Chinese restorers and biologists have discovered that the growth of algae and bacteria present on the surface of many of the remaining parts of the Great Wall of China protects it from erosion by water, wind, and other factors.
These factors destroyed almost half of the wall over the past 100 years.
The scientists published the results of their study in the journal Science Advances.
The study stated: “We found that cyanobacteria and algae cover about 67% of the parts of the Great Wall that we studied. Subsequent analysis of these sections showed that this layer of microbes and algae increases the mechanical stability of the wall and reduces the rate of its destruction under the influence of various forms of corrosion.”
This conclusion was reached by a team of restorers and biologists led by Xiao Bo, a professor at the China Agricultural University in Beijing, during a case study of a 600-kilometre-long section of the Great Wall of China, which extends to four regions in the People's Republic of China, namely the provinces of Shaanxi and Shaanxi, as well as Mongolia. Interior and Ningxia Hui Autonomous Region.
Scientists collected samples of wall materials from eight different sites in this northern Chinese region and studied their characteristics. To do this, scientists measured the porosity of the soil, which is the compressed soil that forms the walls of the largest military fortification on Earth. They also measured the ability of samples of this material to resist mechanical stress, and monitored the effect of water on these samples.
When the researchers compared these measurements in different areas of the fence, they found that they were unusually affected by whether those areas were covered in different algae and bacteria. If these biomaterials were present in the fortifications, they would have been more stable and better resistant to pressure and various forms of erosion caused by water and wind compared to parts of the walls devoid of algae and microbes.
According to the researchers, the beneficial effect of such growth is due to it reducing the size of the pores and filaments inside the ground crusher, and as a result, water and various particles that accelerate the corrosion process became less able to penetrate it. However, scientists have found that the protective effect disappears at low levels of rainfall, which explains why many fortifications in the more desert areas of China have collapsed, while other parts of the wall have survived to this day.
It is noteworthy that the Great Wall of China, as one of the Seven Wonders of the World, was built in the period between the third century BC and the era of the Ming Dynasty. Its length, with all its branches, is about 21 thousand kilometers. The wall extends from Liaoning Province in northeastern China to Gansu Province in northwestern China. In 1987, this largest architectural monument in human history was included on the UNESCO World Heritage List.
The discovery of a fossil groundwater basin deep in the mountains of Sicily dating back millions of years
A team of geologists has collected evidence of a deep freshwater basin beneath part of Sicily's mountains, 6 million years old.
In their study, published in the journal Communications Earth & Environment, the group used publicly available data, collected from oil discovery efforts, to study groundwater in and around the submountain Gela Formation on the island of Sicily.
As the number of people living on the islands increases, scientists continue to search for resources to support them.
One of these islands is Sicily, which is located off the coast of Italy in the Mediterranean Sea. Officials there are concerned about water supplies for a growing population. So scientists conducted a study of underground freshwater supplies that have not yet been tapped.
The researchers analyzed maps and data from previous surveys looking for oil deposits. They discovered what they believe to be a previously unknown aquifer thousands of feet below the Hybelian Mountains.
They created 3D models of the aquifer to validate their findings and found evidence indicating that it is not only an aquifer, but contains approximately 17.5 cubic kilometers of water.
The team then proceeded to explain how much fresh water could be present under a mountain range. They pointed out that it was trapped there during the Mycenaean salinity crisis millions of years ago, as a period of 700,000 years witnessed a blockage in the Strait of Gibraltar, which allowed many parts of the Mediterranean Sea to dry up, exposing the sea floor to rainwater.
The research team indicates that rainwater seeped into the Earth's crust, and that this rainwater could have accumulated underground, where it was absorbed by carbonate rocks that act like a sponge.
When sea levels returned to normal, fresh water was trapped underground by seawater pressure.
The researchers also found what they believe is a possible ancient rainwater channel, the Malta Escarpment that runs around the eastern parts of Sicily.
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