Fig. 3From: Ammonia-oxidizing bacteria and archaea within biofilters of a commercial recirculating marine aquaculture systemNeighbor-joining tree for DNA sequences of amoA genes of ammonia-oxidizing archaea in recirculating aquaculture systems producing hybrid grouper. Numbers to left of nodes indicate bootstrap support for those nodes. The bar shows phylogenetic distance in numbers of nucleotide substitutions per siteBack to article page