They discovered the secret of the Great Wall of China's resistance to erosion: biocrusts

The The Great Wall of ChinaWinding for hundreds of kilometers through the mountains and plains of that Asian country, A Iconic historical site And incomparable.

Construction of a wider network the walls, Strength and many others Forts started in 7th century BC. continued until 17th century AD The monumental structure has stood the test of time, thanks in part to “Living Skin.”

A small international team of experts Protection of soil and water ecosystems has discovered that Adherent Bioreactors Parts of the structure help protect it itching. The findings are presented in an article recently published in the journal Scientific advancesThere the study and analysis of the material growing on the wall was described.

The The Great Wall of China It was built over several centuries, starting in approx 221 BC; It had its function To protect people Those who lived behind it from enemies who tried to invade them, those who were on the other side. Previous research has shown that different parts of the wall are mainly made of different materials Crashed Earth or stone.

These soils are formed by mixing organic matter with other minerals. By their very nature, these compounds are abundant Prone to itching. This has led to questions about how wall sections made of this material have survived over the years.

Mission, led Soil and Water Conservation Research Centre And Environmental environment of Chinese Academy of Sciences, He sought to understand the reasons and, at the same time, identify possible methods of cooperation in defense. The researchers wondered if biocrusts might have played a role.

For years, scientists have assumed that these Biocrustsusually enacted Cyanobacteria, lichens and algae, accelerates the corrosion process. To find out if that was the case, the research team collected biocrust samples from various points on the wall and took them to the lab for analysis.

The team measured Mechanical resistance and soil stability Samples. He also tested sections of the wall, directly comparing those encased in biocrust and those exposed directly to the elements. This led to the discovery of bioreactors They are stronger than the resulting rammed earth material; In some cases, three times stronger.

Researchers have also found resistance to was due to biocrusts to the secretion of tightly bound polymers. The research team concluded that the biocrusts contained, rather than accelerated, erosion Slowed down the processHelps preserve the iconic structure.

Similar to these findings was a group of University of Granada who works HondurasHe found that organic plant material added to plasters by the early Mayans helped Reduces corrosion The stone structures they built.

In this latest investigation by experts from China, it was verified Biocrust comprises 67% of studied sections. Its existence will improve Reduces mechanical stability and corrosion of Great wall. Areas covered with biomass were visualized in comparison to bare rammed earth Reduced porosity, water holding capacity, erosion and salinity From 2 to 48%, they increased Compressive strength, penetration resistance, shear resistance and stability of aggregates between 37% and 321%.

* Go Xiao A professional at the Research Center on Soil and Water Conservation and Environmental Ecology of the Chinese Academy of Sciences.