Author: Ellie Livitsanou
Editors: Tharindi Jayatilake and Kira Tian
Artist: Allegra Williams
I know of a secret creature you probably have never heard of. They’ve been around for about 600 million years (beating dinosaurs by 200 million years!). They survive extreme heat, withstand extreme cold and live just about everywhere- from the coldest to the warmest climates. They can survive radiation, space, intense pressure, and EVEN 30 years without food or water. They have been revived from over 120 years ago! What are these practically invincible creatures? Take a guess! If you guessed tardigrades- you are correct! These creatures were discovered in 1773 by Johann August Ephraim Goeze, a German pastor, who described them as ‘’little water bears’’. Cute, right? But how do they survive?
In most conditions, tardigrades go into a state called cryptobiosis, during which they dehydrate themselves and curl up into a little ball, called a 'tun’, by putting away or retracting their ⟶ head and legs! By doing this, all their vital organs are covered by a sugary gel called trehalose (that protects membranes- also prevents any remaining water molecules from expanding from any surrounding heat) and their metabolic activity lowers to a shocking 0.01 percent of normal levels! That’s crazy! This state closely resembles death. Don’t be fooled, though. These little creatures are most certainly NOT dead. They are easily revived, though- just add some H2O. They come back to life in a matter of only a few hours.
Tardigrades also produce a lot of antioxidants that have been found to be another way of protecting their vital organs! As well as producing antioxidants, they also provide a protein that shields their DNA from harmful radiation! So tiny, (usually around only 1mm long!), yet so mighty!
When in water, they bring out ANOTHER perseverance mechanism. When the water around them is low on oxygen, they will increase their length by stretching out so that their metabolic rate can reduce, so that they use less oxygen. While in this state, their muscles take in water and oxygen at a satisfactory amount- just enough so that they can survive.
Tardigrades have been around for 600 million years already, and will likely survive much longer than we will. Studies, conducted by scientists researching at Harvard and Oxford University, found that Tardigrades could survive after humanity is long gone. They looked at the likelihood of some astronomical events, including gamma-ray bursts, supernova blasts not too far away from earth as well as asteroids that could potentially land on earth. Don’t worry, though- us humans will most likely not be here as a species to live through it. We’re talking over the next few BILLIONS of years. That’s a long way away, and, most likely, tardigrades will still be here as a species. They proceeded to look at the probability of these catastrophic events wiping out the most strong species on Earth. While humans will probably be wiped out as a species, tardigrades most definitely will survive most. (Study was published in July 2017 in the Journal Scientific Reports).
Quotes from the researchers:
"To our surprise, we found that although nearby supernovas or large asteroid impacts would be catastrophic for people, tardigrades could be unaffected,” "Therefore, it seems that life, once it gets going, is hard to wipe out entirely. Huge numbers of species, or even entire genera may become extinct, but life as a whole will go on." -statement made by David Sloan, researcher and co-author of a study conducted at Oxford University.
Citations:
Bradford, Alina. “Facts About Tardigrades.” LiveScience, Future US, 14 July 2017,
www.livescience.com/57985-tardigrade-facts.html.
“Tardigrade.” National Geographic, National Geographic Society,
www.nationalgeographic.com/animals/invertebrates/t/tardigrades-water-bears/.
Fox-Skelly, Jasmin. “Earth - Tardigrades Return from the Dead.” BBC, BBC, 13 Mar. 2015,
www.bbc.com/earth/story/20150313-the-toughest-animals-on-earth.
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