High abundance of JS-1- and Chloroflexi-related Bacteria in deeply buried marine sediments revealed by quantitative, real-time PCR


  • Editor: Patricia Sobecky

Correspondence: Anna Blazejak, Bundesanstalt für Geowissenschaften und Rohstoffe, Stilleweg 2, 30655 Hannover, Germany. Tel.: +49 0 511 643 3103; fax: +49 0 511 643 2304; e-mail: Anna.Blazejak@gmx.de


Sequences of members of the bacterial candidate division JS-1 and the classes Anaerolineae and Caldilineae of the phylum Chloroflexi are frequently found in 16S rRNA gene clone libraries obtained from marine sediments. Using a newly designed quantitative, real-time PCR assay, these bacterial groups were jointly quantified in samples from near-surface and deeply buried marine sediments from the Peru margin, the Black Sea, and a forearc basin off the island of Sumatra. In near-surface sediments, sequences of the JS-1 as well as Anaerolineae- and Caldilineae-related Bacteria were quantified with significantly lower 16S rRNA gene copy numbers than the sequences of total Bacteria. In contrast, in deeply buried sediments below approximately 1 m depth, similar quantities of the 16S rRNA gene copies of these specific groups and Bacteria were found. This finding indicates that JS-1 and Anaerolineae- and Caldilineae-related Bacteria might dominate the bacterial community in deeply buried marine sediments and thus seem to play an important ecological role in the deep biosphere.