10. Yellowstone's Hot Springs
From This Story
If you wanted to kill something, or maybe just dispose of a body, you couldn’t do much better than the conditions in Yellowstone’s hot springs. The springs are near the boiling point of water and acidic enough to dissolve nails. But some microbes thrive there, and the pigments they produce give the springs vivid, otherworldly colors.
The heat-loving bacteria Thermus aquaticus is the most famous Yellowstone microbe; it makes an enzyme that researchers use in genetics labs to make copies of DNA. Other Yellowstone microbes eat hydrogen, and a few years ago scientists there discovered an entirely new phylum of photosynthesizing bacteria.
Because there are so many hot springs and mud pots and geysers in Yellowstone, with a variety of temperatures and chemical compositions, the park hosts the greatest known diversity of archaea. Simple, single-celled organisms without nuclei, archaea are a branch of life that has been known only since the 1970s.
Many archaea thrive at hot temperatures (they are also found in volcanoes). And inside some Yellowstone archaea—just to complete the microbial ecosystem—are heat-loving viruses.
9. In Bodies Below the Freezing Point of Water
Some animals survive not only in environments below freezing, but in bodies below freezing. Spiders and insects produce antifreeze that prevent them from freezing solid. The larvae of certain Arctic flies can survive being chilled to about -76 Fahrenheit.
Many species of frogs, newts and turtles do freeze—more than 50 percent of the water in their bodies may be ice. The trick is that they carefully control where the ice forms. As the animal cools, its cells and organs squeeze out water and shrink. Only water outside of the animal’s cells freezes; the crystals may grow in between muscle fibers or around organs.
The coldest sustained body temperature in a mammal is about 27 degrees Fahrenheit, measured in Arctic ground squirrels. Their strategy is called “supercooling”—even though the fluid in their bodies is below the freezing point, the animals eliminate any material on which ice crystals could form.
8. Entirely Alone