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Black mushrooms of Chernobyl. Unidentified life created by radiation

Life can tame even deadly radiation and use its energy for the benefit of new creatures.

Contrary to many expectations, the disaster at the Chernobyl nuclear power plant did not turn the surrounding forests into a dead nuclear desert. There is no silver lining, and after the establishment of the exclusion zone, anthropogenic pressure on the local nature sharply decreased. Even in the most damaged areas, plant life quickly recovered; wild boars, bears and wolves returned to the Pripyat valley. Nature comes to life like a fabulous Phoenix, but an invisible suffocating grip of radiation is felt everywhere.

“We walked through the forest, the sky turned into a magnificent sunset,” says Christopher Robinson, an American microbiologist who worked there in 2018. – In a wide meadow, we met horses, about forty. And everyone had yellow eyes, with difficulty distinguishing us, passing by. ” 

In fact, animals massively suffer from cataracts: vision is especially sensitive to radiation, and blindness is the usual result of a long life in the exclusion zone. In local animals, developmental disorders are often found, cancer often occurs. And even more so, it is fatal to stay near the former epicenter of the accident.

Chernobyl

The fourth block, which exploded in 1986, a few months later was sheltered by a protective sarcophagus, which collected other radioactive waste from the site. But already in 1991, when microbiologist Nelly Zhdanova and her colleagues examined these residues with the help of remotely controlled manipulators, life was revealed here. The deadly debris has been populated by thriving communities of black mushrooms. Over the following years, representatives of approximately one hundred species were identified among them. Some of them not only withstand the murderous level of radiation, but are even drawn to it, like plants – to the light.

Survival

High-energy radiation is dangerous for all living things. It easily damages DNA, causing mutations and errors in the code. Heavy particles can break down chemical compounds like cannonballs, leading to the appearance of active radicals that immediately interact with the first neighbor they come across. A sufficiently intense bombardment can cause the radiolysis of water molecules and a shower of random reactions that kill the cell. Despite this, some creatures demonstrate amazing resistance to such an impact.

Unicellular organisms are relatively simple in structure, and it is not so easy to disrupt their metabolism by free radicals, and powerful protein repair tools quickly repair damaged DNA. As a result, fungi can absorb up to 17,000 Grays of radiation energy – many orders of magnitude more safe for humans. Moreover, some of them literally enjoy such a radioactive “rain”.

The famous Evolution Canyon near Mount Carmel in Israel with one slope oriented towards Europe, the other towards Africa. The difference between their illumination reaches 800%, and the “African” slope exposed to the sun is inhabited by fungi that grow better in the presence of radiation. Like those found in Chernobyl, they look black due to the large amounts of melanin. This pigment is able to intercept high-energy particles and dissipate their energy, keeping cells from damage.

Having dissolved such a mushroom cell, under the microscope you can see its “ghost” – the black silhouette of melanin, which accumulates in the cell wall in concentric layers. Mushrooms on the “African” side of the canyon contain three times as much as the inhabitants of the “European” slope. They are rich in many microbes living on the highlands, which in vivo receive up to 500-1000 Gray per year. But even such a decent amount of absorbed radiation for mushrooms is nothing. It is unlikely that all this melanin is produced for protection alone.

Prosperity

Nelly Zhdanova in 1991 demonstrated that the mushrooms taken near the Chernobyl reactor stretch in the direction of the radiation source and grow better in her presence. In 2007, these results were developed by US biologists Arturo Casadevalu and Ekaterina Dadachova. Scientists have shown that under the influence of radiation hundreds of times higher than the natural background, black melanized mushrooms (Cladosporium sphaerospermum, Wangiella dermatitidis and Cryptococcus neoformans) absorb carbon from the nutrient medium three times more intensively. At the same time, mutant albino mushrooms, incapable of producing melanin, transferred the radiation easily, but grew at the usual pace.

Mushrooms

It is worth saying that melanin can be present in cells in slightly different chemical configurations. Its main form in humans is eumelanin, it protects the skin from ultraviolet radiation and gives it a brown-black color. The red color of the lips and nipples is determined by the presence of pheomelanin. And it is pheomelanin that produces fungal cells under the influence of radiation, although in such quantities it looks completely black.

The transition from eu to pheomelanin is accompanied by increased electron transfer from NADP to ferricyanide – this is one of the first steps in glucose biosynthesis. It is not surprising that, according to some assumptions, such fungi are capable of carrying out reactions similar to photosynthesis, but instead of light they use the energy of radioactive radiation. This ability allows them to survive and thrive where more complex and fastidious organisms die.

Large amounts of highly melanized fungal spores are found in sediments of the early Cretaceous period. In that era, many animals and plants died out: “This period coincides with the transition through the“ magnetic zero ”and the temporary loss of the“ geomagnetic shield ”that protects the Earth from radiation,” writes Ekaterina Dadachova. Such a situation could not take advantage of the mushrooms, radiotrophs. Sooner or later, we will take advantage of this.

Application

The use of melanin to utilize radiation energy is just a hypothesis. However, research continues, the benefit of the radiotrophs can not be called something exotic. In conditions of a lack of resources and sufficient radiation, some common mushrooms can enhance the synthesis of melanin and show the ability to “eat radiation.” For example, the above C. sphaerospermum and W. dermatitidis are widespread soil organisms, while C. neoformans sometimes infect humans, causing infectious cryptococcosis.

Source: Popmech

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Planet Earth

Geneticists have clarified the origin of American slaves

Frame from the movie "Django Unchained" - imdb.com

It is the largest study of DNA from people living in the Americas. It shows where the slaves came from in the United States and reveals the details of their abuse.

The work includes information on 50 thousand people, of which 30 thousand are of African origin. The article, published in the American Journal of Human Genetics , serves as “evidence that genetics can shed light on history,” said Alondra Nelson, professor of social sciences at the Institute for Advanced Study in Princeton.

The study began with the work of Joanna Mountain, senior director of research at the company 23andMe. Together with the team, she created a genetic database, which included mainly information about the company’s clients, whose grandparents were born in regions where slavery flourished. Dr. Stephen Micheletti, the geneticist at 23andMe who led the study, compared it to data from the Slave Travels digital project, which contains information about the people brought in: information on ports of embarkation and disembarkation, the number of enslaved men, women and children. He also collaborated with historians to learn more about the plight of African regions, such as contemporary Angola and the Democratic Republic of the Congo, in the 17th and 19th centuries.

Scientists have found out: the DNA of the study participants from the United States showed their Nigerian origin. This means that there are far more ships that transported enslaved people directly to America from Nigeria than would be expected based on historical records. 

At first, historians “could not believe how many Nigerian ancestors were there in the United States,” Micheletti said. 

Later, after consulting with experts, the study authors learned that slaves were first sent to the British Caribbean Islands, and only then sold to the Americans.

Percentage of people of African descent in Africa, the Americas, and Europe. Red denotes the descendants of slaves from Senegal and Gambia, blue - from the west coast of Africa, green - from Nigeria, orange - from Congo / © Stephen Micheletti
Percentage of people of African descent in Africa, the Americas, and Europe. Red denotes the descendants of slaves from Senegal and Gambia, blue – from the west coast of Africa, green – from Nigeria, orange – from Congo / © Stephen Micheletti

Experts estimate that more than half of the people were brought into the United States and Latin America from West Africa. The study found that the modern black population is genetically related to six regions, among them Senegal, Gambia, Nigeria and Benin. Moreover, according to historical sources, there were more regions from which slaves were exported.

The work also showed that the brought women made a much greater contribution to the modern gene pool than men, although there were much fewer of them. Scientists have calculated that in the United States there are 1.5 times more descendants of slaves, and in Latin America and the Caribbean – 13-17 times. Moreover, in the United States, European men have influenced the modern gene pool of people of African descent three times more than European women, and 25 times more in the Caribbean.

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Planet Earth

The collapse of humanity is predicted with a 90% probability

A new study by theoretical physicists cites truly horrifying numbers. The results of a great deal of work have shown that if human society continues to move in the same direction, then civilization in the form in which we know it now will come to an “irreversible collapse” in a few decades.

The research findings, published in Scientific Reports, are a model for our future. The work is based on data on current rates of deforestation and other resource use. Scientists say that even the most positive forecasts show a 90% chance of disaster.

Physicists at the Alan Turing Institute and Tarapaki University predict that the last forests on Earth will be cleared somewhere between 100 and 200 years of this century.

Combined with global population changes and resource consumption, this is an incredible blow to humanity. In light of this, scientists say that society as we know it may cease to exist within the next 20 to 40 years. There is good news, the researchers note that from a global perspective, the rate of deforestation has actually slowed in recent years.

However, they are still too large and continue to suffer losses as newly planted trees cannot protect the environment as well as mature forests.

“Calculations show that while maintaining the real rates of population growth and consumption of resources, in particular forest resources, we have several decades left before the irreversible collapse of our civilization,” the article says.

A fundamental transformation will be required to prevent collapse. The authors say that the main driving force behind the collapse right now is that the consumption of planetary resources is not taken seriously because it is driven by the economy.

Our civilization gives preference to the interests of individuals, countries or territories, without caring about the entire ecosystem. Therefore, in order to stop the catastrophe, people need to reconsider the current model of society, and accept the one that puts the interests of the ecosystem above the individual.

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Planet Earth

Overpopulation is canceled. Scientists predict a drop in the number of people on Earth

In the next fifty years, the world’s population will decrease, according to American scientists. Moreover, by the end of the century, more than half of humanity will be very old. These data contradict previous forecasts. 

Overpopulation is near

In the middle of the twentieth century, there were about three billion people on Earth. In 1987 – already five, 1999 – six, in 2011 – seven. Based on these data, the United Nations Population Fund (UNFPA) predicted that by 2100 the world’s population will exceed ten billion, and possibly approach 15 billion if the birth rate increases. 

So far, this indicator has only been declining: in the 1950s, there were six children per woman, in 2011 – about two. When forecasting growth, experts based on the fact that humanity as a whole lives better and longer. Australian scientists, after analyzing the statistics of the WHO and the UN, confirmed this scenario. 

They noted that the number of people would grow steadily even if most countries introduced a one-family-one-child policy.Even a global military conflict will not prevent the growth, in which as many people will die as in the First and Second World Wars combined. By 2100, the population will still increase to ten billion, the authors of the work emphasized.

People at the busy intersection of Shibuya district in Tokyo
People at the busy intersection of Shibuya district in Tokyo

According to American researchers, humanity will step over the ten-billion-dollar milestone even earlier – in 2053. True, a rapid leap will happen at the expense of the third world countries, but in developed countries, the population, on the contrary, will significantly decrease. So, Japan will lose 24.7 million citizens, Europe – 12, Russia – 7.9. The population of Africa will double to 2.5 billion.According to researchers from the University of Adelaide, because of this in the near future, people will face a global shortage of water and food. Overpopulation also threatens severe climate change.

Downtrend

The first more cautious forecasts appeared in 2014. An international team of scientists, based on UN data collected before 2012, came to the conclusion that the world’s population by 2100 is unlikely to exceed 12 billion. Most likely, more than 9.9 billion will not work. The main growth will come from the African continent. True, even there there will be more and more elderly people, and fewer and fewer young and able-bodied ones.Now researchers are talking about a possible decline in the population in the next century.

 According to the recent work of American specialists, the indicators will continue to grow only until 2064, then, due to the massive availability of higher education and contraception, a decline will begin. At the time of peak, the planet will have 9.7 billion people, but by 2100 – already 8.8, that is, only a billion more than today. At the same time, the share of people over 80 years old will increase almost sixfold.

Mom with a child in the Japanese city of Sendai
Mom with a child in the Japanese city of Sendai

Such conclusions are the result of examining data not on fertility, but on the cohort fertility of women. That is, about the average number of children born to mothers who have not reached a certain age, in this case fifty years.In total, the work used information about the inhabitants of 195 countries. 

Based on this, scientists have calculated: by the end of this century, fewer children will be born in 183 states than are necessary for reproduction.The maximum losses will be incurred by Japan, Italy, Spain, Thailand and South Korea – the population there will decrease by half. In Russia – up to 106 million. Even China will be in trouble : by 2100, only 732 million people will remain in the country. Fertility will also fall in Africa. In Niger today, there are seven children per woman, which will drop to 1.8 by the end of the century.

Record holders for population decline according to PRB forecasts
Record holders for population decline according to PRB forecasts

Attract young and educated

If the restrained forecast comes true, then the problems with the lack of drinking water and food, which are inevitable when the planet is overpopulated, will disappear by themselves. At the same time, a high proportion of the elderly population is likely to require a restructuring of the current political and economic systems. 

They will not be able to effectively solve the problems facing a rapidly aging society, the authors of the work warn. Experts call an open migration policy of developed countries one of the possible solutions. 

According to the staff of the International Institute for Applied Systems Analysis, the model adopted in Canada and Sweden , attracting a large number of well-educated and able-bodied migrants, can most effectively deal with such a challenge. This option, for example, will solve the problem of the aging of the European population.

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