Lake Mendota was found to have elevated levels of soluble manganese in the oxic portion of the water column as was seen in previous studies in Lake Vanda, an antarctic lake. Some microbes are able to reduce particulate manganese oxides to soluble manganese. Manganese-reducing microbes isolated from Lake Vanda's oxic zone were unexpectedly found to belong to the genus Carnobacteria . We have over ten manganese reducing isolates from the oxic portion of Lake Mendota where soluble manganese was present. Preliminary results indicate that a few of these isolates may also be Carnobacteria .
Additional characterization is underway.
In a further attempt to look for evidence of Carnobacteria in temperate lakes, a 16S ribosomal RNA-based oligonucleotide probe specific to the genus Carnobacteria was developed. Microbial cells were collected onto a filter at each depth sampled in Lake Mendota. We have been extracting nucleic acids from these filters for hybridization studies to ascertain the presence of 16S rRNA and 16S rRNA genes from Carnobacteria .