Warming earth affects microbial life underground

(Global warming) - Global warming may affect the survival of soil microorganisms, and the consequences are still unknown to soil fertility and erosion.

Researchers at Arizona State University, USA, have discovered for the first time that temperatures determine areas where important microorganisms can thrive - bacteria that play a very important role in formation of topsoil in arid areas. Scientists predict that, within 50 years, global warming can remove some bacteria from their current habitat in the cold US deserts, causing the Unexpected consequences for fertility and soil erosion.

This discovery appeared as a representative on the cover of the June 28 edition of Science magazine.

The international team led by Ferran Garcia-Pichel, a microbiologist, professor of life science at Arizona State University, surveyed the microbial populations living in the surface soil. Scientists collected surface soil samples from the Oregon area until New Mexico, and from Utah to Califfornia and studied the microorganisms in these soil samples based on their DNA sequences.

While there are thousands of microorganisms in a small patch of soil, two types of cyanobacteria - photosynthetic bacteria - are identified as the most common species. Lack of cyanobacteria, other microorganisms in the soil cannot survive, other organisms depend on them for food and energy.

'We wanted to know which species of microorganisms reside in the soil and whether they play a role with geographic distribution at the continent level,' Garcia-Pichel said. Pichel is also the Dean of the Department of Natural Sciences at Arizona State University College. 'To our surprise, where we once thought that the only cyanobacteria could prevail, we found two cyanobacteria that neatly divided the territory between them. We used to think that a species, called Microcoleus vaginatus, is the most important and dominant species, but now we know that Microcoleus steenstrupii, another species, is just as important, especially at warm climates' , he added. While these two species look very similar, M.vaginatus and M.streenstrupii really have no close association. They have evolved to appear the same because their shape and behavior helps them stabilize the soil and form on the soil crust.

Topsoil is important for the degradation of ecosystems on arid lands, as they protect the soil from erosion and contribute to fertile soil by adding carbon and nitrogen to the soil. by decomposing other nutrients from dust particles trapped in the soil.

Temperature affects microbial populations. After reviewing data on soil types and other factors in terms of chemistry, precipitation, climate, weather, and temperature, researchers used a mathematical model that was shows that temperature is the best explanation for the geographic division of the two microorganisms mentioned above. While scientists found the presence of these two species in the study areas, M.vaginatus dominates the topsoil in the cooler deserts and M.steenstrupii is more advantageous in the safer regions. southern desert.'But this is just a correlation , ' explains Garcia-Pichel. ' To demonstrate the role of temperature, we tested forms of microbial culture and confirmed that the temperature actually made a difference - temperature was the factor that kept the two species. bacteria are far apart. The key point here is that temperature will no longer be stable because of global warming. '

In the southwestern United States, where this study takes place, climate models predict temperatures to rise by about one degree every decade. By using our data with current climate models, we can predict that in the next 50 years, cyanobacteria, the types that live better when warmer temperatures will push the micro cold-loving cyanobacteria out of our map. At that time, M.steenstrupii could be completely dominant in the earth's crust everywhere we studied. Unfortunately, we do not know much about this microorganism and what will happen to the ecosystem without the M.vaginatus species, Garcia-Pichel adds. If the actual distribution of bacteria is altered due to rising temperatures, scientists have not anticipated the possible consequences for soil cultivation and erosion.

These bacteria are hundreds of millions of years old and can be found in many places around the globe. Microbial M.vaginatus individuals anywhere on Earth are closely related to each other and are practically indistinguishable genetically between them. In contrast, the individual change in M.steenstrupii is larger, and this is a species with greater genetic diversity and is thought to be an older evolutionary species.

Garcia-Pichel believes that the pattern of temperature distribution found in the United States may be common all over the world and it will not be easy for M.vaginatus to grow fast enough to withstand rising temperatures. .

The research team is calling on climate change researchers to take microbiological studies when considering global warming.

'Our research is not just about desert ecology. This study illustrates that the distribution of microorganisms and their habitat partitions can be affected by global climate change, we all know the effects of changes in post-planting and pets. This study reminds us that we cannot neglect microorganisms in human interest , ' Garcia-Pichel said. The research team is composed of Yevgeniy Marusenko, a graduate student in Arizona Department of Life Sciences and technical researcher Ruth Potrafka. Professor Pilar Mateo and Virginia Loza graduate student, both from the Universidad Autónoma de Madrid contributed to the project as visiting professors. This project is funded by the National Science Foundation's scholarship.