Melting ice caps, rising sea levels, expanding deserts… The long list of consequences of global warming just goes on and on, and a rather unexpected phenomenon has just been added to it. As a result of research that has been carried out for over 30 years, scientists have just discovered 16 new giant viruses in the soil.
‘We were not looking for giant viruses. Our goal was to isolate bacteria directly from the environment to understand how microbial communities are changing in response to soil warming,’ explains biologist Jeff Blanchard from the University of Massachusetts Amherst (UMass Amherst), co-author of a publication published in the journal Nature Communications, in a press release.
A pocket of underground heat
To go about conducting this study, which just so happens to be the largest that has ever been carried out on global warming, scientists spent 30 years focusing and doing research on an area of a forest close to their campus. They implemented a system of heating cables and wires, similar to those used to prevent frost from forming on American football fields. They were buried around a dozen centimetres under the surface and kept the soil at a temperature around 5°C higher than that of the ambient temperature.
In this outdoor laboratory that artificially replicated climate change, researchers took multiple samples of soil. When these aforementioned predicted temperature conditions were simulated, scientists used more advanced analytical techniques to discover ‘metagenomics’ which is the name given to the genetic material found in a sample taken directly from a complex natural environment.
And the result? Researchers were able to sequence the DNA of more than 2,000 individual cells. A heterogeneous mass, in which Jeff Blanchard and his colleagues were surprised to discover giant viruses.
‘We recovered 16 distinct giant virus genomes in this study, but we are merely scratching the surface,’ added the American researcher.
‘The metagenomic data generated here from a single sampling site contained far more new giant virus genomes than any other data set I have seen to date,’ says bio-informaticist Frederik Schulz, lead author on the paper.
As well as the sheer size of these viruses, it’s the amount of them that was so unexpected for researchers, as Jeff Blanchard highlights.
‘Finding 16 at once is kind of overwhelming, and none of them are the same. If you think of all the soil in the world, if there are 10,000 species of bacteria in a gram of soil, about a teaspoon, imagine how many new giant viruses are out there.’
‘Soil is immensely diverse, and we are only beginning to scratch the surface of the organisms and viruses that inhabit it,’ concludes Lauren Alteio, co-author of the study. Anunexpected diversity that seems to be speeding up climate change’s timeline.