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Meet Five Microbes That Hitched a Ride on the Mars Rover

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Before any nation launches a spacecraft, the U.N.’s Outer Space Treaty requires the craft to undergo extensive cleaning, to “avoid harmful contamination of space and celestial bodies.” Basically, we don’t want our gross Earthly microbes to invade new regions of space and kill off other life that might potentially be living there. That’s especially true for Mars, because scientists think there’s a chance that single-celled organisms may have evolved there in the past, and might even still live on the Red Planet today.

NASA spacecraft get disinfected about 10 to 30 times before they launch, says Stephanie Smith-Rohde from the University of Idaho. But those decontamination sessions can’t catch everything. Smith-Rohde and her colleagues analyzed swabs that were taken from the surface of the Curiosity rover after cleaning and prior to launch. Their preliminary results, which were presented at a meeting of the American Society for Microbiology, turned up 377 organisms from 65 bacterial species.

Smith-Rohde’s team attacked these microbes with a battery of tests meant to simulate the harsh conditions of space and Mars, and they found that many of the microbes survived just fine—even, surprisingly, the bacteria that don’t form protective spores.

Scientists need to do longer-term studies, but so far the evidence suggests that some of these bacteria may have been capable of surviving a journey to Mars.

“Have we contaminated Mars already, or is there no way those microbes could survive the journey?” asks Smith-Rhode. “We don’t have answers to those questions yet. These studies allowed us to narrow down the organisms that we want to focus on.”

If Earth microbes did make it to Mars, here are the ones that are most likely to make themselves at home.

1. Staphylococcus

These bacteria (top), typically found in soil and on human skin, persevered in petri dishes that contained 20 percent salt. That’s really salty—by comparison, the ocean is only about 3 percent salt. It may be that Staphylococcus could also thrive in Mars’ salty sands and waters.

2. Enhydrobacter

During laboratory tests, Enhydrobacter colonies withstood a 2000-joule zap of radiation, “which is a pretty decent dose of UVC radiation,” says Smith-Rohde. They also endured a two-week desiccation experiment, wherein they had absolutely no access to water, with no major problems.

3. Moraxella

Nearly 50 percent of Moraxella bacteria outlived a one-hour dunk in a 5 percent hydrogen peroxide solution—a common cleaning agent meant to kill microbes on spacecraft.

4. Streptomyces

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Normally noted for their role in decaying organic matter, Streptomyces microbes are surprisingly hardy. In experiments, they were able to grow in the 20 percent salt solution as well as the two-week desiccation period, withstood low temperatures, and tolerated a pH of 9—similar in acidity to the soils of Mars.

5. Gracilibacillus


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Gracilibacillus one of a handful of types of bacteria that can eat the perchlorates found in Martian soil. “Gracilibacillus would definitely be a top contender to survive on Mars,” says Smith-Rohde.

Up next, Smith-Rohde and her colleagues plan to learn more about each of these microbes. They will expose the hardiest species to multiple extreme conditions at once, which is more like what they’d really experience in space, and also may determine whether they could endure the nine-month journey to Mars.

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London's Sewer-Blocking 'Fatbergs' Are Going to Be Turned Into Biodiesel
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UK officials can't exactly transform the Whitechapel fatberg—a 143-ton trash mass lurking in London's sewer system—into treasure, but they can turn it into fuel. As The Guardian reports, Scottish biodiesel producer Argent Energy plans to convert parts of the noxious blockage into an environmentally friendly energy source.

For the uninitiated, fatbergs (which get their names from a portmanteau of "fat" and "icebergs") are giant, solid blobs of congealed fat, oil, grease, wet wipes, and sanitary products. They form in sewers when people dump cooking byproducts down drains, or in oceans when ships release waste products like palm oil. These sticky substances combine with floating litter to form what could be described as garbage heaps on steroids.

Fatbergs wash up on beaches, muck up city infrastructures, and are sometimes even removed with cranes from sewer pipes as a last resort. Few—if any—fatbergs, however, appear to be as potentially lethal as the one workers recently discovered under London's Whitechapel neighborhood. In a news release, private utility company Thames Water described the toxic mass as "one of the largest ever found, with the extreme rock-solid mass of wet wipes, nappies, fat and oil weighing the same as 11 double-decker buses."

Ick factor aside, the Whitechapel fatberg currently blocks a stretch of Victorian sewer more than twice the length of two fields from London's Wembley Stadium. Engineers with jet hoses are working seven days a week to break up the fatberg before sucking it out with tankers. But even with high-pressure streams, the job is still akin to "trying to break up concrete," says Matt Rimmer, Thames Water's head of waste networks.

The project is slated to end in October. But instead of simply disposing of the Whitechapel fatberg, officials want to make use of it. Argent Energy—which has in the past relied on sources like rancid mayonnaise and old soup stock—plans to process fatberg sludge into more than 2600 gallons of biodiesel, creating "enough environmentally friendly energy to power 350 double-decker Routemaster buses for a day," according to Thames Water.

"Even though they are our worst enemy, and we want them dead completely, bringing fatbergs back to life when we do find them in the form of biodiesel is a far better solution for everyone," said company official Alex Saunders.

In addition to powering buses, the Whitechapel fatberg may also become an unlikely cultural touchstone: The Museum of London is working with Thames Water to acquire a chunk of the fatberg, according to BBC News. The waste exhibit will represent just one of the many challenges facing cities, and remind visitors that they are ultimately responsible for the fatberg phenomenon.

"When it comes to preventing fatbergs, everyone has a role to play," Rimmer says. "Yes, a lot of the fat comes from food outlets, but the wipes and sanitary items are far more likely to be from domestic properties. The sewers are not an abyss for household rubbish."

[h/t The Guardian]

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Does Self-Control Deplete Over the Course of the Day? Maybe Not, Says New Study
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For months now, I’ve been trying to cut out sugar from my diet. I’ve read about all the ways my sweet tooth will be the death of me, and I’ve resolved to give it up. And yet, even as I write this, my long-term goal to eat healthy is losing out to my eternal desire to eat M&Ms at my desk. Is it because it’s the end of the day, and I’ve been trying to make choices for eight hours already? Or is it something else?

A new study in PLOS One pushes back on the popular theory known as "ego depletion," which hypothesizes that self-control is a finite resource that depletes throughout the day, much like energy levels. Instead, researchers from the University of Toronto and the learning technology company Cerego found that people's self-control depletes when it comes to doing one task for a long period of time, but that self-control fatigue isn't a factor when you're switching tasks. In other words, it's hard to say no to the box of cookies all day long, but saying no to the box of cookies won't impede other acts of self-control, like your ability to focus on your homework instead of turning on the TV.

The study used data from Cerego, which publishes online study materials, examining the study behaviors of two groups of college students using the Cerego system as part of semester-long psychology courses. The researchers looked at data from two groups of users, one group of 8700 students and one of almost 8800, focusing on how long they worked during each session and how well they performed at the memory tests within the curriculum.

If self-control really is a finite resource, it should be depleted by the end of the day, after people presumably have spent many hours resisting their first impulses in one way or another. But the researchers found that this wasn't true. Overall, students didn't do any better if they used the program earlier in the morning. Instead, performances peaked around 2 p.m., and people logged in to use the software more and more as the day went on, suggesting that the motivation to learn doesn't fall off at night (though that may also be because that's when college students do their homework in general).

However, mental resources did seem to be drained by doing the same task for a long period of time. The researchers found that after a certain point, students' performance dropped off, peaking at about 28 minutes of work. They made about 5 percent more mistakes 50 minutes into the session compared to that peak.

When it comes to the idea that we exhaust our store of self-control, the authors write, "the notion that this fatigue is completely fluid, and that it emerges after minutes of self-control, is under considerable doubt."

The notion of ego depletion comes from a 1998 study in which researchers asked participants to hang out in a room full of fresh-baked cookies, telling them to eat only from a bowl of radishes, leaving the cookies untouched. Then, those volunteers worked on an impossible puzzle. Volunteers who had spent time avoiding the delicious pull of cookies gave up on the mind-boggling task an average of 11 minutes earlier than a group of volunteers who were brought into the same room and allowed to eat as many cookies as they wanted. (Lucky them.)

Since then, the idea has taken off, leading to hundreds of subsequent studies and even influencing the habits of people like Barack Obama, who told Vanity Fair in 2011 that he only wore blue or gray suits in order to cut down on the non-vital decisions he had to make throughout the day.

This current study isn't the first to challenge the theory’s veracity, though. In 2016, a 2000-person replication study by some of the same authors (with scientists in 23 different labs) pushed back on the theory of ego depletion, finding that short spurts of self-control didn't have any effect on subsequent tasks. This study just adds to the evidence against the well-established idea.

So it's looking more and more like ego depletion isn't a good excuse for my afternoon vending-machine habit. Perhaps the true secret to excellent self-control is this: Just be a raven.

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