Note: This column was published in the Barrow Journal on Wednesday, October 8, 2014.
My family and I have been enjoying watching the new Cosmos: A Spacetime Odyssey, which is a documentary series that explains the principles upon which science is based. It’s a follow-up to Carl Sagan’s 1980 series Cosmos: A Personal Voyage. It uses storytelling and special effects such as Sagan did in the first series, but it’s all updated, and it’s a beautiful show.
In the second episode my family learned about tardigrades, and my eight-year-old became very excited. Tardigrades, or “water bears,” have to be one of the most amazing creatures on earth, and they are everywhere, but my family had no knowledge of them until now. This is because they are only .5mm – 1.2mm in length. They are big enough to see under a low-power microscope, but not big enough to notice when we’re walking through the woods on one of our hikes.
What is amazing about tardigrades is that they can live in conditions that would kill most other living creatures on earth. They can live in freezing temperatures (just above absolute zero) or in boiling water. They can withstand pressures that are far greater than that of the deepest trenches in the ocean. They can go up to ten years without food or water, and they have survived the vacuum of outer space. Because of these abilities, they have survived all five of Earth’s mass extinctions.
Their secret is cryptobiosis, which slows down the tardigrade’s metabolic processes. Without water, according to wired.com, “it can dehydrate to 3 percent of its normal water content in what is called desiccation, becoming a husk of its former self.” When you add water, they come back to life.
See why we were amazed to learn about these tiny creatures? My eight-year-old looked them up online, so we were able to view some photos and film taken of them under high-powered microscopes. We read more about them, and we also learned that it’s easy to find tardigrades in our backyard, so my son wanted to do that too.
We learned in Cosmos that they live in moss or lichen, but according to the Science Education Resource Center at Carleton College (SERC), tardigrades can be found almost everywhere. The center also said there are over 900 described species (though I have read over 1,500 species on another site), and they have been found in the mountains, ocean, rain forests and the Antarctic. That site also mentions that “Live tardigrades have been regenerated from dried moss kept in a museum for over 100 years!”
First my son wanted to gather some moss in the backyard, which we did, and we looked at it under our microscope – no tardigrades. So then he wanted to look up “what is the best kind of moss to find tardigrades in.” We tried that and found something more helpful – complete instructions on how to find and care for tardigrades.
We learned that we would probably have a better chance of finding tardigrades in lichen and that once you get a sample, you need to soak it in distilled or rain water for several hours or overnight. My son gathered some moss and two small containers of lichen and let it soak in rainwater for 24 hours.
The next day my eight-year-old wanted to look at the moss water first. You’re supposed to squeeze out the moss and then put the water in a shallow dish such as a petri dish and then spend about 15 minutes looking at it under the microscope.
We found nothing in the water with the moss, but when we looked at the water with the lichen, we found some tardigrades almost immediately.
We were surprised to see that they are translucent. What we saw was a reddish outline around their body. We could make out their eight legs, but we couldn’t see the claws. We also saw their tubular mouth. My son said they looked like little, chubby caterpillars to him.
We also found all sorts of other wiggly things in there too! We haven’t identified those other creatures yet, but I think one is a nematode, which looks like a worm, and tardigrades prey on them.
I left the microscope and the tardigrades on our table so that my son can observe them for a few days before we release them back into the yard. My son is fascinated with the microscopic life in this tiny dish, and now he says he wants to learn more about bacteria. You never know where this might lead.