Figure 1. The effects of the addition of 2,2-dibromo-3-nitriloprorionamide (DBNPA) on the abundance of 16S rRNA gene copies/ml over time in the studied clusters of streams that have either been impacted by hydraulic fracturing (HF+), or unimpacted by hydraulic fracturing (HF-). Figure taken from Campa et al. 2019.
Unconventional oil and gas (UOG) extraction is a method used to allow oil and gas to flow from tight sands that we cannot get to when using the conventional method of drilling. The process consists of drilling down, then horizontally to the point where fracking occurs. Pressurized liquid made up of sand, water, and chemicals cause fractures to the rock below, which causes the fracking process. One of the second most used biocides in the UOG process is 2,2-dibromo-2-nitrilopropionamide (DBNPA). The DBNPA biocide has both toxic and nontoxic properties, so the study performed by Campa and her colleagues strived to understand the response for stream microbial communities to the DBNPA biocide. The 16s rRNA gene copies from LL and NH streams impacted by hydraulic fracturing (HF+) decreased after 7 days of adding the DBNPA biocide, while the EE and WE streams that were un-impacted by hydraulic fracturing (HF-) experienced an increase. The decrease after addition of DBNPA in the HF+ microcosms indicates that the HF+ was sensitive to the biocide. However, in days 56 where the biocide was least present, HF+ had the overall greatest number of gene copies/ml than HF- microcosms. Despite the negative effects that the biocide had in the introduction phase in HF+ microcosms, the numbers of 16s rRNA gene copies show that there is an overall environmental tolerance to high concentrations of DBNPA, meaning that the biocide isn't as effective in controlling complex and dynamic microbial communities.
Original article:
Campa M, Techtmann S, Ladd M, Yan J, Patterson M, Garcia A, et al. (2019). Surface Water Microbial Community Response to the Biocide 2,2-Dibromo-3-Nitrilopropionamide, Used in Unconventional Oil and Gas Extraction. Applied and Environmental Microbiology, 85(21). doi:10.1128/AEM.01336-19
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