In-situ biofilm detection in field settings using multichannel seismic

Biofilm aids a variety of geoengineering applications but a general lack of in-situ detection and monitoring methods severely limits its field usage. In this pioneering study, we show that in-situ field detection of biofilm may be possible through multichannel surface seismic. Our study was conducted at a landfill site in Norman, Oklahoma, where an ongoing interaction of a leachate plume with a fluctuating water table has created optimal conditions for biofilm growth. We acquired multichannel seismic data along a 130 m long profile and inverted the ground roll and refractions respectively for S-wave (V-S) and P-wave (V-P) velocity structures of the shallow (0-5 m) subsurface. We find that within similar to 1.2 m-similar to 3.0 m depth, which is the water table fluctuation zone (WTFZ), VS increases by similar to 50% over the background but without any appreciable changes in the V-P. Environmental scanning electron microscopy of soil samples from various depths along a core shows the presence of biofilm exclusively within the WTFZ. A V-S-only increase due to biofilm growth is consistent with laboratory studies of similar nature and can be realized through a mechanistic model where biofilm is simultaneously present in two morphologies: grain-cementing and pore-filling. Our findings open doors to detecting biofilm in a variety of settings such as hyporheic zones and contaminant plume fringe and for a range of purposes from soil remediation to carbon sequestration to detecting life in other planets.

Automated summary

In this pioneering study, the possibility of in-situ field detection of biofilm through multichannel surface seismic was demonstrated. The study revealed unique characteristics of biofilm growth in the water table fluctuation zone (WTFZ) and suggested potential applications in various settings such as soil remediation, carbon sequestration, and the search for life on other planets.