Climate Change and Frog Disease

Posted by Dawn M. Smith Dec 31, 2007

Amphibians have long been known to camouflage themselves by changing color. But some tree frogs in Costa Rica may also have been using the technique to kill off the chytrid fungus that is devastating amphibians around the world. Comparing these frogs with others who lack this particular pigment may tell scientists whether reduced light levels are involved in the increase in disease.

The scientists are using a new type of scanning mechanism called Optical Coherence Tomography (OCT) to study the changes in the skin of the frogs. Using OCT they don’t have to touch the frogs to get their information, meaning the amphibians are less stressed and the scientists will not unwittingly transmit the chytrid disease by handling the frogs.

The ability to withstand strong sunlight appears to be linked to the presence of a skin pigment known as pterorhodin. The frogs that have pterorhodin also appear to be able to change skin texture to a metallic sheen, which may allow them to withstand higher temperatures, such as those they would be exposed to when basking in the treetops of the rainforest.

Those temperatures may be just what is needed to kill off the chytrid fungus that is affecting frogs populations all over the world. But if, as the scientists suspect, increased cloud cover over the rainforest is reducing the frogs’s exposure to the temperature (or possibly the type of UV light) needed to destroy the fungus, it would help explain why the disease is on the rise.

And give us all one more reason to be concerned about the myriad effects climate change may be having.