Distance phylogram of Proteobacteria partial SSU rRNA gene sequences (approximately 800 bp). Bootstrap values are based on 1,000 replicates and are shown for branches with bootstrap support of >50%. Selected OTUs from this study as well as FRC isolate sequences are in bold, and numbers in parentheses indicate the number of clones belonging to that OTU from sediments FB064, FB067, and FB066, respectively. Accession numbers of sequences from GenBank are in parentheses.