Frogs Die and the Silence Screams:
When talking about all the ways that science was great to a junior high school relative recently, he protested that pursuing science would mean he'd have to dissect frogs very soon. I don't remember dissecting anything until college myself, but the idea of formaldehyde infused frogs and scalpels is apparently quite off-putting to young people these days. However this isn't a post about education or the many misperceptions of teenagers, but the fate of the frogs that have garnered scientists a bad reputation in some circles.
Scientists and doctors are not (usually) sadistic, as suggested by youthful rumors of ritualistic frog dissections. Rather, the drastic decline in frogs as they die en masse across the globe has absolutely dismayed herpetologists and ecologists, who scurry up scarce funds to research the cause of the frogs' demise. "The subsequent silence left a long-lasting impression on me", Australian scientist Jamie Voyles told the journal Science recently, speaking of her experience watching frogs die in a Panama rainforest in 2004.
In 1999 researchers at the University of Maine identified a fungus responsible for 90 of the 120 frog extinctions since 1980. In this week's Science, Voyles and her colleagues describe how this fungus, Batrachochytrium dendrobatidis, kills frogs. The resulting disease first upsets the electrolyte balance across the skin of the amphibians. The skin regulates respiration and osmotic balance inside the frog, and as the disease progresses it disrupts sodium and chloride ions and causes a drop in blood electrolytes causing systemic physiological failure and heart attacks for the frogs.
The optimistic news, if any could be so framed, is that other scientists recently discovered a bacteria species that releases the chemical violacein, which stops the lethal fungal infection. This bacteria is symbiotic to some frog species which manage to repel the fungal infections. This finding suggests that perhaps sometime the devastating fungus could be controlled by managing the bacterial ecology of amphibian skins.
