Featured Research

from universities, journals, and other organizations

New Study Sheds Light On Frog Malformations

Date:
June 19, 2002
Source:
American Chemical Society
Summary:
The emergence of mutant frogs with extra arms and legs may smack of a low-budget sci-fi script. But it is a reality, and a new study provides more evidence that ultraviolet radiation could be responsible. The findings are reported in three consecutive papers in the July 1 print issue of Environmental Science & Technology, a peer-reviewed journal of the American Chemical Society, the world's largest scientific society.

The emergence of mutant frogs with extra arms and legs may smack of a low-budget sci-fi script. But it is a reality, and a new study provides more evidence that ultraviolet radiation could be responsible. The findings are reported in three consecutive papers in the July 1 print issue of Environmental Science & Technology, a peer-reviewed journal of the American Chemical Society, the world's largest scientific society. Concern has been mounting for years over the depletion of the ozone layer — the atmospheric shield that helps block harmful ultraviolet (UV) radiation from reaching the Earth's surface. At the same time amphibian populations have been declining, and many have been turning up with unusual malformations, such as missing or extra limbs.

Related Articles


A number of causes have been suggested to explain the malformations, including exposure to chemicals and parasites. Only recently have researchers been examining the potential connection to UV radiation to determine if it is coincidence or something more.

Until now, most of the research has focused on exposing frogs to UV radiation in the laboratory, providing little information about how these findings translate to natural habitats. "We really wanted to fill the gap between the findings of other laboratory research and what might happen in natural environments," said Steve Diamond, Ph.D., an environmental toxicologist at the United States Environmental Protection Agency in Duluth, Minn., and an author on all three papers.

In the first study, Diamond and his colleagues kept frog eggs in small outdoor containers while exposing them to varying degrees of UV radiation — from 25 to 100 percent of natural sunlight. As the eggs developed, the researchers observed hatching success, tadpole survival and the presence of malformations. They found that the frequency of malformations increased with increasing UV radiation, with half of the frogs experiencing malformations at 63.5 percent of the intensity of natural sunlight.

This supplements data from a previously published paper, which reported that 100 percent sunlight reduces survival by an average of 50 percent. In the course of these experiments, the researchers also determined that a specific region of the UV spectrum, known as UVB, appears to cause the malformations.

In the real world, however, frogs rarely experience 100 percent of natural sunlight. A variety of environmental factors conspire to reduce the levels of UV radiation entering wetlands, including ozone levels, cloud cover and UVB-absorbing dissolved organic carbon (DOC) in water. Accordingly, in the second study, the researchers measured DOC levels in wetlands in Wisconsin and Minnesota and found that the top five to 20 centimeters of wetlands absorb as much as 99 percent of UVB.

To complete the picture, the third study involved a survey of 26 wetlands in the same region to estimate the specific level of risk of frogs living in these environments. Using a combination of computer models, historical weather records and DOC measurements, they concluded that UVB posed a risk to amphibians living in three of the 26 wetlands.

While these findings suggest that most frogs are not currently at risk for UVB effects in this area of the country, the possibility of effects on amphibians in general should not be completely ignored, according to Diamond. Continued reduction of ozone and other global climate change effects may increase UV exposure in wetlands, suggesting that the potential risk to amphibians should continue to be studied.

Diamond's team and a group of researchers from the National Parks are presently evaluating UVB levels across landscapes to compare them with the occurrence or absence of amphibians. "Those results," Diamond said, "combined with the risk assessment presented in these three manuscripts, will add significantly to our understanding of the relationship between UVB levels and amphibian declines or malformations."


Story Source:

The above story is based on materials provided by American Chemical Society. Note: Materials may be edited for content and length.


Cite This Page:

American Chemical Society. "New Study Sheds Light On Frog Malformations." ScienceDaily. ScienceDaily, 19 June 2002. <www.sciencedaily.com/releases/2002/06/020619074058.htm>.
American Chemical Society. (2002, June 19). New Study Sheds Light On Frog Malformations. ScienceDaily. Retrieved February 27, 2015 from www.sciencedaily.com/releases/2002/06/020619074058.htm
American Chemical Society. "New Study Sheds Light On Frog Malformations." ScienceDaily. www.sciencedaily.com/releases/2002/06/020619074058.htm (accessed February 27, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Friday, February 27, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Amazon Keeps Its Green Thanks To The Sahara Desert

The Amazon Keeps Its Green Thanks To The Sahara Desert

Newsy (Feb. 25, 2015) Satellite data shows the Amazon rainforest supports its lush flora with a little help from Sahara Desert dust. Video provided by Newsy
Powered by NewsLook.com
Mayor Says District of Columbia to Go Ahead With Pot Legalization

Mayor Says District of Columbia to Go Ahead With Pot Legalization

Reuters - News Video Online (Feb. 25, 2015) Washington&apos;s mayor says the District of Columbia will move forward with marijuana legalization, despite pushback from Congress. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Marijuana Nowhere Near As Deadly As Alcohol: Study

Marijuana Nowhere Near As Deadly As Alcohol: Study

Newsy (Feb. 25, 2015) A new study says marijuana is about 114 times less deadly than alcohol. Video provided by Newsy
Powered by NewsLook.com
Fox With Horrifying Injury Rescued and Released Back Into the Wild

Fox With Horrifying Injury Rescued and Released Back Into the Wild

RightThisMinute (Feb. 25, 2015) This wounded fox knew what she was doing when she wandered into the yard of a nature photographer. The photographer got "Scamp" immediately in the hands of Wildlife Aid and she was released back into the wild in no time. Video provided by RightThisMinute
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins