On the eve of her arrival as an MBL Grass Fellow this summer, Tessa Montague of Harvard University is enjoying unexpected fame: Another video she took while a student in MBL Embryology has gone viral on Twitter. (Her first hit posting was about ctenophores.)
Tardigrades are extraordinary. They can survive -270 to +150 degrees celsius, ionizing radiation 100x higher than the lethal dose for humans and the vacuum of outer space.
— Tessa Montague (@TessaMontague) May 17, 2018
By Tessa Montague
MBL Embryology Course ’17
MBL Grass Fellow ’18
I captured this footage with a Zeiss Axioscope while I was a student in the MBL Embryology Course last summer. Bob Goldstein, a professor at University of North Carolina, Chapel Hill who studies these little animals, provided us with the tardigrades. I wanted to observe one under the microscope so I mounted the tardigrade on a slide and sealed a coverslip on top with light pressure, so the tardigrade could move its legs but couldn’t crawl out of the frame of view.
I noticed the large dark mass in the middle of the animal, but I assumed it was an organ. After crawling around for a few seconds, the dark mass started to move inside the tardigrade, and I was perplexed.
Then quite suddenly the whole thing was excreted, and I realized it was just a very large poo.
This video is sped up a little (the tardigrade, or water bear, moves at more of a bear’s pace), but the poop was still released surprisingly quickly. Bob Goldstein said he hadn’t seen a tardigrade poop before, so perhaps this is a rare treat. The video was captured using phase contrast microscopy, so it’s in black and white. In full technicolor, the poop is actually bright green, reflecting the tardigrade diet of lichens.