Why study DHABs?

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We didn’t even know DHABs existed until the 1980s, and life wasn’t found in them until the 1990s. Many—perhaps most—of the organisms found in DHABs had never been described by scientists before.

These organisms contribute to the cycling of carbon, nitrogen, sulfur, and other key elements in the Earth system. They can also tell us a lot about the very first forms of life on Earth. Most biologists agree that life probably arose in environments that had little or no oxygen, and that may have been hypersaline, as well—in other words, environments much like a modern-day DHAB. When we study DHAB microbes, perhaps we will see what very early forms of life looked like and how they lived.

DHAB organisms could also tell us something about extraterrestrial life. Hypersaline, low- or no-oxygen environments occur on other planets and moons. Could they be populated by microbes that resemble the organisms in DHABs? By expanding our understanding of how living things tolerate the extreme conditions in DHABs, we will have a better idea of where life can occur—and where we should look for it.