It is no secret that the presence of humans has left visible scars on this planet. Be it edging out endangered species with our ever-expanding footprint, or the environmental pollution that comes as a result. One could say we have inextricably linked ourselves with pollution. It is in our drinking water, our soil, and our food. So it’s no surprise pollution has become synonymous with a range of medical issues, from hormone disruption to food sensitivities, and even cancer.
But how do we clean up the mess we've made? What if nature already has a solution? What if something exists, perhaps right under our feet, that can do the job better than we can?
This is what James Tiedje, a world-renowned microbiologist and director of the Michigan State University (MSU) Center for Microbial Ecology, is hoping to find in Earth’s Critical Zone.
“The Critical Zone extends from the tops of trees down through the soil to depths up to 700 feet [213 m],” Tiedje said. “This zone supports most life on the planet as it regulates essential processes like soil formation, water cycling and nutrient cycling, which are vital for food production, water quality and ecosystem health. Despite its importance, the deep Critical Zone is a new frontier because it’s a major part of the Earth that is relatively unexplored.”
The research has thus far focused on soils located in Iowa and China, where soil conditions within the Critical Zone are similar. Initial work, however, began in United States’ Yellowstone National Park, where Tiedje and his team made a groundbreaking discovery: a new, never-before-detected microbe, found to be thriving at depths of around 70 feet (21 m).
This microbial phylum, recently named Sysuimicrobiota (formerly CSP1-3), has since been detected in a variety of environments such as hydrothermal vents, temperate grassland soils, and alluvial aquifers. Genetic analysis indicates Sysuimicrobiota's ancestors come from aquatic environments, emerging first in freshwater lakes and hot springs, millions of years before transitioning to life in soil. This transition suggests a long history of adapting to different niches, making Sysuimicrobiota uniquely qualified to survive in oxygen and nutrient-poor environments such as deep soil substrates. Not only are Sysuimicrobiota microbes found to be highly active and globally distributed, but they can be incredibly dominant, comprising up to more than 50% of microbial populations in some communities.
But Sysuimicrobiota’s most impressive feat is its role in scavenging deep-soil pollutants and aiding water purification.
What does this mean? Well, as rainwater flows through topsoil, surface microbes act as a sort of first line of defense, filtering out and consuming essential elements such as carbon, nitrogen, hydrogen and sulfur. The complication is that for this filtration process to be effective, it requires a healthy microbial population. With modern farming, and its use of pesticides and herbicides, surface microbial communities often suffer. Sysuimicrobiota comes in as a second line of defense, sifting what pollutants remain before water reaches deep aquifers. How effective Sysuimicrobiota is at scavenging pollutants, however, is yet to be determined.
“CSP1-3’s physiology, driven by their biochemistry, is different, so there may be some interesting genes of value for other purposes,” Tiedje states. “For example, we don’t know their capacities for metabolizing tough pollutants and, if we could learn that, we can help solve one of the Earth’s most pressing problems.”
In order to better understand Sysuimicrobiota's role in deep soil ecology, Tiedje and his team have set out to culture the phylum in a lab setting – a challenging task, since most microbes resist growth outside their natural environments.
Currently, the team is experimenting with high-temperature growth conditions, such as those found in hot springs, with the hope that cultured samples will allow further study of Sysuimicrobiota’s unique physiology. In turn, this could have broad implications for biogeochemical remediation of groundwater.
While significant progress has been made, more research is needed to gain insight into the phylum's biogeochemical processes, as well as its role in ecological health as a whole. If Sysuimicrobiota is able to metabolize tough pollutants, it could provide novel solutions for clean drinking water worldwide. A critical need in our increasingly polluted world.
This new study was published in the journal Proceedings of the National Academy of Sciences (PNAS) .
Source: MSU Today.
