The Great Wall of China, one of the world's most iconic landmarks, has a natural defense mechanism against deterioration, a recent study revealed.
Portions of the Great Wall constructed with rammed earth, a technique that compresses natural materials with soils, have been considered weak points in its structure. However, as reported by CNN, researchers have discovered that these sections are now protected by what they call a "living skin" made up of tiny plants and microorganisms known as biocrusts.
The study, published in the journal Science Advances, found that biocrusts play a crucial role in maintaining the stability and strength of the Great Wall. Covering over two-thirds of the rammed earth sections built during the Ming Dynasty, biocrusts consist of cyanobacteria, algae, moss, fungi, and lichen. Contrary to previous beliefs, these biocrusts actually enhance the wall's resistance to erosion and improve its stability.
According to Bo Xiao, a professor of soil science at China Agricultural University and co-author of the study, biocrusts act like a protective blanket, shielding the Great Wall from environmental threats such as wind, water, and salt. These tiny organisms produce substances that bind soil particles together, making the structure stronger and more resistant to weathering.
"They thought this kind of vegetation was destroying the Great Wall. Our results show the contrary," said Xiao. "Biocrusts are very widespread on the Great Wall and their existence is very beneficial to the protection of it."
The positive impact of biocrusts extends beyond the Great Wall. These communities of plants and microorganisms stabilize soil, increase water retention, and regulate nitrogen and carbon fixation. They are estimated to cover 12% of the Earth's surface and are crucial for maintaining the health of dryland ecosystems.
Emmanuel Salifu, an assistant professor at Arizona State University, sees the new study as evidence of the advantages of engineering biocrusts for the preservation of historic sites like the Great Wall, as reported by CNN.
Protecting landmarks in a green and sustainable way is super important. It's not just preserving history; it's also ensuring that these special places continue to be a source of joy and learning for future generations in harmony with the environment.
For example, Banff Wildlife Crossings Project installs wildlife crossings, which keep both the park's animal residents and visitors safe. It reduces car collisions with wildlife by a staggering amount, showing how we can care for our landmarks and the planet at the same time.
The study's authors suggest that their work could pave the way for preserving other rammed earth heritage sites worldwide by cultivating biocrusts. By harnessing the power of these tiny organisms, we can work toward cleaner ways of protecting our sites and environment.
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