The recent heatwave could be having a more negative effect on soil than previously thought, according to a study involving DNA analysis by the Centre for Ecology & Hydrology.
A new paper, led by the University of Manchester and published in Nature Communications, provides new insight into how a drought alters soil at the microbial level, revealing bacterial networks may not be as resilient to climate change as previously thought.
Extreme weather conditions change vegetation composition and soil moisture, which in turn impact underlying microbial networks. Therefore, climate change could have widespread implications for plants and other vegetation which, in turn, may impact on the wider ecosystem.
Scientists involved in the EU-funded study say microbial communities are crucial for soil to function as it should do.
Dr Robert Griffiths, a molecular microbial ecologist at the Centre for Ecology & Hydrology (CEH), who is one of the paper’s co-authors, explained: “These organisms are highly diverse and are responsible not only for producing the soil we need to grow crops, but they also provide humans with many other benefits, such as cleaning water and regulating greenhouse gas emissions.
“Unfortunately we cannot grow most of these in the lab so we know very little about the main players and have to rely on genetic methods to identify the microbes.”
CEH scientists are testing thousands of soil samples to understand which microbes are found in different soils. This involves DNA sequencing to read the genetic code of microbes directly from soil DNA and therefore identify the organisms.
Professor Mark Bailey, Director of CEH, was also a co-author on the paper, said: “These genetic methods have revealed a lot about the types of microbes found in different soils, but we don’t yet know how these organisms will respond to climate change events such as drought. This study identifies key soil organisms which are affected by drought.
“We now need to understand more about their genetic machinery in order to better predict how different land managements across different soils will affect the way soils work to deliver human benefits in the future.”
These genetic methods have revealed a lot about the types of microbes found in different soils - Professor Mark Bailey
Research for the paper, titled Soil bacterial networks are less stable under drought than fungal networks, involved scientists from the UK, Italy, Sweden and France.
They compared the effects of drought on bacterial and fungal communities in soil, and found that drought increased the abundance of a certain fast-growing, drought-tolerant grass. With greater above-ground vegetation comes an increased rate of evapotranspiration – the cycle of transfer of water from plants to the atmosphere - thereby lowering the overall soil moisture.
Bacteria, but not fungi, were directly affected by this newfound abundance of grass. Due to the interactions between plant and microbial systems, this change in plant community composition could cause long-term consequences on bacterial communities.
Unlike past research, this study considered the multitude of direct and indirect interactions occurring between different microbial organisms in soil. Rather than focusing on select attributes of bacteria and fungi, this research takes a comprehensive approach to studying soil ecosystems.
Soil bacterial networks are less stable under drought than fungal networks. Nature Communications. August 2018. Franciska T de Vries, Rob I. Griffiths, Mark Bailey, Hayley Craig, Mariangela Girlanda, Hyun Soon Gweon, Sara Hallin, Aurore Kaisermann, Aidan M Keith, Marina Kretzschmar, Philippe Lemanceau, Erica Lumini, Kelly E. Mason, Anna Oliver, Nick Ostle,, James Prosser, Cecile Thion, Bruce Thomson and Richard D Bardgett