Subarctic grasslands are undergoing natural geothermal warming in Iceland. Credit: C: Christina Kaiser

According to a new study by researchers at the Center for Microbiology and Environmental Systems Science (CEMESS) at the University of Vienna, warm soils harbor a greater diversity of active microbes.

the study, published I Advances in sciencerepresents a significant shift in our understanding of how I Affects the global carbon cycle and potential feedback mechanisms on climate. Until now, scientists assumed that higher soil temperatures accelerated the growth of microbes, thereby increasing carbon emissions into the atmosphere.

However, this increased release of carbon is actually caused by the activation of previously dormant bacteria.

“Soil is the largest reservoir on earth. says Andreas Richter, lead author of the study and professor at the Center for Microbiology and Environmental System Science. Microorganisms are silent breaking down this organic matter, and thus releasing it .

As temperatures rise—under a certain scenario More carbon dioxide is thought to be emitted, further accelerating climate change in a process known as the soil-carbon-climate feedback.

“For decades, scientists have assumed that this response is growth-driven. of individual microbial taxa in a warm climate”, explains Richter. In this study, researchers visited a subarctic grassland in Iceland that has undergone more than half a century of geothermal warming, resulting in approx. The soil temperature is higher than the surrounding areas.

By collecting soil pits and using advanced isotope probing techniques, the team identified active bacterial taxa, comparing their growth rates at both ambient and elevated temperatures, the latter 6 °C higher.

“We found that over 50 years of sustained soil warming increased microbial growth at the community level,” says Dennis Metze, Ph.D. student and primary author of the study. “But remarkably, the growth rate of microbes in warm soils was indistinguishable from those at normal temperatures.” The main difference is found in bacterial diversity: warmer soils harbor a more diverse array of active microbial taxa.

Predicting soil microbial activity in future climates

“Understanding the complexities of the response of the soil microbiome to climate change has been a considerable challenge, often making it a ‘black box’ in climate modeling,” added Christina Kaiser, associate professor at the center.

This new finding goes beyond the traditional focus on overall community growth, setting the stage for more accurate predictions of microbial behavior and its subsequent impact on carbon cycling in a changing climate scenario. Insights from this study illuminate diverse microbial responses to warming and are important for predicting the impact of soil microbiomes on future carbon dynamics.

More information:
Dennis Metze et al., Soil Warming Increases the Number of Bacteria That Grow but Not Their Growth Rate, Advances in science (2024). DOI: 10.1126/sciadv.adk6295.

Reference: Global warming found increase in diversity of active soil bacteria (2024, February 23) Retrieved February 23, 2024 from .

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