A ‘living skin’ is protecting the Great Wall of China from erosion

The Great Wall of China used to be much greater. What stands today is only a fraction of the expansive fortifications built on the country’s northern borders starting more than 2000 years ago and then eroded by time. But many sections of the remaining walls seem to be getting preservation help from an unlikely source: thin layers of bacteria, moss, lichen, and other organisms known as biocrusts, which grow on the surface of soils. A study published today in Science Advances finds that these so-called “living skins” have likely protected parts of the Great Wall from wind, rain, and other corrosive forces. And with advances in technology and research, scientists might eventually propagate new biocrusts to spare the wall from further degradation. The work is “innovative and creative,” says Nichole Barger, an ecologist at the Nature Conservancy who was not involved in the new research. She notes it’s not necessarily surprising, however, given the growing recognition of the protective effects of biocrusts: These webs of growth are known to help stabilize dryland ecosystems and prevent soil erosion. Many of the Great Wall’s most well-known and visited sections are made of stone or brick, but other parts were built out of soil compacted by workers, often called rammed earth. Over time, this material can break down as rain seeps in, wind blows the soil away, salt crystals for...
Source: Science of Aging Knowledge Environment - Category: Geriatrics Source Type: research