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

the Great Wall of Chinawhich extends hundreds of kilometers across the mountains and plains of that Asian country, which is… An iconic historical site And incomparable.

Building a wide network of Walls, strength point And others Fortifications I started to 7th century BC. And it continued until The seventeenth century AD The massive structure has stood the test of time, thanks in part to A “Living skin.”

A small international team of specialists Maintaining soil and water ecosystems It was discovered that Bio-attached crustaceans Parts of the structure protect it from… Stripping. The results were presented in a recent article in the journal Advancement of scienceWhere the study and analysis of the material growing on the wall was described.

the Great Wall of China It was built over several centuries, starting around c 221 BC; It was her job Protect people Living behind it from the enemies they were trying to conquer who were on the other side. Previous research has shown that different parts of the wall were mainly made of different materials He hit the ground Or stone.

This soil is made by mixing organic materials with other inorganic materials. By nature, these compounds are more Prone to corrosion. This has raised questions about how wall partitions made of this material will last for so many years.

Work led Soil and Water Conservation Research Center And Ecological environment Subordinate chinese academy of sciences, He tried to understand the reasons and, at the same time, find possible ways that would help in preserving the environment. We researchers wondered whether crustacean biosynthesis might play a role.

For many years, scientists assumed that this… Biocrustaceansgenerally consisting of Cyanobacteria, lichens and algaeAccelerate the corrosion process. To find out if this was the case, the research team collected samples of the biocrust from various points along the wall and took them to the laboratory for study.

The team measured Mechanical resistance and soil stability of samples. He also tested sections of the wall by directly comparing those covered with bio-veneer and those directly exposed to the elements. Thus it was discovered that biocrusts They were stronger than the rammed earth material on which they grew; In some cases, it is three times stronger.

The researchers also found that resistance It was to be a vital crustacean To secretion The polymers are tightly linked. The research team concluded that instead of accelerating corrosion, the biocrusts did so The process slowed downWhich helps preserve the famous structure.

Something similar to these findings were those of the team from University of Granada Who works in Honduraswho found that organic plant materials added to plaster by the early Maya helped Reduce wear Of the stone structures they built.

In this recent investigation conducted by specialists from China, it was verified that Biocrust covers 67% Of the studied sections. Its presence improves Mechanical stability and reduced wear Subordinate The big wall. Compared with bare rammed earth, biocrust-covered sections showed a Low porosity, water holding capacity, corrosion and salinity Between 2 and 48%, while the percentage increased Compressive strength, penetration resistance, shear resistance The stability of the aggregate is between 37% and 321%.

* Bu Xiao He is a specialist at the Research Center for Soil, Water and Ecological Environment Conservation of the Chinese Academy of Sciences