Movement of Motile Bacteria in Unsaturated Porous Media
Abstract
Very few studies address bacterial movement in unsaturated porous media. We studied the ability of motile bacteria to colonize unsaturated porous media columns in 1 mm-diameter sand under static (i.e., no flow) conditions to better understand non-advective mechanisms of microbial movement. Two mechanisms of movement were found to occur at both 5% and 20% volumetric water content. In the absence of an added energy source, cells moved several centimeters in less than 10 minutes via a chemical-physical process. In the presence of an added energy source throughout the column, this initial movement was followed by a motility-driven colonization that proceeded at rates of approximately 10 micrometers per minute. Both mechanisms of movement were controlled by volumetric water content with movement greater at 20% than at 5%, and no movement detected at 1.3%. We are modeling these processes using equations that account for the tortuosity of diffusion paths in partially saturated porous media.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2001
- Bibcode:
- 2001AGUFM.H42E..02B
- Keywords:
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- 0400 BIOGEOSCIENCES;
- 1875 Unsaturated zone;
- 4805 Biogeochemical cycles (1615)