Scientists Identify Extremely Tough Bacterial Species That Thrive Inside... Concrete

Some bacteria can survive in even the most hostile conditions, such as concrete. A new study has proven this. Microbes can survive in this inhospitable material and can thrive.Research shows that bacteria may be able to detect moisture-induced alkalisilica reactions (or concrete cancer) which can lead to structural defects. We might be able to harness bacteria in the future to repair road and bridge damage.Although previous research had shown that bacteria can live in concrete, scientists wanted to examine how these microbes might interact with each other over time.According to Julie Maresca, a microbiologist at the University of Delaware, "There wasn't really anything at all known about microbes within concrete." It's the most widely used building material in the globe, but we don't know much about the life inside.It's found in wet environments, sewer networks, bridge pilings, and we know that microbes can degrade it. But what is it doing there? What can it tell us?Maresca and her coworkers used 40 concrete samples to study the results. Each sample was approximately the same size as a liter (34oz) bottle. Some of the concrete samples were made from a standard mix that is susceptible to alkali-silica reaction, while others used a modified formula to prevent these reactions.Regular monitoring of the roof for two years revealed that the most common bacteria found in DNA analysis of samples was Proteobacteria. Firmicutes and Actinobacteria were the most prevalent. Researchers believe that around 50-60% of the bacteria came from raw materials, particularly gravel.The team noticed that bacterial diversity was declining over time. However, some bacteria types had 'bounces’ as the seasons changed. This could be an indicator that food resources were changing.Concrete samples were used for the study. (University of Delaware)."What are they eating?" Maresca says. It is possible that they are eating dead microbes. Some of them will form spores if there is nothing to eat. Or they may form dormant cells and wait for rain. Then, they eat as much as possible and then go dormant.Although there was no difference in the number of bacteria in both concrete types, some microbes preferred the standard mix. Researchers hope that more research will help them to detect potentially unstable structures by their bacteria before cracks appear.A 2020 US report showed that more than 45,000 bridges in the country's 618.456 were listed as being "poor". This is not the best news if you have a road trip planned. Collapsing concrete can prove fatal, as we have seen.Some bacteria can make calcium carbonate, which is useful for filling concrete cracks and pores. There is hope that these microorganisms might be used to repair buildings and infrastructure. However, that is still a far-fetched possibility.Maresca says that the concrete is not being damaged by microbes. "Microbes don't eat the foundations. They are being used for information, and possibly to aid in repair.The research was published in mSystems.