Chernobyl's birds are adapting to ionising radiation

Apr 28, 2014
Mist nets strung along a pasture near the Chernobyl Nuclear Power Plant. Credit: T.A. Mousseau, 2011

Birds in the exclusion zone around Chernobyl are adapting to – and may even be benefiting from – long-term exposure to radiation, ecologists have found. The study, published in the British Ecological Society's journal Functional Ecology, is the first evidence that wild animals adapt to ionising radiation, and the first to show that birds which produce most pheomelanin, a pigment in feathers, have greatest problems coping with radiation exposure.

According to lead author Dr Ismael Galván of the Spanish National Research Council (CSIC): "Previous studies of wildlife at Chernobyl showed that chronic exposure depleted antioxidants and increased oxidative damage. We found the opposite – that antioxidant levels increased and decreased with increasing background radiation."

The Chernobyl disaster, which occurred on April 26 1986, had catastrophic environmental consequences. However, because it remains heavily contaminated by radiation, the region represents an accidental ecological experiment to study the effects of ionising radiation on wild animals.

Laboratory experiments have shown that humans and other animals can adapt to radiation, and that prolonged exposure to low doses of radiation increases organisms' resistance to larger, subsequent doses. This adaptation, however, has never been seen outside the laboratory in wild populations.

Previous studies of the level of antioxidants and oxidative damage at Chernobyl are limited to humans, two bird species and one species of fish. Because different species vary widely in their susceptibility to radiation, this limited data has made it difficult to study how wild animals adapt to .

Scientists measuring birds inside the Chernobyl Exclusion Zone (Timothy A. Mousseau on left, Anders Paper Møller on right). Credit: G. Milinevski, 2011

The researchers, including ecologists who have worked around Chernobyl since the 1990s, used mist nets to capture 152 birds from 16 different species at eight sites inside and close to the Chernobyl Exclusion Zone. They measured background radiation levels at each site, and took feather and blood samples before releasing the birds.

They then measured levels of glutathione (a key antioxidant), oxidative stress and DNA damage in the blood samples, and levels of melanin pigments in the feathers. Melanins are the most common animal pigments but because the production of pheomelanin (one type of melanin, the other type being eumelanin) uses up antioxidants, animals that produce the most pheomelanins are more susceptible to the effects of ionising radiation.

As well as taking samples from 16 different bird species, the team used a novel approach to analyse their results. The method takes better account of how closely related different species are. This is important because some species are more susceptible to radiation than others. The method focuses the analysis on individual birds instead of species averages, making it a much more sensitive way to analyse biochemical responses to radiation.

The results revealed that with increasing , the birds' body condition and glutathione levels increased and oxidative stress and DNA damage decreased. They also showed that birds which produce larger amounts of pheomelanin and lower amounts of eumelanin pay a cost in terms of poorer body condition, decreased glutathione and increased oxidative stress and DNA damage.

Chernobyl's birds are adapting to ionising radiation
A hawfinch (Coccothraustes coccothraustes) from the Chernobyl exclusion zone. This is one of several species bird species that appears to have adapted to radioactive conditions inside the Chernobyl Exclusion Zone. Credit: T.A. Mousseau and A.P. Møller, 2011

"The findings are important because they tell us more about the different ' ability to adapt to environmental challenges such as Chernobyl and Fukushima," said Galván.

Levels of radiation in the study area ranged from 0.02 to 92.90 micro Sieverts per hour. The 16 surveyed were: red-backed shrike; great tit; barn swallow; wood warbler; blackcap; whitethroat; barred warbler; tree pipit; chaffinch; hawfinch; mistle thrush; song thrush; blackbird; black redstart; robin and thrush nightingale.

Ionising radiation damages cells by producing very reactive compounds known as free radicals. The body protects itself against free radicals using antioxidants, but if the level of antioxidants is too low, radiation produces oxidative stress and genetic damage, which leads to ageing and death.

Explore further: Fresh faced: Looking younger for longer

More information: "Chronic exposure to low-dose radiation at Chernobyl favors adaptation to oxidative stress in birds." Ismael Galván, et al. Functional Ecology, Friday 25 April 2014.. DOI: 10.1111/1365-2435.12283

add to favorites email to friend print save as pdf

Related Stories

Brightly colored birds most affected by Chernobyl radiation

Jul 11, 2007

Brightly coloured birds are among the species most adversely affected by the high levels of radiation around the Chernobyl nuclear plant, ecologists have discovered. The findings – published online in the British Ecological ...

Fresh faced: Looking younger for longer

Jan 10, 2014

Newcastle University researchers have identified an antioxidant Tiron, which offers total protection against some types of sun damage and may ultimately help our skin stay looking younger for longer.

Recommended for you

US charges safari owners with illegal rhino hunts

10 hours ago

Two South African men were charged Thursday by the US government with conspiracy to sell illegal rhinoceros hunts to American hunters, money laundering and secretly trafficking in rhino horns.

Helping sweet cherries survive the long haul

15 hours ago

A new study says that cherry producers need to understand new intricacies of the production-harvest-marketing continuum in order to successfully move sweet cherries from growers to end consumers. For example, the Canadian ...

User comments : 18

Adjust slider to filter visible comments by rank

Display comments: newest first

Egleton
3.7 / 5 (3) Apr 28, 2014
Professor James Lovelock has pointed out that we have evolved on a radio-active planet. The isotopes created in a supernova are not all stable.
philw1776
1.7 / 5 (3) Apr 28, 2014
Birds are adaptable species. These dinosaur cousins were the only dino survivors of the Chicxulub impact. Only the recent invention of house cats threatens the various species.
BobSage
1 / 5 (2) Apr 28, 2014
So I wonder if one should run off the radon remediation system and just bask in the rays.
Modernmystic
5 / 5 (1) Apr 28, 2014
Levels of radiation in the study area ranged from 0.02 to 92.90 micro Sieverts per hour.


Huh? That doesn't sound correct. The average world background radiation is 0.87 mSv/a (milli sieverts/hour). Now a MICRO Sievert is 1/1000th of a milli Sievert. So the radiation they're being exposed to is far below average background as I read it.

Background radiation;

http://en.wikiped...adiation

I'm thinking they meant to say milli instead of micro?
antialias_physorg
5 / 5 (3) Apr 28, 2014
The average world background radiation is 0.87 mSv/a (milli sieverts/hour)

mSv/a means milliSievert per year ("a" stands for "annum")
Modernmystic
5 / 5 (3) Apr 28, 2014
Ahhh that makes sense. Thanks AA.
Modernmystic
5 / 5 (1) Apr 28, 2014
Wait, that doesn't make sense. On the wikipedia page it says that 0.120-0.130 μSv/h is equal to 1.05-1.14 mSv/a. It also says that the world average background is 2 mSv annually;

http://en.wikiped...adiation

So my guess is that it's a misprint under the first picture caption and it should read 0.87 μSv/h?

It can't be both...
TheGhostofOtto1923
3 / 5 (4) Apr 28, 2014
"Chernobyl's birds are adapting to ionising radiation"

-And you can too boys and girls! Radiation is our friend.

Although it might take a number of gens.
kpwalkin
3 / 5 (2) Apr 28, 2014
I wonder if they're using some mechanism to protect the DNA from the radiation and how
Sinister1812
not rated yet May 04, 2014
It's not just birds that are adapting either.
https://www.youtu...ms6vn-p8
katesisco
1 / 5 (1) May 04, 2014
I remember the earlier plant study and the evidence showed that the plants were extracting greater amounts of nutrients from the soil, using it to make more protein which in turn went to protect the plant from radiation. Is not that radiation is good for you.
Let's suppose it happened to us 5 my ago, and we ate chunks of cooked meat which allowed our bodies to make more protein which protected us from local low level radiation. And after millenea, the radiation levels fell off and guess where that extra protein went? Into brain size.
katesisco
not rated yet May 04, 2014
article:

According to lead author Dr Ismael Galván of the Spanish National Research Council (CSIC): "Previous studies of wildlife at Chernobyl showed that chronic radiation exposure depleted antioxidants and increased oxidative damage. We found the opposite – that antioxidant levels increased and oxidative stress decreased with increasing background radiation."

Obviously the protein that went into a luxurious display of feathers was nixed in favor of life extension. Radiation is not good for you.
Jimee
not rated yet May 05, 2014
Gee, maybe people will get healthier if we let them carry around packages of plutonium. Storage problem solved!
Jimee
not rated yet May 05, 2014
Gee, maybe people will get healthier if we let them carry around packages of plutonium. Storage problem solved!
ryggesogn2
not rated yet May 05, 2014
Humans adapted to ionizing radiation with skin and hair color changes.
Captain Stumpy
1 / 5 (1) May 05, 2014

Wait, that doesn't make sense. On the wikipedia page it says that 0.120-0.130 μSv/h is equal to 1.05-1.14 mSv/a. It also says that the world average background is 2 mSv annually;
@Modernmystic
does this link help?
http://wpedia.goo...isievert
Modernmystic
not rated yet May 06, 2014

Wait, that doesn't make sense. On the wikipedia page it says that 0.120-0.130 �ĽSv/h is equal to 1.05-1.14 mSv/a. It also says that the world average background is 2 mSv annually;
@Modernmystic
does this link help?
http://wpedia.goo...isievert


Extremely helpful Capn' thanks!

There seems to be some disagreement amongst various sites on wheter or not microsieverts are larger than millisieverts on conversion tables. However it's my understanding that micro is a millionth and milli is a thousanth. That being the case the radiation they're talking about 0.02 to 92.90 micro Sieverts is actually lower than the Earth's average background radiation.

92*24*365=805,920 microsieverts/year. That's less than 1 sievert per year. The world average is 3.01 sieverts/ year...so something still doesn't sound right.

Modernmystic
not rated yet May 06, 2014
After a little digging I found something else interesting that's related somewhat to this article...

This map shows daily readings of radiation levels in Japan including around Fukushima

http://jciv.iidj.net/map/

The units are in nanosieverts (billionths of a sievert) per hour.

If you zoom right in on Fukushima Dai-ichi you get a reading of about 120,000 nanosieverts, which sounds like a lot. However after the following math:

120,000*24*365=1,051,200,000 nanosieverts/year...which of course is only 1.05 sieverts....

That's less than the world's background right on top of that reactor.