The paper: M. Könneke et al., "Isolation of an autotrophic ammonia-oxidizing marine archaeon," Nature, 437:543-6, 2005. (Cited in 85 papers)
The finding: David Stahl and colleagues from the University of Washington and Woods Hole Oceanographic Institute were investigating nitrification in the Plum Island Sound estuary in Massachusetts, but they could not find the usual nitrifying organisms. "It finally dawned on us that they probably aren't bacteria," says Stahl. Instead, they isolated a marine crenarchaeote and showed that it aerobically oxidizes ammonia to nitrite - the first observation of nitrification in the domain Archaea.
The implication: Stefan Schouten of the Royal Netherlands Institute for Sea Research found the crenarchaeotal nitrifying enzyme to be more abundant than that of bacteria in the North Sea and the Atlantic (PNAS, 103:12317-22, 2006). Schouten says the findings imply "a major role for Archaea in oceanic nitrification."
The application: In 2004, Schouten and others found that ...
