From our Naturalist, Siena

Thought we were done with Lichens? Nope! We are back at looking at these fungal algae!

In today’s blog, we will be talking about some special microorganisms that can be found living on lichen all over the world. As was discuss previously, lichen are found virtually everywhere. The organism we will be talking about today is found literally everywhere.

Tardigrades, also lovingly known as Water Bears or Moss Piglets, are small microorganisms that are part of the Phylum Tardigrada. With more than 900 different species, these little organisms are some of the most diverse creatures in the world and can survive in some of the most extreme living conditions in our universe.

That’s right: Universe. Tardigrades have been found living on freezing icebergs in the arctic, on plants in the tropical rainforest, and, yes, on lichen around the world. They can even survive the vacuum of space. In order to be active, the tardigrades must be surrounded by water. This makes them classified as fully aquatic organisms even though they can be found in terrestrial environments like lichen and moss. Considering their size, only a film of water is needed to sustain these creatures. However, a thin film of water is prone to drying up or freezing, which can lead to the desiccation of the tardigrades in this film. Desiccation is a state of extreme dryness or the process of water removal. If the film of water dries up or freezes, these critters have ways of surviving!

In addition to surviving the absence of water, tardigrades can also withstand temperature extremes as low as -200°C and as high as 151°C. These micro-superheroes can also survive other environmental extremes like the intense pressures of the deep ocean, high levels of salinity, or even exposure to radiation 1000x the lethal human dose. It was for all of these reasons that, in 2007, NASA brought colonies of tardigrades on a mission to expose them to the most extreme condition there is: space.

The result of this endeavor? The tardigrades survived. However, this is not the only giant leap moss-piglet-kind has made! In 2019, tardigrades crash-landed on the moon as part of an Israeli spacecraft mission! While dehydrated, these moon-bears are probably still alive, considering tardigrades can survive years of desiccation! These micro-space explorers were even brought onto the International Space Station earlier this year! Lucky they don’t need to wear tiny spacesuits!

These tough organisms are incredible and can withstand conditions we never could; yet, these micro-cuties can be found right in your backyard! Below are some photos of a tardigrade that was living in some moss and lichen from Flat Rock Brook!