I read an article in Science News about a toxin that is responsible for "mysterious deaths of bald eagles, mallards and other lake life in the south-eastern United States."
https://www.sciencenews.org/article/bald-eagle-mysterious-die-offs-chemical-toxin-foundBy Susan Milius
March 26, 2021 at 8:00 am
Mysterious deaths of bald eagles, mallards and other lake life in the southeastern United States have puzzled scientists for more than 20 years. After a long slog exploring the quirks of cyanobacteria gluing themselves to an invasive water weed, a research team has found a toxin that could be the culprit.
And it’s an odd one, the team reports March 26 in Science.
Nicknamed AETX, the toxin has an unusual chemical structure requiring building blocks rich in the element bromine, says Susan Wilde, an aquatic ecologist at the University of Georgia in Athens. Yet those bromide building blocks are not routinely abundant in southern lake water. That’s where the life story of a particular water weed comes in.
The mystery of the unknown toxin began at an Arkansas lake during the winter of 1994–95 with the nation’s largest unexplained die-off of bald eagles. The eagles, coots and some other birds lost their motor coordination, struggled to fly or even walk, and had seizures. Checking the ill animals’ brains revealed swathes of unnatural microscopic holes, or vacuoles. By 1998, six states had confirmed bird die-offs with the same disease, now called VM, short for vacuolar myelinopathy...
[end of article:]
The newly discovered exotic chemistry of these toxin-makers doesn’t surprise Jason Stajich of University of California, Riverside, who studies other cyanobacteria in his genetic explorations of microbial evolution. Free-floating cyanobacteria cause toxic blooms in both marine and fresh water (SN: 8/28/18). But this green bacterial group also includes species that create the world we love. The desert crusts Stajich studies (like “bread crust” but on desert surfaces, he says) take years to form and depend on networks of cyanobacteria (SN: 12/10/19).
In this case, now that the suspect has been nabbed, there’s even more reason to get rid of the Hydrilla invaders that facilitate the toxin making. Water birds gorge on the Hydrilla and its ride-along bacteria and thus get a deadly dose of toxin. Predators such as eagles and owls that feast on those water birds also get poisoned. In the lab, the toxin affects other vertebrates, such as amphibians and snakes. Knowing the makeup of the toxin will now let the lab check for effects on mammals. With such a wide range of potentially susceptible creatures, solving the mystery couldn’t have come soon enough.
