - chemistry; Nitrogen - metabolism; Nitrogen Compounds - chemistry; Nitrogen Compounds - metabolism; Nitrogen cycle; Nitrous oxide; Nitrous oxides; Oceans; Oxidation-Reduction; Oxygen; Pollution; Pollution, environment geology; Quaternary ammonium compounds; REVIEW; Microbial activity; mass balance; biogeochemical cycle; nitrous oxide; reservoirs; nitrites; nitrogen cycle; nitrates; pollution; denitrification; Precambrian; greenhouse gas; agriculture; feedback; coastal zone; flux; Sustainable management; Anthropogenic factor; sea water; eutrophication; continents; Human activity; ocean; transformations; Phanerozoic; fresh water
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1186120

Atmospheric reactions and slow geological processes controlled Earth's earliest nitrogen cycle, and by approximately 2.7 billion years ago, a linked suite of microbial processes evolved to form the modern nitrogen cycle with robust natural feedbacks and controls. Over the past century, however, the development of new agricultural practices to satisfy a growing global demand for food has drastically disrupted the nitrogen cycle. This has led to extensive eutrophication of fresh waters and coastal zones as well as increased inventories of the potent greenhouse gas nitrous oxide (N₂O). Microbial processes will ultimately restore balance to the nitrogen cycle, but the damage done by humans to the nitrogen economy of the planet will persist for decades, possibly centuries, if active intervention and careful management strategies are not initiated.