Widespread Distribution in Polar Oceans of a 16S rRNA Gene Sequence with Affinity to Nitrosospira-Like Ammonia-Oxidizing Bacteria

We analyzed the phylogenetic compositions of ammonia-oxidizing bacteria of the β subclass of Proteobacteria from 42 Southern Ocean samples. We found a Nitrosospira-like 16S rRNA gene sequence in all 20 samples that yielded PCR products (8 of 30 samples from the Ross Sea and 12 of 12 samples from the Palmer Peninsula). We also found this sequence in Arctic Ocean samples, indicating a transpolar, if not global, distribution; however, slight differences between Arctic and Antarctic sequences may be evidence of polar endemism.