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Spotted: A new study led by researchers at the University of Delaware has found that concrete is home to a wide number of bacteria. The team, led by researcher Julie Maresca, published their results in the journal of the American Society for Microbiology, demonstrating that even in a harsh concrete habitat, bacterial communities can survive and thrive. Not only that, but they have shown that changes in these communities can give important information on the condition of concrete structures. 

Concrete is a hard, dry, and salty environment with a typical pH of about 12.5, making it about as hospitable as a bottle of bleach. Despite this, a number of hardy species of bacteria, such as psychrobacter, can call concrete home. These communities are, in turn, affected by elements such as time and weather, which also affect the concrete. Among the team’s findings was that bacterial communities within concrete could provide early warning of alkali-silica reactions that degrade concrete but are difficult to detect.  

They also found that bacteria have the potential to provide “biorepair” of concrete, by producing calcium carbonate, which can fill in cracks and pores in concrete. To study the concrete-based bacterial communities, the team created 40 cylinders and placed them on the roof. DNA samples were collected over a two-year period, then sequenced and analysed. 

Maresca explained that before this work, “There was really nothing at all known about microbes in concrete. It’s the most commonly used building material in the world, but we just don’t know anything about what lives in there. It’s [used] in wet environments, sewer systems, bridge pilings and we know that microbes on surfaces can degrade it. But what’s in there and does it do anything? Can it tell us anything?” 

Bacteria are found just about everywhere, and it is increasingly dawning on researchers and innovators alike that these little critters could be quite useful. We have recently covered a number of bacteria-themed innovations, including the use of bacteria to convert copper ions to usable forms, and the use of bacteria to help save coral from ocean warming. 

Written By: Lisa Magloff

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