After the geese died, researchers found a microorganism living (and thriving) in the extremely toxic lake. This microorganism was filtering out the toxins 900 times more effectively than any other known organism[1]. The origin of the microbe was the gut of the geese. Radiolab included this story in one episode[2].
[1]: https://www.millerwelldrilling.com/miracle-at-the-berkeley-p...