Mireia Bartrons co-authors a study on the effects of climate change on soil carried out in Iceland

Climate change will heat up the air, the sea, but also the soil. Key processes for our survival take place beneath our feet, such as the recycling of organic matter and the fertility of soil. This Monday, the journal Nature Ecology & Evolution is publishing the most comprehensive research carried out to date on the effects of warming the soil in the short and long term. This research was conducted by the ForHot Consortium in Iceland, which was established in 2012 by a group of scientists, who are convinced that Iceland is the best laboratory in Europe for studying global warming.

These scientists include the co-authors of the study Mireia Bartrons, a lecturer and a member of the Aquatic Ecology research group at the University of Vic - Central University of Catalonia (UVic-UCC), Sara Marañón, Jordi Sardans and Albert Gargallo, researchers at the CREAF (Ecological and Forestry Applications Research Centre) and Josep Peñuelas, a researcher at the CREAF and the CSIC (Spanish National Research Council).

During their work, the researchers observed that the ecosystem suffers experiences an overreaction during the first few years of the soil warming: the metabolism of microorganisms speeds up, carbon is released into the atmosphere, and the soil's composition changes. However, in the long term, it reaches a new equilibrium at which point no sudden changes appear to take place: the species of living beings are different or have adapted, and although the concentrations of carbon, nitrogen and organic matter are lower, the ecosystem has reached a new steady state.

The researchers compared the effects of warming on 124 elements in the ecosystem that included various living organisms (plants, communities of microorganisms and fungi) and inert elements (soil composition). According to the research team, one of the strong points of their work is the consortium which they belong to, which consists of scientists studying different variables in the same places, such as microbial communities, soil chemical variables, root biomass, nematodes, vegetation and carbon levels. "The focuses of other research are more limited in scope," says Sara Marañón, a researcher at the CREAF and the co-author of the study.

An area in Iceland shows the short-term and long-term consequences of soil warming       

The research was carried out near Hveragerdi in southwestern Iceland - "a special location because the geothermal activity there causes the soil temperature to rise from 0.5 °C to 40 °C, depending on the distance to the underground hot spots," says Mireia Bartrons, "and this allows us to study how the rise in temperature affects the subarctic ecosystem."

The ages of the temperature gradients in this environment also vary. On the one hand, some soils have evolved with these gradients for over 50 years. On the other, an earthquake in 2008 created new geothermal gradients in other soils. As a result, the researchers were able to compare the effects of rising temperatures on the soil ecosystem in the short term (from 5 to 8 years) and the long-term effects (over 50 years). "Experiments measuring the impact of the temperature of the soil do not usually date back so far, and rarely last longer than 10 years. The most innovative feature of our research is that it enables us to observe changes in ecosystems over the long term, and to find out for the first time about the adaptations that different elements and processes undergo in the ecosystem. That is extremely valuable," say the researchers.

According to Mireia Bartrons, "the key in this research is not to try to extrapolate the specific changes that take place in the various communities of plants, microorganisms and animals in this area to other ecosystems, but instead to identify the elements in an ecosystem that are most useful for predicting the effects of climate change in the long term." Her colleague Sara Marañón adds that "we cannot expect all global warming studies to last for over 50 years. That's why this research provides a framework for understanding the changes that these rising temperatures trigger in the ecosystem. This will make it easier for future research to select the variables that can best predict what will happen in the long term using a short-term analysis."