Candidatus Nitrosarchaeum limnium BG20 Genome sequencing and assembly

Collected from Surficial sediments beneath a 12-ft water column from Coastal/estuarine sediments (California). Marine â Group 1â Crenarchaeota are among the most abundant organisms on Earth, yet for the last 15 years our understanding of their physiology and biogeochemical function has remained almost entirely speculative, largely because of our inability to cultivate them. However, a combination of metagenomic, molecular, and cultivation studies have recently revealed that a considerable fraction of mesophilic Crenarchaeota may be chemoautotrophic ammonia-oxidizers. Presently, there is only one described ammonia-oxidizing archaeon (AOA) in pure culture, Nitrosopumilus maritimus, isolated from a tropical marine aquarium (Könneke et al., 2005). Thus, it is imperative to obtain additional cultures and genome sequences of â??environmentally-relevantâ?? AOA from marine and estuarine environments, where these organisms likely play a critical role in nitrification. Strain BG20 was isolated from coastal/estuarine sediments and, interestingly, the 16S rRNA sequence of this organism is only 96% identical to that of N. maritimus, suggesting that it likely represents a novel species of mesophilic Crenarchaeota.