by Rebecca Dang
Water droplets are beautifully shaped spheres of transparent liquid unlike any other substance on Earth. To the naked human eye, we see a colourless small sphere of water. We might not suspect that water droplets are home to millions of microscopic organisms like roundworms, rotifers, and tardigrades living beneath the surface of the water.
Tardigrades are tiny, transparent, and unfamiliar microscopic organisms. They are often referred to as water bears because of their legs, claws, and bear-like movement in the water (Image 1). Tardigrades commonly live in habitats rich in soil, moss, and lichen. But any wet surface in nature could be crawling with the organisms. Even in dramatically contrasting climates like Antarctica and Japan, different species of tardigrades have been discovered. Therefore, tardigrades may be covering every corner of the world. However, many people do not know that tardigrades exist.
For Holly Dunderdale, a Biology and Earth Science teacher at Marion High School in Illinois, tardigrades are handy organisms for teaching the scientific method. In 2018, Dunderdale facilitated a project funded by The Robert Noyce Teacher Scholarship Program to help sophomore biology students engage in the scientific process by performing their experiments and collecting their own data.
Students collected damp moss and lichen samples from various sites in Southern Illinois while documenting details such as habitat location on their bag label (Image 2). Then, the students soaked the samples in water to suspend the tardigrades in the solution and identified tardigrades under a microscope back in their classrooms.
“Students enjoyed seeing little [tardigrades] moving and knowing that they could find one that nobody else maybe had found. I, as a teacher, walked away knowing that they were learning about the scientific research process, how to collaborate with each other, and had to work on their microscope skills”, said Dunderdale.
The project was completed two years ago, but Dunderdale enthusiastically reassures that this would be a worthwhile activity for students now—especially with the global COVID-19 pandemic that has challenged how students receive their education. The transition to online learning helps to deliver educational content but has simultaneously hindered opportunities for science students to gain technical hands-on experience.
Because tardigrades are relatively easy to find in various outdoor spaces, conducting experiments with them is more feasible for at-home learners. “It would be so easy, just getting them to get to that point where they could find them, be patient enough to find them”, said Dunderdale. Furthermore, using a paper microscope similar to a Foldscope would be a cheaper alternative to using expensive microscopes. Engaging students to gain practical hands-on skills outdoors will connect them to nature and ignite their curiosity.
In addition to being a teaching organism, tardigrades are ideal for research exploration because they can be grown inside laboratories. Tardigrades have also impacted the scientific world by contributing to space and medical research. Yet, there are not many published articles examining their life traits and how tardigrades adapt to the laboratory environment.
A study from McMaster University highlighted some life traits of a tardigrade species called Hypsibius exemplaris under laboratory conditions. The scientists examined various life traits including body growth, reproduction success, and lifespan. According to the authors of the study, it is important to understand how tardigrades adapt to laboratory conditions as a fundamental step for current and future research studies.
“As with any organism that is used for formal scientific investigation or experimental research, in a laboratory setting, an investigator or researcher must establish a baseline life history for reference”, said Jonathon Stone, an Associate Professor in the Department of Biology at McMaster University. The term baseline refers to the starting point or initial measurements taken under normal conditions. These measurements are needed because they are used to compare the results from experiments where variables are manipulated by scientists.
Understanding how tardigrades live and adapt to the laboratory conditions is essential, not only for future research but to ignite interest in the next generation of scientists. The findings from basic science research can be a useful resource for students who want to conduct their own tardigrade experiments in their backyards.
Even for Stone, his first experience with tardigrades as a graduate student was an exceptional moment. “My supervising professor returned to the laboratory one Monday morning with rocks,” he recalls, “some covered in moss and some covered in lichens, which had been collected in eastern Ontario. We soaked the rocks in water to awaken the critters, and I became smitten.”
Rebecca completed her Master’s degree in Pathology and Laboratory Medicine at Western University. Currently, she is pursuing a career as a freelance science writer, where she writes about a wide range of scientific fields from pedagogy to medical research.