Extremophiles
Extremophiles are microscopic organisms that thrive in that could be described as extreme conditions. In Yellowstone, these conditions can include extreme heat or an altered pH—either very low pH (acidic), very high pH (alkaline), or a combination of heat and altered pH The environments of extremophiles would kill other organisms. However, if their environment would change to conditions that we would consider more hospitable, the extremophiles would perish. Extremophiles are a type of microorganism, a small living thing that cannot be seen without a microscope. However, colonies, or large groups of microorganisms living together, are visible in many of Yellowstone’s thermal features. |
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Extremophiles in Yellowstone fall into two categories:
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Let us review what pH measurements mean; pH is a scale of acidity and alkalinity ranging from 1 to 14, with a pH of 7 indicating neutral, neither acidic nor alkaline. Any pH below 7 is considered acidic; anything above is alkaline or basic. A substance with a pH close to 1 would be a powerful acid; a pH close to 14 would be highly alkaline. To better appreciate the impact of pH, comparing the conditions in Yellowstone’s thermal features to those tolerated by humans may be helpful. In the human body, our normal pH is 7.35 to 7.45. A pH above 7.8 or below 6.8 is generally fatal. Our pH may vary slightly from 7.35 to 7.45 during the day, but only by minute amounts. |
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Other extremophiles found throughout the world includes:
“Normal” microorganisms are called mesophiles. They grow best in temperatures between 50° to 122° F (10° to 50° C). |