Not That There’s Anything Wrong With That?
The compelling icon for an Arctic melting due to climate change is the cuddly, adorable polar bear -- which is losing its habitat. Will the icon for an Everglades polluted by mercury emissions from coal-burning power plants become the graceful white ibis -- which is turning gay because of hormonal changes caused by the toxic heavy metal?
University of Florida researchers studying why mercury pollution seems to reduce breeeding of the long-legged water birds were surprised to find that the more mercury a male ibis ate, the more likely it was to pair up with amother male. "We knew mercury could depress their testosterone levels,” says Peter Frederick, the University of Florida wildlife ecologist who led the study. “But we didn't expect this."
The fear is that if large numbers of ibises or any other species suffer similar effects from mercury ingestion, the species’ breeding rates could plummet. Mercury finds its way into waterways and wildlife diets after being released by power plants, mines, and medical- and municipal-incinerators. In water, bacteria converts mercury to highly toxic and easily absorbed methylmercury. To gain some insight into its effect, over three years the researchers fed the ibises food pellets that contained mercury levels equivalent to those measured in shrimp and crayfish in their normal wetland habitats.
The paired-up males “pretty much did everything except lay eggs,'' Frederick says. "They built nests, they copulated, they sat in the nests together.''
Even if you're feeling a bit squeamish, there’s no cause to become ibo-phobic. “Honestly, there is zero relevance for humans,” Frederick adds. But the group’s findings are worrisome, the latest in a long line of studies of mercury and other endocrine disrupters that affect reproductivity in creatures large and small.