December 6, 2012
Researchers Find Surprises When Analyzing DNA From Fracking Site
Lee Rannals for redOrbit.com - Your Universe Online
Researchers making a genetic analysis of microbes living at a fracking site have uncovered some surprises.The scientists reported that they found very few genetic biomarkers for archaea, a domain of single-celled species found in high-salt environments and hot springs. Instead, they found many more for species that derive from bacteria.
The team also reported that they found the populations of microbes changed dramatically over a short period of time, with some species perishing during the fracking operation and others becoming more abundant.
One bacterium prospered from the fracking operations, making up 90 percent of the microbial population in fluids taken from the fracked well.
Researchers may never know the exact species of bacteria in the fluids because of the difficulty in replicating the subsurface conditions, said Paula Mouser, assistant professor of civil, environmental and geodetic engineering at Ohio State University and lead author of the study.
“There are millions of microbes that we can detect using biomarkers, but haven´t ever isolated or cultured from these environments before. Most are grouped into loose associations based on shared genetic characteristics–something akin to a human extended family,” Mouser said.
He said that the best the scientists will be able to do is to identify their microbial cousins.
The study tracked the microbe species found in water pumped out of a tropical fracking site over a period of months during its normal operation. The rock at the site was a type of shale known as Marcellus.
Mouser said the real value of the study is the new knowledge it offers on how microbes in fracking fluids compete and survive when the fluids are injected to the deep subsurface.
“This kind of research is important, because everything we learn about subsurface microorganisms helps us understand ecology on Earth´s surface,” she said. “When water samples like this are shared, there is the potential for great discovery–this knowledge could open doors to new technology for improving gas extraction efficiency or for treating flowback fluids from these sites.”
The study was able to take place through a collaboration with the U.S. Department of Energy National Energy Technology Laboratory (NETL) in Pittsburgh. NETL is working with industry to study fracking technologies and provide Mouser's team with water samples donated by an unnamed shale gas operation.
Mouser said the tiny microbes can play a huge role when it comes to energy extraction.
The chemicals that companies pump into the ground to help fracture shale and release petroleum contain carbon, nitrogen and phosphorous. When left unchecked, the microbes in a fracking well can grow and reproduce out of control, possibly clogging the fractures and blocking extraction.
Oil companies know about the microbes, and add biocides to the water to control the population. However, the companies do not know what kinds of microbes live there.
“Our goal is really to understand the physiology of the microbes and their biogeochemical role in the environment, to examine how industry practices influence subsurface microbial life and water quality,” Mouser said.
The researchers identified 40 taxa from water samples taken at the start of the fracking operation sight. Of those identified, only six survived the first few weeks.
Nearly all of the bacteria at the site were classified as "halo-tolerant," similar to bacteria that live in deep saltwater environments.
Mouser hopes the researchers are able to understand how the microbes metabolize fracking fluids. They hope to meld those discoveries with computer models to predict fluid movement from shale formations to groundwater aquifers.