The 'cone of shame' turns into a science lesson
Astrobiologist and professor Dr. Stephanie Olson discovered her dog's fur turned green overnight, and she explained why in a thread. Now the mystery becomes how to remove the stain. Photo via @ExoStephO
by Dr. Stephanie Olson
I was alarmed to discover that my dog turned GREEN overnight. I had no idea why. But it turns out that, as an early Earth geochemist, I was perfectly prepared to find out! The story begins with a lot of drool. Usually it ends up on my floors and walls or the pants of visitors. But while Olive is recovering from surgery, her cone collects and funnels her juices down her neck.
The story begins with a lot of drool. Usually it ends up on my floors and walls or the pants of visitors. But while Olive is recovering from surgery, her cone collects and funnels her juices down her neck. pic.twitter.com/yRRZyzIbdV— Dr. Stephanie Olson (@ExoStephO) July 18, 2021
Dog saliva contains iron porphyrins. Upon contact with oxygen, the iron is oxidized to iron oxide nanoparticles. Rust, essentially. This is why Olive and many other drooly dogs have rusty red staining by their mouths.
Demoralized by the cone, Olive slept awkwardly on her stomach, which isolated her saliva-soaked neck folds from the oxygen in my living room.
She was sedated and slept like a rock, but her saliva bacteria got to work. They quickly consumed all of the oxygen in her neck swamp, which prevented the red staining typically associated with dog saliva. Instead, green rust formed!
And the staining along her neck transitioned from rusty red on her chin to rusty green thanks to the combination of her unusually moist neck environment and sustained isolation from oxygen in the air—both symptoms of the cone.
Green rust is rare today because it is unstable in the presence of oxygen, but it may have been common on the ancient Earth before our atmosphere became oxygenated. The ocean may have even appeared green instead of blue 2.5 billion years ago!
So, geochemical friends: any ideas for how to safely remove green rust from dog fur? or any bets for how her fur color will change in the coming days?
Alternative hypothesis: Olive is actually short for Olivine, a famously green mineral, and she is just honoring her namesake.