Dormant desert life hints at possibilities on Mars

Updated 27 February 2018
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Dormant desert life hints at possibilities on Mars

MIAMI: It may rain once a decade or less in South America’s Atacama Desert, but tiny bacteria and microorganisms survive there, hinting at the possibility of similar life on Mars, researchers said Monday.
The desert, which spans parts of Chile and Peru, is the driest non-polar desert on Earth and may contain the environment most like that of the Red Planet, said the report in the Proceedings of the National Academy of Sciences.
Lead researcher Dirk Schulze-Makuch, a professor and planetary scientist at the Technical University of Berlin, and colleagues took a trip to the desert in 2015 to learn more about what kind of life might exist there. Then, unexpectedly, it rained.
Scientists detected an explosion of biological activity in the soil, and quickly began using sterile spoons to scoop up samples.
Genomic analyzes helped identify the several apparently indigenous species of microbial life — mostly bacteria — that had somehow adapted to live in the harsh environment by lying dormant for years, then re-animating and reproducing once it rained.
“In the past, researchers have found dying organisms near the surface and remnants of DNA, but this is really the first time that anyone has been able to identify a persistent form of life living in the soil of the Atacama Desert,” Schulze-Makuch said.
“We believe these microbial communities can lay dormant for hundreds or even thousands of years in conditions very similar to what you would find on a planet like Mars and then come back to life when it rains.”
Scientists returned to the Atacama in 2016 and 2017 for follow-up visits and discovered that the same microbial communities in the soil were gradually reverting to their dormant state.
But they did not completely die off. Single-celled organisms, found mainly in the deeper layers of the desert, “have formed active communities for millions of years and have evolved to cope with the harsh conditions,” said the PNAS report.
Since Mars had oceans and lakes billions of years ago, researchers say early life forms may have thrived there, too.
The world’s space agencies are sending robotic vehicles to Mars in a bid to uncover signs of life, but any attempt to return samples to Earth will be costly and complicated.
Schulze-Makuch said the research may help scientists home in on ways to study Martian microbes, which might have evolved to the planet’s colder, drier climate over time, much like the Atacama microbes.
“We know there is water frozen in the Martian soil and recent research strongly suggests nightly snowfalls and other increased moisture events near the surface,” he said.
“If life ever evolved on Mars, our research suggests it could have found a subsurface niche beneath today’s severely hyper-arid surface.”


YouTube, under pressure for problem content, takes down 58 mln videos in quarter

Updated 14 December 2018
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YouTube, under pressure for problem content, takes down 58 mln videos in quarter

  • Google added thousands of moderators this year, expanding to more than 10,000, in hopes of reviewing user reports faster

WASHINGTON: YouTube took down more than 58 million videos and 224 million comments during the third quarter based on violations of its policies, the unit of Alphabet Inc’s Google said on Thursday in an effort to demonstrate progress in suppressing problem content.
Government officials and interest groups in the United States, Europe and Asia have been pressuring YouTube, Facebook Inc. and other social media services to quickly identify and remove extremist and hateful content that critics have said incite violence.
The European Union has proposed online services should face steep fines unless they remove extremist material within one hour of a government order to do so.
An official at India’s Ministry of Home Affairs speaking on the condition of anonymity on Thursday said social media firms had agreed to tackle authorities’ requests to remove objectionable content within 36 hours.
This year, YouTube began issuing quarterly reports about its enforcement efforts.
As with past quarters, most of the removed content was spam, YouTube said.
Automated detection tools help YouTube quickly identify spam, extremist content and nudity. During September, 90 percent of the nearly 10,400 videos removed for violent extremism or 279,600 videos removed for child safety issues received fewer than 10 views, according to YouTube.
But YouTube faces a bigger challenge with material promoting hateful rhetoric and dangerous behavior.
Automated detection technologies for those policies are relatively new and less efficient, so YouTube relies on users to report potentially problematic videos or comments. This means that the content may be viewed widely before being removed.
Google added thousands of moderators this year, expanding to more than 10,000, in hopes of reviewing user reports faster. YouTube declined to comment on growth plans for 2019.
It has described pre-screening every video as unfeasible.
The third-quarter removal data for the first time revealed the number of YouTube accounts Google disabled for either having three policy violations in 90 days or committing what the company found to be an egregious violation, such as uploading child pornography.
YouTube removed about 1.67 million channels and all of the 50.2 million videos that were available from them.
Nearly 80 percent of the channel takedowns related to spam uploads, YouTube said. About 13 percent concerned nudity, and 4.5 percent child safety.
YouTube said users post billions of comments each quarter. It declined to disclose the overall number of accounts that have uploaded videos, but said removals were also a small fraction.
In addition, about 7.8 million videos were removed individually for policy violations, in line with the previous quarter.