Vol. 61, no. 7, p. 2705, column 2, lines 9 to 16: these sentences should read as follows. "These two sequences show 75% identity at the DNA level to the published N. europaea sequence and show 85% identity to each other. Interestingly, the regions that our primers were designed to target show 5 and 3 mismatches with the Nitrosospira sequence and 2 and 2 mismatches with the Nitrosolobus sequence for the forward and reverse primers, respectively." [This corrects the article on p. 2702 in vol. 61.].