Permafrost is the layer of land that is permanently (perma) frozen (frost) for two or more consecutive years. It has a geological age of more than 15,000 years and is found under the active soil layer that we tread mainly in Canada, Antarctica, Alaska, Russia, Mongolia and northern Europe. It covers approximately 24% of the surface of the Northern Hemisphere and stores huge amounts of methane and carbon dioxide.
However, this permanently frozen layer of land is being seriously threatened by global warming with a series of consequences that are already being felt.
Evidence suggests that between 5 and 15% of the large pool of soil carbon stored in northern permafrost ecosystems could be emitted as greenhouse gases by the year 2100.
The main objective of this study, published in the journalNature Geoscience,has been to analyze the effect of the increase in temperature on the carbon content of the permafrost soil.
“We used a permafrost heating experiment located in the interior tundra of Alaska, proposed in 2008 by Ted Schuur, professor of theNorthern Arizona University”, Describes César Plaza, researcher at the Institute of Agrarian Sciences of the Higher Council for Scientific Research and the Marie Skłodowska-Curie scholarship program, coordinated by the professor of Ecology at the Rey Juan Carlos University, Fernando T. Maestre.
For five years, researchers have sampled Arctic soil to analyze carbon content and composition, using nuclear magnetic resonance as a technique.
Despite its importance, "there are very few direct measures of the changes that are occurring in the carbon content in permafrost soils, due to the technical difficulties that arise as a consequence of the subsidence and compaction of these soils when thawing", César Plaza highlights. To solve these problems, in this work the mineral content of the soil has been used as a reference to study the changes in carbon content.
The main results of this research reveal important losses of soil carbon, both in the heating treatment and in the control treatment. "This phenomenon may possibly be due to the transport of carbon in the lateral water flows of the soil, but also to microbial respiration and the decomposition of organic matter", says researcher Marie Skłodowska-Curie.
The study, above all, points out the importance of making measurements directly on the ground and of extending these measurements to the entire permafrost region to gain a better understanding of how it is affecting climate change.
This work has been carried out during a stay of César Plaza in theNorthern Artizona University, funded through the Marie Skłodowska-Curie scholarship program for experienced researchers to the VULCAN project, coordinated by URJC professor Fernando T. Maestre.
Plaza, C., Pegoraro, E., Bracho, R., Celis, G., Crummer, KG, Hutchings, JA, Hicks Pries, CE, Mauritz, M., Natali, SM, Salmon, VG, Schädel, C. , Webb, EE, Schuur, EAG Direct observation of permafrost degradation and rapid soil carbon loss in tundra.Nature Geoscience, DOI: 10.1038 / s41561-019-0387-6.