Note: The content of this article refers to the report of the China Wetland Museum on 2016-11-01 in the 40th issue of "National Wetlands" on "Unraveling the Mystery of the Instant Murder in Lake Nios, Cameroon".
In 1986, in the Republic of Cameroon, Africa, a very tragic event occurred.
The villagers of a village, in one night, all suffered a "catastrophe".
More than 1,700 people, and more than 3,000 cattle and sheep, all died overnight.
What's going on here?
"Bizarre" deaths
Lake Nyos is a very beautiful scenery in Cameroon, and the scenery here is breathtaking.
But what many people don't know is that in fact, this lake also has the title of "Murder Lake".
In the seventies and eighties of the last century, the corpses of animals occasionally appeared on the surface of Lake Nyos.
The people who lived near Lake Nyos at that time did not take it seriously, after all, in nature, animal predation and predation are a very common thing.
However, what they didn't expect was that such a thing might just be a "warning".
On the evening of August 21, 1986, after a busy day, people near Lake Nyos lay in bed as usual and prepared to rest.
As the night approaches, many people are already asleep.
But in the wee hours of the morning, there was a loud noise from the side of Lake Nyos, like the sound of an explosion.
A foul smell followed, which soon spread throughout the village.
But after a while, everything was calm again, as if nothing had happened.
The next morning, some people who heard the movement went to Lake Nyos to check, but found a very "strange" situation.
In the village near Lake Nyos, there is no "life" at all, not even the sound of animals, but the corpses of animals that can be found everywhere in the village.
Not only that, but when they entered people's homes to investigate, investigators found that all the people in the village had lost their lives.
After careful examination, it was found that a very small number of people were unconscious, so investigators rushed them to the hospital.
After statistics, it was found that more than 1,700 villagers were killed in this accident, and the cattle and sheep in the village were not spared.
At that time, it was believed that this was the punishment of the gods, after all, the carcasses of animals had already appeared on the surface of the lake.
In fact, there is no real evidence at all for such a statement, and it cannot convince everyone.
And this incident has also attracted the attention of the local government and scholars from all walks of life, and an investigation into this "bizarre death" was immediately launched.
Cause concern, conduct an investigation
In the whole death incident, in fact, every place and every detail is very worthy of in-depth study, such as the time of death of the villagers.
After a forensic examination, it was found that the deaths of the villagers in the entire village were almost all very different, that is, they died at the same time.
This is actually a very strange point, more than 1,700 people, died at the same time?
After that, there was a conjecture of poisoning.
However, this conjecture was quickly disproved, because no lethal toxin was detected in the body of the deceased, which means that it could not have been poisoned together.
In addition to the poisoning, there is a very "bold" speculation, is it possible that this was a massacre?
And such an idea has also been overturned by the facts.
Because in any corner of the village, there were no traces of fighting or blood.
Not only that, but judging from the situation at the scene, the villagers and animals did not even leave any traces of struggle when they died.
In other words, this mass death event is simply not possible for large-scale massacres.
According to the autopsy report, the death of the people was completely like a sudden death of asphyxiation, and there was no warning.
The most puzzling thing is, no matter what the cause of death, why do the animals in the village have a similar situation?
At that time, in order to investigate this matter, the investigation team put forward a lot of bold speculations, but in the end, all of them were overturned.
And based on the memories of those who survived, the investigation team found some clues.
Drain the lake and find out the truth
It is said that on the night of the incident, a huge column of water burst out from the bottom of Lake Nyos, and the sound was like a bomb explosion.
After that, people smelled something similar to rotten eggs, and many people fell into a coma or even died.
After learning this, the investigators set their sights on Lake Nyos and began to understand and investigate some "things" about Lake Nyos.
After going to Lake Nyos to investigate, I didn't find anything unusual on the lake at first, but it was shrouded in a hazy white mist, giving people a feeling of "fairyland".
And this is actually the strangest thing, because the average temperature in Africa is very high, basically around 30 degrees, so it is unlikely that there will be air flowing through the water surface and condensing into fog.
So they took some of the water from the lake and brought it back for research, hoping to find a breakthrough.
When the results of the study came out, all the researchers were shocked because a large amount of carbon dioxide was detected in the water body.
And the white smoke on the water surface is most likely the chemical substance after the chemical reaction of carbon dioxide.
Not only that, but it also deciphers the cause of death: carbon dioxide poisoning.
You must know that the human body has no way to absorb carbon dioxide, when we breathe, we inhale oxygen in the air, and even expel some carbon dioxide.
When the concentration of carbon dioxide around us is too high, then lethargy occurs, and there is no way to get oxygen from the air.
In this way, our brains have no way to work.
Gradually, a situation of brain death will be formed, and with a long period of brain death, our body will gradually enter a state of death.
And this also unravels the reason why people die.
But there is one thing that remains unresolved, and that is why such a high concentration of carbon dioxide occurs in Lake Nyos?
The secret of the bottom of the lake
You know, according to the memories of the survivors, there was a sound similar to an "explosion" in Lake Nyos at that time, and there was also a column of water running into the sky.
Coupled with the carbon dioxide appearing on the surface of the lake, all of this adds up to the word "weird".
In order to solve this puzzle, the experts once again surveyed Lake Nyos, and due to the limited technology at the time, the most direct way was to drain the lake.
In the process, they discovered that Lake Nyos was located in a dormant crater.
It can be said that this is a typical volcanic lake, but it was last erupted 400 years ago, and there was no sign of an eruption until the accident.
But it is precisely because the volcano has not erupted for a long time that those weak magmatic activity has actually released a large amount of gas into the water body, and carbon dioxide is among them.
These gases cannot overflow the water, but can only be blocked under the bottom of the lake, and over time, these gases will become more and more abundant.
According to relevant reports, the magma under Lake Nyos releases 5,000 tons of carbon dioxide every year, and the carbon dioxide in the water accumulates for a long time, so that the water pressure under the water is much higher than the water pressure on the lake.
In fact, just like a soda, we only have the sound of "呑" when we open it normally, but if we shake the bottle a few times before opening it, then the moment it is opened, there will be an eruption of "cola column".
But soda eruptions are conditional, so why is the eruption of carbon dioxide under Lake Nyos?
According to the local weather conditions, a few days before the incident, it rained for several days near Lake Nyos, and there was also a landslide.
You know, under the calm surface of the lake, there is actually a very huge water pressure hidden.
In this case, it only takes a little external force to "add fuel to the fire", then the balance of the entire Lake Nyos will be broken.
And this landslide is the "murderer" who broke the balance.
Because when a landslide happens, everything that slides down in the process goes into Lake Nyos, and it goes down at a very fast speed.
In an instant, the water of the entire lake will erupt upward, forming a huge column of water, and the carbon dioxide that is "ready to move" underwater will directly break out of the encirclement under this "opportunity".
At this moment, the water pressure that has accumulated for many years will directly burst out, and the carbon dioxide that escapes will also be emitted to the surrounding villages, causing all the people to die.
Suffice it to say, that's the truth of the whole thing.
In order to prevent a similar situation from happening again, some experts have proposed a "deflated" method, inserting an exhaust pipe under the water, so that the carbon dioxide inside can be gradually discharged so that it will not be accumulated for many years and then explode.
In fact, this tube is actually the equivalent of us digging a small hole in the bottle of a carbon drink and putting the straw in it.
In this way, no matter how you shake the bottle, when you open it again, in fact, the "water column" that erupts at this time is not as powerful as before.
In the case of Lake Nyos, the carbon dioxide under the lake can also be slowly discharged without exceeding the concentration level all at once, which is also to prevent similar things from happening again.
Not only that, but around Lake Nyos, an alarm has been installed to alert people to safety if the carbon dioxide level in the lake exceeds the standard.
It is also because of this incident that Lake Nyos has become one of the three murderous lakes unique to Africa.
Information sources:
China Youth Network "Can Lakes Kill? Demystifying Cameroon's Mysterious "Murder Lake"2016-02-21
Baidu Encyclopedia "Lake Nyos"