Antinuclear

Australian news, and some related international items

Chernobyl area: strange failure of dead trees to decompose properly

Forests Around Chernobyl Aren’t Decaying Properly It wasn’t just people, animals and trees that were affected by radiation exposure at Chernobyl, but also the decomposers: insects, microbes, and fungi  By Rachel Nuwer  smithsonian.com  March 14, 2014 Nearly 30 years have passed since the Chernobyl plant exploded and caused an unprecedented nuclear disaster. The effects of that catastrophe, however, are still felt today. Although no people live in the extensive exclusion zones around the epicenter, animals and plants still show signs of radiation poisoning.

Birds around Chernobyl have significantly smaller brains that those living in non-radiation poisoned areas; trees there grow slower; and fewer spiders and insects—including bees, butterflies and grasshoppers—live there. Additionally, game animals such as wild boar caught outside of the exclusion zone—including some bagged as far away as Germany—continue to show abnormal and dangerous levels of radiation.

Chernobyl-fallen-trees

However, there are even more fundamental issues going on in the environment. According to a new study published in Oecologia, decomposers—organisms such as microbes, fungi and some types of insects that drive the process of decay—have also suffered from the contamination. These creatures are responsible for an essential component of any ecosystem: recycling organic matter back into the soil. Issues with such a basic-level process, the authors of the study think, could have compounding effects for the entire ecosystem.

The team decided to investigate this question in part because of a peculiar field observation. “We have conducted research in Chernobyl since 1991 and have noticed a significant accumulation of litter over time,” the write. Moreover, trees in the infamous Red Forest—an area where all of the pine trees turned a reddish color and then died shortly after the accident—did not seem to be decaying, even 15 to 20 years after the meltdown.

“Apart from a few ants, the dead tree trunks were largely unscathed when we first encountered them,” says Timothy Mousseau, a biologist at the University of South Carolina, Columbia, and lead author of the study. “It was striking, given that in the forests where I live, a fallen tree is mostly sawdust after a decade of lying on the ground.” ………

The results were telling. In the areas with no radiation, 70 to 90 percent of the leaves were gone after a year. But in places where more radiation was present, the leaves retained around 60 percent of their original weight. By comparing the mesh with the panty hose-lined bags, they found that insects play a significant role in getting rid of the leaves, but that the microbes and fungi played a much more important role. Because they had so many bags placed in so many different locations, they were able to statistically control for outside factors such as humidity, temperature and forest and soil type to make sure that there wasn’t anything besides radiation levels impacting the leaves’ decomposition.

“The gist of our results was that the radiation inhibited microbial decomposition of the leaf litter on the top layer of the soil,” Mousseau says. This means that nutrients aren’t being efficiently returned to the soil, he adds, which could be one of the causes behind the slower rates of tree growth surrounding Chernobyl.

Other studies have found that the Chernobyl area is at risk of fire, and 27 years’ worth of leaf litter, Mousseau and his colleagues think, would likely make a good fuel source for such a forest fire. This poses a more worrying problem than just environmental destruction: Fires can potentially redistribute radioactive contaminants to places outside of the exclusion zone, Mousseau says. “There is growing concern that there could be a catastrophic fire in the coming years,” he says.

Unfortunately, there’s no obvious solution for the problem at hand, besides the need to keep a stringent eye on the exclusion zone to try to quickly snuff out potential fires that breaks out. The researchers are also collaborating with teams in Japan, to determine whether or not Fukushima is suffering from a similar microbial dead zone.

April 4, 2015 - Posted by | Uncategorized

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