Soil erosion reduces the productivity of ecosystems, it changes nutrient cycles and it thus directly impacts climate and society.
A team of researchers recorded temporal changes of soil erosion by analyzing sediment deposits in more than 600 lakes worldwide. The scientists found that the accumulation of lake sediments increased significantly on a global scale around 4,000 years ago. At the same time, tree cover decreased as shown by pollen records, which is a clear indicator of deforestation. The study suggests that human practices and land use-change have intensified soil erosion long before industrialization.
Soils are the foundation for almost all biological processes on the Earth’s land surface. On millennial time scales, their weathering and erosion is controlled mainly by climatic and tectonic impacts. In the short term and at smaller local scales, anthropogenic activities are the main drivers of soil erosion. It remained unclear, however, if soil erosion caused by humans has an impact on the global scale as well.
To address this question, a team of international scientists led by French geoscientist Jean-Philippe Jenny from Max Planck Institute for Biogeochemistry, Jena, Germany, and CARRTEL Limnology Center, Thonon-les-Bains, France, looked back in time regarding soil erosion. They investigated drill cores of sediments from 632 lakes worldwide, which had been collected by pollen scientists during the last decades. “Lake sediments are considered natural archives of erosion activities. All fluxes and processes removing soil, rock and dissolved materials result in chronological sediment layers that are accumulated and preserved at the bottom of the lakes”, says Dr. Jenny.
Continue reading at Max Planck Institute for Biogeochemistry
Image via United States Fish & Wildlife Service
