Blogs / 80beats

Almost two miles beneath the earth’s surface in a South African goldmine, researchers have found a new species of bacteria that lives in total isolation from any other organism. The discovery offers the first known example of an ecosystem that isn’t a complex web of different life forms, but is instead hosts just one self-sufficient species. The bacteria, Desulforudis audaxviator, is able to extract all its food and energy directly from the surrounding water and rocks, and researchers say the independent microbe offers a glimpse of the shape life could take on other planets.

Researchers wanted to know what organisms were living in the mine’s deep fissures, a habitat completely devoid of light and oxygen, so they analyzed the genes present in a water sample to determine what species lived there. They filtered a total of 5,600 liters of mine water to get their sample, which gave other microbes plenty of opportunities to make themselves known. Of the DNA sequences obtained from this sample, over 99.9 percent were from this single species; over half of the remainder were obvious contaminants from their own lab [Ars Technica].

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Marine biologists have gotten the first footage ever of a school of fish living 4.8 miles beneath the ocean’s surface in the cold, pitch black, and fiercely pressurized habitat of the Pacific’s Japan Trench. A video shows the pale white hadal snailfish, officially known as Pseudoliparis amblystomopsis, happily wriggling around on the seabed, despite water pressure that the researchers say is equivalent to 1,600 elephants standing on the roof of a Mini.

The fish belong to a species previously known only from five pickled specimens trawled up by Russian scientists in the 1950s, said [researcher] Monty Priede [National Geographic News]. Priede’s team of British and Japanese researchers found the rare snailfish during their exploration of deep, narrow marine trenches in Pacific Ocean, and say it was the deepest ever sighting of live fish.

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Tiny invertebrates known as water bears are in one sense far tougher than humans who can crush hundreds of them underfoot: A new study has shown that the water bears can survive the vacuum and radiation of space. The water bears, who are more properly known as tardigrades, were launched into orbit aboard a European Space Agency satellite, where they were exposed for 10 days to the cold, low pressure, and intense radiation of space before being brought back down to Earth to study.

Researchers already knew that water bears were unusually tough critters. [T]hey prefer to spend their days in water, perhaps on a beach or a dewy patch of moss. But when the water dries up, the millimetre-long ‘bears’ can contract into a dried-out state and survive like that for years. They are also one of the few animals that survive year-round on continental Antarctica, and are among the most radiation-resistant animals known [Nature News].

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In a salty hot spring near Mono Lake, California, researchers have found two new species of bacteria that use arsenic for photosynthesis, and require no oxygen to fuel the process. Researchers say the bacteria may be similar to those that existed on primordial Earth where oxygen was scarce, and may illustrate an important stage of how early life developed in mineral-rich waters over 2 billion years ago.

Arsenic is well-known for its toxicity; it was used so often as tool for homicide in the 1800s that it earned the nickname “king of poisons” [The Scientist]. Yet the newly discovered bacteria can not only tolerate the element, they require it to survive. One of the first steps most organisms perform in photosynthesis is to split water molecules, creating oxygen. Oxygen donates energy in the form of electrons to other molecules, setting off a chain reaction that eventually results in the building of sugars for the organism’s own food. For the red and green bacteria found in Mono Lake, arsenic plays the role of oxygen [Science News].

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Just when the world is abuzz about the possibility that the Mars Phoenix Lander will find evidence of liquid water and life-enabling conditions in the prehistoric Martian past, a new report throws a bucket of salty water on that enthusiasm.

Researchers studied geochemical findings from the Mars rover Opportunity, and now say that even if liquid water did exist on Mars in a warmer era in the planet’s history, it was probably too salty to support life — or at least, life as we know it.

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