The mystery of Don Juan Pond

摘要

Naturally occurring nitrous oxide, a potent greenhouse gas, is mainly produced by biological processes. So how can it have formed in high concentrations in one of the harshest environments on Earth, a place where attempts at finding life have failed? Writing in Nature Geoscience, Vladimir Samarkin etal. provide the answer: an unexpected abiotic mechanism for nitrous oxide production (V. Samarkin etal. Nature Geosci. doi:10.1038/NGEO847; 2010). The authors report their discoveryrnof nitrous oxide emissions from the soil around Don Juan Pond in Antarctica (pictured), a lake that is so salty it almost never freezes, even in the cold Antarctic winter. Surprisingly, Samarkin and colleagues found that the flux of gas from the lifeless soil was comparable to that of certain tropical soils that teem with microorganisms.