Microbes
have a remarkable ability to adapt to the extreme conditions in fracking wells.
Scientists led by researchers at Ohio State University found that microbes
consume some of the chemical ingredients commonly used in the fracking process,
creating new compounds which in turn support microbial communities below
ground. The process allows the microbes to survive in very harsh environments
that include very high temperatures, pressures, and salinity.
The
work, based on samples from hydraulically fractured wells in Pennsylvania and
Ohio, helps scientists understand the complex interactions among microbes --
important for understanding the planet's environment and subsurface. The
findings also help scientists understand what is happening in fracking wells
and could offer insight into processes such as corrosion.
The
team studied microbes in fracking fluid from more than a mile and a half below
the ground surface. Researchers measured the metabolic by-products excreted by
the microbes, which can tell scientists what compounds the microbes are
producing, where they are drawing energy from, and what they need to stay
alive.
Using
multiple samples drawn from the two wells over a 10-month period, the team
identified 31 different microbes in fluids produced from hydraulically
fractured shales. The team found that fractured shales contained similar
microbial communities even though they came from wells hundreds of miles apart
in different kinds of shale formations.
The
complex mix -- with some microbes producing compounds that others use or feed
upon -- produces some interesting outcomes. One particularly interesting
compound, glycine betaine, is what allows the microbes to thrive by protecting
them against the high salinity found in the wells. Other microbes can
subsequently degrade the compound to generate more food for the bacteria that
produce methane. Yet another process may produce substances that contribute to
the corrosion of the steel infrastructure in wells.
The
scientists even discovered a new strain of bacteria inside the wells which it
dubbed "Frackibacter."
For
further details see:
Rebecca A. Daly, Mikayla
A. Borton, Michael J. Wilkins, David W. Hoyt, Duncan J. Kountz, Richard A.
Wolfe, Susan A. Welch, Daniel N. Marcus, Ryan V. Trexler, Jean D. MacRae,
Joseph A. Krzycki, David R. Cole, Paula J. Mouser, Kelly C. Wrighton. Microbial metabolisms in a
2.5-km-deep ecosystem created by hydraulic fracturing in shales.Nature
Microbiology, 2016; 1 (10): 16146 DOI:10.1038/NMICROBIOL.2016.146
Posted by Dr. Tim Sandle