What Killed These Bald Eagles? After 25 Years, We Finally Know.

[douglas9]

It was 1996, Bill Clinton was president, and endangered bald eagles were dying in his home state of Arkansas.

Twenty-nine were found dead at a man-made reservoir called DeGray Lake, before deaths spread to two other lakes. But what really puzzled scientists was how the eagles acted before they died. The stately birds were suddenly flying straight into cliff faces. They hit trees. Their wings drooped. Even on solid ground, they stumbled around as if drunk.

“We weren’t in the political limelight that often,” says Carol Meteyer, who was then a pathologist for the National Wildlife Health Center, a usually obscure federal agency that investigates animal deaths. But as the toll rose, to more than 70 eagles in total, the mass die-off of America’s national bird in the president’s home state took on outsize symbolic importance. Scientists around the country were detailed to the case, but they kept coming up empty: It wasn’t botulism. It wasn’t heavy metals. It wasn’t pesticides. It didn’t seem to be anything known to man. “About the only thing that hasn’t been tested for is second-hand cigarette smoke,” an official told The New York Times in 1998. “We’ve even had people calling in suggesting that it’s radiation from outer space.”

https://www.theatlantic.com/science/archive/2021/03/humans-accidentally-created-death-trap-bald-eagles/618413/

[secondwind]

1. That was a long but fascinating read.

[BComplex]

3. Sure was. And what a waste! So sad that all those birds had to die like that.

I wonder if that's what's wrong with republican's brains?

[lastlib]

2. spoiler:

The birds died because of a specific algae that lives on a specific invasive water plant and makes a novel toxin, but only in the presence of specific pollutants. Everything had to go right—or wrong, really—for the mass deaths to happen. This complex chain of events reflects just how much humans have altered the natural landscape and in how many ways; unraveling it took one scientist the better part of her career. “It’s just an amazing story,” says Gregory Boyer, a biochemist at the SUNY College of Environmental Science and Forestry...

(snip)

Susan Wilde, an aquatic scientist at the University of Georgia and a lead author on the new study, began looking into the mysterious deaths in 2001. By then, the cause of death had a name, at least—avian vacuolar myelinopathy, or AVM....Scientists had ultimately identified AVM in birds at 10 lakes in six southeastern states—all man-made and all being taken over by an invasive plant called Hydrilla verticillata. Wilde had written her doctoral dissertation about one of the lakes before it was invaded by hydrilla; she returned to find dense mats of the hardy plants. They could thrive in the man-made lake, whose waters were too nutrient-poor for native species. She saw spots on their leaves too, which she investigated under a fluorescent microscope....She recognized the spots as a new species of cyanobacteria, or blue-green algae, and she immediately thought they had to be important....(Biochemist Timo) Niedermeyer went back to samples collected in the lakes--which revealed a novel molecule found only in the cyanobacteria growing on the hydrilla. The lab-grown cyanobacteria did not have it, nor did hydrilla by itself.

What’s more, this molecule had a formula never seen before, and, unusually, it contained five atoms of the element bromine.

[central scrutinizer]

4. Thanks for posting this

I sent the article to my daughter, who is an environmental engineering grad student at Portland State University.

She is writing her thesis on blue green algae blooms and they’ve written a computer model based on DeGray Lake. Those blooms are becoming a regular summer occurrence here in Oregon and whole lakes and adjoining campgrounds have to be closed for public safety. Dogs that love water are especially vulnerable.

[eppur_se_muova]

5. Line formula and XRD structure, for anyone who's interested ...

I felt compelled to look this up to see if it was derived from brominated biphenyls or biphenyl ethers, which were once widely used as flame inhibitors. Looks like no ... but now I wonder if some of the harmful PBB isomers might be near-isosteres of aetokthonotoxin, and have similar effects.