CRENARCHAEOTA IN LAKE MICHIGAN SEDIMENT

RNA from Lake Michigan sediment was hybridized with a DNA probe for ar chaeal 16S rRNA. There was a peak of archaeal rRNA abundance in the ox ic zone and another immediately below it. Six contributing species wer e identified by PCR amplification of extracted DNA with primers specif ic for archaeal rDNA: two related to Methanosarcina acetivorans and fo ur related to marine crenarchaeotal sequences. rRNA quantification usi ng a DNA probe specific for this crenarchaeotal assemblage showed it i s most abundant in the oxic zone, where it accounts for about 10% of t otal archaeal rRNA.