Maya civilization from the 2nd to 9th centuries So, Tikal, Karakurum City-states such as these have developed, and each has a monarch and is fighting for hegemony. Around the 5th century, Uxmal in the northwestern part of the Maya Lowlands , Northeast Cover , Palenque, Yaschilan, Calakmul, Tikal, Pecan, Copan from the west in the southern part of the Maya Lowlands Large cities such as these have developed, and many other small and medium-sized city-states have been formed.
This time, I would like to explain why the city-state Tikal, which has prospered for more than 700 years, has perished.
City-state Tikal of the ancient Mayan civilization
Tikal Is the largest temple in the Maya that flourished in the rainforest, and is said to have a population of 60,000 to 100,000 at its peak. Caribbean Sea and Usumacinta River Jade and Quetzal feathers, obsidian Etc. were being traded.
It seems that the settlement was formed in this Tikal around 800 BC, and by the 1st century, the prototype of the city was completed and the pyramid was also made. In the 9th century, the cities of Central Maya declined, and Tikal was no exception. The last stone monument of Tikal says 869, and it is believed that Tikal slowly and surely perished over 50 to 100 years.
The cause of the decline is unknown, but land exhaustion, climate change, and plague due to population growth. Although various thoughts have been made, new research has discovered pollution of water sources.
Tikal's water storage mechanism for water shortage
Although it has a population of 60,000 to 100,000 at its peak, there are no water sources such as rivers and lakes . It doesn't rain in the dry season, and the fertile land is well-drained with volcanic ash , Difficult to secure drinking water and agricultural water was doing.
As a measure against chronic water shortages, the ground of the entire city was plastered to prevent water from seeping into the ground . Is called. The ground has a calculated invisible slope, and how the flowing water flows into each reservoir The whole city is a water storage device It played a role like.
Furthermore, the reservoir is also divided into three stages according to the height difference, and the top is clean water and the lower it is, the more dirty the water becomes, and even a mechanism to effectively reuse less water has been established.
Tikal Reservoir Survey
In this study, as a result of investigating the reservoirs in the city, it was discovered that the water source was contaminated with toxic substances so that drinking water could not be drunk.
The area around Tikal was a fertile land that was prone to severe drought and was cut off from water sources by lakes and rivers. Securing water sources is important in these cities, and Tikal stored rainwater in reservoirs and used it as drinking water for people.
So researchers focused on this reservoir and investigated whether the Tikal water supply system was really suitable for maintaining the population. As a result of the investigation, I found something unexpected.
Outbreak of blue powder
As a result of the investigation, cyanobacteria =cyanobacteria from four reservoirs I found the DNA of.
Cyanobacteria are the cause of the blue-green algae phenomenon, and as shown in the above picture, blue-green algae are a phenomenon in which the water surface is covered with algae as if they were sprinkled with blue powder. It can also be seen in modern Japanese lakes and marshes, and is considered to be a typical example of water pollution.
It also produces tap water mold odors that produce toxic chemicals from reservoirs. Planct Slix And generate neurotoxins Microcystis Two kinds of algae were found. The problem with these algae is that they are strong against boiling and even if they are boiled and used, people who drink them will get sick . The researchers said it would be.
However, the occurrence of algae means that the reservoir was in the state shown in the above picture, so perhaps no one would have thought of drinking the water in the reservoir.
Very toxic mercury mixed in
Further investigation reveals two reservoirs near palaces and temples Has a high level of mercury It turned out that was included. To this, researchers may have infiltrated from the underground bedrock and the ash fall that forms the fertile land . However, we came up with another possibility because mercury contamination was not confirmed in the reservoir where ash was thought to have fallen.
It is possible that the Maya brought mercury into the water source.
In ancient Mayans, red pigments are used for murals, pottery patterns and ornaments of buildings. Was using. The red pigment can be combined with iron oxide to obtain various shades, and there is mercury sulfide . It is said that it used the minerals of.
The danger of mercury sulfide may have been known to the Maya, but even with care, it is possible that paint such as murals may have flowed out into the reservoir over time. As a result, it contaminated the reservoirs near temples and palaces where paint was heavily used.
It is possible that the use of water from the reservoir near the temple, which the rulers would have used a lot, reduced the city's leadership.
Large-scale drought and water pollution in the latter half of the 9th century
Large-scale drought in the latter half of the 9th century due to worsening water pollution at water sources Attacks and it is difficult to secure cool drinking water Tikal will be hit hard. The devout Maya people may have thought that the Maya gods were angry at these droughts.
One cannot live without water. If that water isn't available, it's a good reason to abandon the place. In this way, it is believed that the ancient city of Tikal was destroyed over 50 to 100 years.