Ammonia-oxidizing archaea (AOA) typically predominate over ammonia-oxidizing bacteria in marine sediments. We herein present the draft genome sequence of an ammonia-oxidizing archaeon, “
Nitrosopumilus sediminis” AR2, which was enriched in culture from a marine sediment obtained off Svalbard, within the Arctic Circle. The typical genes involved in archaeal ammonia oxidation and carbon fixation necessary for chemolithoautotrophic growth were observed. Interestingly, the AR2 genome sequence was revealed to possess, uniquely among cultivated AOA from marine environments, a capability for urea utilization.