- Deep-Sea Bacteria Form Avatar-Style Electrochemical Networks
- Much-Touted Bloom Fuel Cell Still Too Spendy
- New High-Res Images of Luminous Star-Forming Region
- Brainy Crows Finally Stumped by Intelligence Test
- Chinese Scientists Say Losing Google Would Hurt Research
Posted: 24 Feb 2010 10:29 PM PST
According to findingsthat could have beenpulled from a deep-sea sequel to Avatar, bacteria appear to conduct electrical currents across the ocean floor, driving linked chemical reactions at relatively vast distances.
Noticed only when reseachers happened to test sediment leftovers from another experiment, the phenomenon may add a new mechanism to Earth's biogeochemistry.
"The cycling of elements and life at the bottom of the sea, and in soil, and anywhere else you're short of oxygen — this could help us understand those processes," said microbiologist Lars Peter Nielsen of Denmark's Aarhus University, co-author of the study, publishedFeb. 24in Nature.
The original focus of Nielsen's team wasn't seafloor conductivity, but an especially interesting species of sulfur bacteria found on the floor of Aarhus Bay. To help quantify their chemical activity, the researchers kept a few beakers of seawater and sulfur bacteria-free sediment for comparison.
After those experiments ended, the beakers were almost forgotten. Then, a few weeks later, the researchers noticed strange patterns of activity. Changing oxygen levels in water above the top sediment layer were almost immediately followed by chemical fluctuations several layers down. The distance was so great, and the response time so quick, that usual methods of chemical transport — molecular diffusion, or a slow drift from high to low concentration — couldn't explain it.
At first, the researchers were stumped. Then they realized the process made sense if bacteria in the top and bottom layers were linked. Anything that affected oxygen-processing bacteria up top would also affect the sulfide-eating microbes below. It would explain the apparent connection; and an electrical linkage would explain the speed. It would also boggle the mind.
"Such hypotheses would at one time have been considered heretical," wrote Kenneth Nealson, a University of Southern California microbiologist, in an accompanying commentary in Nature. A half-inch gap "doesn't seem like much of a distance. But to a bacterium it amounts to 10,000 body lengths, equivalent to about 20 kilometers (12 miles) in human terms."
In recent years, however,scientists have found species of microbes with outer membranes covered by electron-transporting enzymes, or studded with conductive, micrometer-scale filaments. These are used in driving experimental microbial fuel cells, and are known to be found in the Aarhus Bay mud. Those sediments also contain trace amounts of pyrite, an electrically conductive mineral.
The top sediment layer also had a low concentration of hydrogen ions, something that could only be explained through an electrochemical reaction, with electrons conducted from a distance, said Nielsen.
Nealson called the findings "astonishing," and said they "may be relevant to energy transfer and electron flow through many different environments." They could eventually applied to bacteria-based schemes for bioremediation, carbon sequestration and energy production.
Asked if he'd seen the blockbuster movie Avatar, with its storyline involving electrochemically linked forests that stored the inhabitants' souls in a planet-spanning biological computer, Nielsen said, "One of my colleagues saw this, and immediately sent me a message: 'You've discovered the secret of Avatar! Go see it!' The similarities are quite striking."
He continued, "I don't think there is much spirit in the networks we've seen here. It might be only about energy. But there are connections."
Image: At left, Nielsen measures current in the sediment sample; at right, a close-up view of the sediment. Credit: Nils Risgaard-Petersen
Citations: "Electric currents couple spatially separated biogeochemical processes in marine sediment." By Lars Peter Nielsen, Nils Risgaard-Petersen, Henrik Fossing, Peter Bondo Christensen & Mikio Sayam. Nature, Vol. 463, No. 7284, February 25, 2010.
"Sediment reactions defy dogma." By Kenneth H. Nealson. Nature, Vol. 463, No. 7284, February 25, 2010.
Posted: 24 Feb 2010 03:51 PM PST
A Silicon Valley startup that's taken more than $400 million in venture funding finally unveiled its product today in a star-studded extravaganza.
In an event held at eBay's headquarters in San Jose, California, Bloom Energy called on California Governor Arnold Schwarzenegger, Google co-founder Larry Page, and retired general Colin Powell to push their solid-oxide fuel-cell box, which converts natural gas or other fuels into electricity. The company says its "energy servers" produce 60 percent less carbon dioxide emissions than a coal-fired power plant, and cost less than electricity produced on the grid.
"This is like the Google IPO," said John Doerr, an investor in both Google and Bloom Energy with the legendary venture-capital firm Kleiner Perkins Caufield & Byers.
"This technology is fundamentally going to change the world," echoed Senator Diane Feinstein (D-California) during a promotional video shown at the press conference.
But is it really going to? Independent experts aren't so sure.
The analyst firm Lux Research posted a note to its blog today noting that Bloom had confirmed their 100-kilowatt boxes are priced between $700,000 and $800,000 without subsidies of any kind.
In fact, a long-term R&D collaboration between the Department of Energy and multiple solid-oxide fuel-cell manufacturers, the Solid State Energy Conversion Alliance, estimates that fuel cells will need to cost $700 per kilowatt of peak capacity to compete unsubsidized with the grid. Bloom's product costs 10 times that.
"The cost is about an order of magnitude higher than it needs to be, to be truly competitive," said Michael Tucker, a fuel cell scientist at Lawrence Berkeley National Laboratory.
When you do the math, the Bloom box's electricity costs substantially more per kilowatt hour than the grid.
"Without incentives, we calculate electricity would cost $0.13/kWh to $0.14/kWh, with about $0.09/kWh from system cost and about $0.05/kWh coming from fuel cost," Lux wrote. "Note that this is high compared to average retail U.S. electricity costs of roughly $0.11/kWh."
Right now, a 30 percent Federal government tax credit and a $2,500-per-kilowatt California subsidy for fuel cells substantially lowers the price of the machine for Bloom's customers. The company claims that with those incentives the life-cycle cost of electricity over 10 years could be as low as $0.08/kWh.
And over the next few years, it's probable that, like many technologies, the unit cost of Bloom's fuel cells will decrease as the scale of production increases, but it's unclear how cheap the Bloom boxes can get.
Tucker, for his part, does not think ceramic-based solid-oxide fuel cells can become competitive with the grid. That's why he's working on a stainless steel version that would be coated with a thin film of ceramic material.
Tucker said that from what he's heard, Bloom's product is similar to fuel cells from UTC, Kyocera and other companies.
"From an outsider's perspective, it sounds like their technology is relatively straightforward and similar to other technologies out there in this arena, but maybe their business approach is relatively unique," Tucker concluded.
This is business after all, and if marketing counts, Bloom Energy certainly has a leg up on its industrial competitors like Siemens.
"They are certainly going to raise visibility for the industry," Tucker said. "They are something of a PR leader in the market. If they can … ride that wave into an early market-share position, that could be huge. They will be getting experience with real-world customers."
Indeed, they are: The firm's beta testers include Walmart, Coca-Cola, Google and eBay.
Image: AP/Paul Sakuma
Posted: 24 Feb 2010 03:02 PM PST
Stars shine amidst a luminous, cotton-candy nebula in this new image of NGC 346, the largest star-forming region in our neighboring galaxy, the Small Magellanic Cloud.
The star cluster, located about 210,000 light-years away and measuring around 200 light years across, is home to a group of brilliant stars.
Many of the stars in the nebula are just a few million years old. These young suns were born when gusting winds from a massive star compressed a huge amount of matter, which then collapsed under its own gravity. The collapse created extremely dense hot spots that fueled the birth of new stars.
Light, wind and heat have whipped up gases in and around the cluster to form the pink-and-blue wispy cloud. Stars burning inside the nebula have made the surrounding gas hot enough to glow.
The new image was taken by the Wide Field Imager instrument on the 7.2-foot telescope at the at the La Silla Observatory in Chile. The image was captured using blue, violet and red filters, in addition to a narrow-band filter tuned to see the light emitted by hydrogen in gas clouds.
Posted: 24 Feb 2010 02:33 PM PST
Maybe they're not as smart as we thought: The New Caledonian crow, having passed so many other tests of animal cognition, has finally flunked an exam.
New Caledonian crows are valedictorians among corvids, a family of birds that includes ravens, jays and magpies. They've wowed scientists with their cognitive powers, even using wire as a food-fetching tool.
On one classic cognition test — retrieving a piece of food tied to a string — corvids perform so well that some researchers thought they didn't just learn through rote trial and error, but envisioned problems in their head.
In a study published Feb. 22 in Public Library of Science ONE, researchers added a twist: They ran the string through a hole in a plywood platform. Crows could only see the food when directly above the hole. When they pulled back on the string, they'd lose sight of it. If they really did have a mental image of the task, it wouldn't be a problem.
Twelve crows took the test: four who'd practiced on the old food-on-a-string setup, four who'd never seen it, and four who'd never seen it but could watch their reflection in a mirror.
Crows from the first group succeeded, but only after many attempts. Only one of the second group passed, also with difficulty. Two crows from the third group passed. It wasn't the ace performance usually seen in crows.
"These results are not consistent with the hypothesis that the crows built a mental scenario," wrote the researchers. "Our results raise the possibility that spontaneous string pulling in New Caledonian crows may not be based on insight but on operant conditioning mediated by a perceptual-motor feedback cycle."
In other words, the crows relied on a simple trial-and-error approach. But the researchers did acknowledge that their sample size was limited, and that depth perception could be skewed in a confusing way by the experimental setup.
If nothing else, the crows did far better than finches. And even if they're not good with spatial relationships, they're certainly fast learners.
Images: 1) New Caledonian Crows on the old experimental setup at left, and on the new apparatus at right. Credit: University of Auckland. 2) Schematic of the new test design. Credit: University of Auckland.
Citation: "An Investigation into the Cognition Behind Spontaneous String Pulling in New Caledonian Crows." By Alex H. Taylor, Felipe S. Medina, Jennifer C. Holzhaider, Lindsay J. Hearne, Gavin R. Hunt, Russell D. Gray. Public Library of Science ONE, Vol. 5 No. 2, February 22, 2009.
Posted: 24 Feb 2010 11:05 AM PST
Google and China may not be fighting over science, but their feud could have unintended negative consequences for researchers in the country.
A Nature News survey of Chinese scientists found that 84 percent of them thought losing access to Google would "somewhat or significantly" hurt their work process. Like their American counterparts, Chinese researchers use Google and Google Scholar to find papers and related information.
"Research without Google would be like life without electricity," one Chinese scientist told Nature.
In January, Google announced it would stop following censorship rules required by the Chinese government after its servers came under attack. It remains to be seen whether the Mountain View company will be thrown out of the country for that stance.
When Google's initial announcement broke, media blogger Robin Sloan of Snarkmarket pondered the possibility of the splitting of the famously world-circling internet.
"Is the Chinese internet going to be largely parallel? The othernet?" Sloan asked.
If events do continue in that direction, truly global enterprises like science could suffer as information becomes harder — even if only moderately — to exchange.
Image: AP Photo/Vincent Thian. A Chinese Google user presents flowers to the Google China headquarters in Beijing, Wednesday, Jan. 13, 2010.
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