FIG. 3.

Percentage of total (DAPI-stained) cells hybridizing with fluorescent probes Arch915 (Archaea), EUB338 (Bacteria), Rotcl1 (Methanosaeta concilii), MX825 (Methanosaetaceae), and MG1200 (Methanomicrobiaceae) in water samples recovered in September 2001 and October 2002 (i.e., before and after the PPT series) and aquifer material samples recovered in October 2002. Error bars indicate one standard deviation. Percentages of total cells hybridizing with MB1174, MS1414, and Rotcl2 were below the detection limit (1% of total cells).