The fascinating World of Extremophiles: What are they and Where to Find Them

Extremophiles are organisms that flourish in geochemically and physically extreme conditions, extremely low temperatures, and even the vacuum and radiation of outer space, as opposed to mesophiles that only thrive in temperatures between 20°C and 40°C or neutrophils that require neutral pH environments.

An exhibit, Life at the Limits, by the American Museum of Natural History is where you can learn about these organisms that thrive in extreme conditions.

Tardigrades, is an eight-legged micro-animals that live in water, resembles little fat piglets with vacuum-cleaner spout-like mouths, a.k.a. as moss piglets. First discovered by German pastor Johann August Ephraim Goeze in 1773, these miniscule creatures have astonished biologists.

A few years later, Italian naturalist Lazzarro Spallanzini, named them ‘tardi grada’ (slow-steppers), and provided the first description of the transformation tardigrades undergo under extreme environmental stress.

Tardigrades have been around for over 600 million years, with more than 1,000 species, and found across the globe, on land, where they cling to moss, lichens, and in fresh and sea water.

Common in moderate climates, they also thrive in places virtually no other lifeform can survive, such as Antarctica’s McMurdo Valleys, known as the driest and coldest desert on Earth.

Tardigrades have fascinating evolving ability, in order to survive when their habitats suffer a sudden water loss.

When their environment suddenly becomes inhospitable, they defy death by imitating it. Their metabolism winds down in a reversible process called cryptobiosis, literally means hidden life. In other words, the organism’s metabolic activities come to a reversible virtual standstill.

In 1776, Spallanzini described the dramatic change the organism undergoes in response to lack of water (anhydrobiosis).

The animal curls itself, tucking its head and eight limbs inside its body. It sheds over 95% of the water in its body, shriveling into a blob, known as a tun.

While shedding water, tardigrade produces sugar to protect its internal structures from fatal damage. Its metabolism slows down to less than 0.01% of normal activity as the animal virtually goes into stasis, until conditions improve. “Just add water, and these ‘barrels’ transform back into active ‘bears,’” the Museum wrote.

As tuns, tardigrades are virtually indestructible. Tuns were exposed by scientist to extremes temperature and pressure, toxic concentrations of gasses including carbon monoxide. In each case, the little animal rejuvenates to life as soon as water was resupplied.

Ten-foot models of tardigrades plus other incredibly resilient animals can be seen in the Life at the Limits exhibition at the American Museum of Natural History as from April 4th. Entrance is free for Members.

Imagine being able to hold your breath for 90 minutes, enduring temperatures above 300°F (149°C) and below -458°F (-272°C), or appear to cheat death by repeatedly cloning yourself.

Curator John Sparks, an ichthyologist (fish scientist), and Curator Mark Siddal, a parasitologist is overseeing the exhibit. It acquaints visitors to bizarre mating calls, incredible samples of parasitism and mimicry, and other odd means of survival, using specimens, interactive exhibits, videos and models.


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