Tropical soils could be profoundly altered by global warming •

Micro-organisms such as bacteria or fungi play a fundamental role in the health of tropical forest ecosystems, by breaking down dead organic matter and using the carbon it contains or releasing it into the environment as carbon dioxide. of carbon. According to a new study by the University of Leedsglobal warming will most likely lead to a significant decrease in the number of species of microbes living in tropical soils and thus threaten the biodiversity of tropical forests and increase carbon emissions.

Climate models estimate that the tropics could warm by two to five degrees Celsius by the end of the 21st century. In an experiment on the island of Barro Colorado in Panama, researchers warmed five plots in a lowland rainforest to study what would happen if tropical soils were exposed to such predicted levels of warming. After two years, they discovered that the biodiversity of microbes in the heated plots decreased considerably.

“This research challenges us to think differently about how a warmer climate may affect tropical soils, which support some of the world’s richest biodiversity and are a globally important carbon store,” the author said. principal of the study, Andrew Nottingham, forest ecologist at the University of Leeds.

“If the results we’ve seen in just two years are representative of what will happen in the world’s tropical soils, then there will be a major negative impact on the rich ecosystems they support. A major question is whether any of the missing microbes in the heated plots played a key role in soil functioning, as we know that soil diversity is correlated with soil health. There are other likely implications for plants, as tropical rainforests include associations and symbioses between soil microbes and vegetation.

According to Dr Nottingham and his colleagues, changes in the population of microbes in warming soils will most likely affect these associations, potentially rendering many of them impossible. Thus, changes in the below-ground microbial community will lead to major changes in plant communities above ground.

In addition, scientists have also discovered that warming the land will emit more CO2 into the atmosphere, thus further aggravating climate change. “The implications of these findings are alarming – but by demonstrating how sensitive these ecosystems are to global warming, the findings underscore the urgency of conserving these biodiversity- and carbon-rich ecosystems and tightly limiting current warming,” concluded Dr Nottingham.

The study is published in the journal Natural microbiology.

By Andrei Ionescu, Personal editor

Teresa H. Sadler