Catching dragons

Latitude: -65 17.6889 Longitude: -66 00.5287

The cruise is winding down, with only a few sampling days remaining. I remain inspired by the flexibility of our scientific leadership as best-laid plans go awry and amazed by the small projects my peers are completing in between sampling events. Scientists, as a rule, do not handle boredom well, and we have spent three months on this ship. There are brittlestar behaviors on video, sea urchin embryos painstakingly preserved, pterobranch zooids in tubes, and sea spiders walking …. slowly …. toward a camera. New collaborations were formed, new projects proposed, and I’m certain new ideas will continue to flow between this inspiring group. I came to Antarctica as somebody trained in sorting meiofauna, the animals that live between grains of marine sediment. I love the diversity of every petri dish; I’ve pulled out microscopic specimens from 18 PHYLA on this cruise! In my spare time, I got to know new species of one of my favorite phyla: Kinorhyncha, or mud dragons.

Kinorhynchs are entirely microscopic, which means they are often overlooked. They move through the sediment by puffing out their introvert, a spike-covered balloon surrounding their mouth that pushes sediment apart to allow their bodies to wiggle through. They are, in a word, bizarre. Naturally, I adore them. The hydro lab team loves some good mud. In my case, I take buckets of it and rather unceremoniously pour it back and forth in a technique known as “bubble and blot”. After sloshing the mud around really well (and usually getting a fair amount all over myself), I wait 15 minutes for the sediment to sink. Kinorhynchs are usually found stuck to the surface tension, held to the bubbles by their water-repellent outer cuticle. If you gently lay a piece of paper across the surface, and rinse it gently through a super-find net, you can catch the kinorhynchs without the mud! Like many techniques specific to certain taxa, it’s a bit more art than science.
Once I get the result into dishes, I get to go dragon hunting. I typically sort every petri plate twice: once thoroughly looking across the bottom of the plate, and one refocused to look at the surface tension instead. Picking up such small animals requires specialized equipment: I travel with Irwin Loops, microscopic bubble wand-like loops of wire on wooden handles that I can use to pick up kinorhynchs safely. This led me to a large number of kinorhynchs that look different than any I’ve ever seen. They have long spines down their back, and … well, if a kinorhynch can have a bad hair day, they’re having one. Is it a new species? Perhaps!

Identifying kinorhynchs at first glance appears no different from other animals: there is a dichotomous key that guides you through a “choose your own adventure” of physical traits. The process is more complicated because kinorhynchs are TINY. To key a kinorhynch, I have to mount a specimen. Not to a microscope slide (the slide itself is ten times thicken than the animal!), but between two delicate glass coverslips. This allows me to zoom all the way in on my microscope on both sides of the animal, the top and the bottom. The resulting “slide” is quite fragile, but thankfully, the ship has a 3-D printer so I was able to make some handy cover-slip-holders to bring my precious new specimens safety home.
​
So even on a day like today, when bad weather kept us from trawling, I have plenty of mud to bubble, and dragons to find. I add my microscopic favorites to the list of animals that we are getting to know in our spare time. And as I prepare specimens to ship across oceans to experts on the group, I sit here knowing that I may be the first person to ever see some of these animals. It’s not an uncommon occurrence when you study the overlooked meiofauna, but it’s an amazing feeling. 

Rebecca Varney
Ph.D. student in the Kocot lab
University of Alabama