Tags: Archaea.
Nitrosopumilus maritimus is an extremely common archaeon living in seawater. It is the first member of the Group 1a Crenarchaeota to be isolated in pure culture. Gene sequences suggest that the Group 1a Crenarchaeota are ubiquitous with the oligotrophic surface ocean and can be found in most non-coastal marine waters around the planet. It is one of the smallest living organisms at 0.2 micrometers in diameter. It lives by oxidizing ammonia to nitrite. N.