YouTube: https://youtube.com/watch?v=YJ8PxeSNAIQ
Previous: Eugene Goostman & The Science of What Disgusts You
Next: Why Do Joints Pop And Crack?

Categories

Statistics

View count:590,433
Likes:13,541
Dislikes:151
Comments:1,056
Duration:04:46
Uploaded:2014-06-23
Last sync:2019-06-12 17:50
A tree falls in the forest, and we know that, with time, microbes, fungi, insects, and other organisms will kick start the decomposition process, recycling all that organic matter. Come back in a year or two and that tree will look very different.

Now imagine hundreds of dead trees that look almost exactly the way they did nearly three decades ago; no decay, no decomposition. A little spooky, right?

Welcome to the Chernobyl Exclusion Zone.

[Intro theme plays]

It's been twenty-eight years since Reactor #4 at the Chernobyl Nuclear Power Plant exploded and caught fire, following a test gone horribly wrong. It was an accident that ultimately released hundreds of times more radiation than Hiroshima, and remains the worst nuclear disaster in history.

Nearly three decades later, a 2,600-square-kilometer around the accident remains cordoned off to nearly everyone. The Chernobyl Exclusion Zone extends about thirty kilometers in every direction from the Ukrainian city of Pripyat, covering portions of southern Belarus as well. An area once home to nearly 200,000 people is now essentially devoid of any permanent residents.

Instead, the Exclusion Zone has become a one-of-a-kind living lab to study the long-term effects of enormous amounts of radiation on wildlife.

But no one, including scientists studying these effects, can visit for long. While radiation levels vary considerably, humans who visit the Exclusion Zone can be exposed to as much radiation in ten days as they would be in a year in the U.S.

Let's start with those trees. Today, it's known as the Red Forest, but in 1986 it was the Wormwood Forest; four thousand acres of scotch pine exposed to some of the highest levels of radiation in the days following the accident. The trees absorbed radioactive isotopes of strontium, cesium, plutonium, and uranium, released by the fire. Most of the pines turned reddish-brown and died within a week.

And recent studies have found that the contamination also had a devastating effect on many of the small organisms so vital to causing decay and maintaining balance in the ecosystem, mainly those fungi and microbes I mentioned.

Meaning, the dead trees look almost exactly the same as they did a quarter-century ago. The ionizing radiation that so efficiently killed the trees and fungi had a similar effect on some animals. Radiation damages living tissue in a variety of ways including breaking down strands of DNA.

This likely explains the collapses that have been observed in populations of bees, spiders, and dragonflies, with mutations ranging from albinism to sperm irregularities.

Some bird populations, meanwhile, have been found to suffer from disruptions of the nervous system, and reduced brain size, likely the result of low levels of antioxidants, which typically help to protect cells from environmental stress.

While many of the isotopes with the short half-lives have already disappeared thanks to their radioactive decay, others continue to threats today.

Cesium-137 is one of the most dangerous isotopes to humans and has a half-life of thirty years, meaning levels are still elevated in the region, even as far away as Norway.

But, it's not all doom and gloom within the Exclusion Zone, although scientists are perplexed about the varying degrees of radiation sensitivity they've found around Chernobyl.

While the initial fallout decimated the scotch pines, for example, nearby birch and aspen trees prove to be much more resistant and continued to grow and spread, and while the wheat seeds from Chernobyl have proved to be still genetically unstable, soybean plants appear to have adapted, increasing their levels of a protein known to protect against ionizing radiation.

Similarly, a recent study in the journal Functional Ecology found that some bird species are now producing higher levels of antioxidants, resulting in less genetic damage.

But perhaps most perplexing of all, large mammals appear to be flourishing, as the Exclusion Zone has paradoxically become an unintentional nature reserve. Populations of boars, bears, elk, deer, wolves, and moose have all been spotted - even the lynx, an animal rarely seen in this region before the accident, has returned in relatively large numbers.

This does not necessarily mean that these animals are healthy, though. Cesium-137 accumulates as it passes up the food chain, and these mammals at the top at the top of the chain are assumed to be accumulating the radioactive isotope in their muscle tissues, as well as strontium in their bones.

But so far, there's been no definitive study of these populations so no one knows for sure how these mammals are surviving in the zone, or what their long-term prospects might be.

Me? I'm just happy to observe, all the way from over here, keepin' my distance.

Thanks for watching this SciShow Dose, and if you'd like to keep exploring the world with us, go to https://subbable.com/scishow to find out how you can become a supporter, and don't forget to go to https://www.youtube.com/user/scishow and subscribe.

[End Theme plays]