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Methane is a potent greenhouse gas, second only to carbon dioxide in its capacity to trap heat in Earth’s atmosphere for a long time. The gas can originate from lakes and swamps, natural-gas pipelines, deep-sea vents and livestock. Understanding the sources of methane, and how the gas is formed, could give scientists a better understanding of its role in warming the planet.
Now a research team has developed an instrument that can rapidly and precisely analyze samples of environmental methane to determine how the gas was formed. The approach, called tunable infrared laser direct absorption spectroscopy, detects the ratio of methane isotopes, which can provide a “fingerprint” to differentiate between two common origins: microbial, in which microorganisms, typically living in wetlands or the guts of animals, produce methane as a metabolic byproduct; or thermogenic, in which organic matter, buried deep within the Earth, decays to methane at high temperatures.Image credit: Danielle Gruen (edited by Jose-Luis Olivares/MIT)
