- 8-Year-Olds Publish Scientific Bee Study
- Black Ghost Knifefish Robot Unmasks Movement Secrets
- Acidifying Oceans Could Upset Life’s Nitrogen Cycles
- Reader Photos: Lunar Eclipse Solstice Special
- One-Fourth of DNA Born by 2.8 Billion Years Ago
Posted: 21 Dec 2010 04:31 PM PST
A group of British schoolchildren may be the youngest scientists ever to have their work published in a peer-reviewed journal. In a new paper in Biology Letters, 25 8- to 10-year-old children from Blackawton Primary School in the UK report that buff-tailed bumblebees can learn to recognize nourishing flowers based on colors and patterns.
"We discovered that bumblebees can use a combination of colour and spatial relationships in deciding which colour of flower to forage from," the students wrote in the paper's abstract. "We also discovered that science is cool and fun because you get to do stuff that no one has ever done before."
The paper itself is well worth reading. It's written entirely in the kids' voices, complete with sound effects (part of the Methods section is subtitled, "'the puzzle'…duh duh duuuhhh") and figures drawn by hand in colored pencil.
The project, which began three years ago, grew out of a lecture neuroscientist Beau Lotto of University College London gave at the school, where his son Misha was a student. Lotto spoke about his research on human perception, bumblebees and robots, and then shared his ideas on how science is done: "Science is nothing more than a game."
"Nature's way for us to discover patterns and relationships is to play. That's the same aim that science has," Lotto said. "I think everyone does science every day. The scientific process is part of life."
After the talk, Lotto and Dave Strudwick, Blackawton Primary School's head teacher, decided to try to do an original research project with the students where the kids would have full control. Lotto also ran a scientific outreach program called Street Science, whose aim was to get non-scientists to do original experiments outside of the lab. He and Strudwick wondered if the same idea would work in a classroom.
"It's so different from other science education programs, where the aim is to learn facts," Lotto said.
Over the course of about two months, Strudwick and Lotto got the kids thinking about what questions interested them, and how they could solve those questions through puzzles or games. Eventually they focused their questions on bumblebees.
"If you want to ask a question of a bumblebee, you have to put yourself in the perspective of bumblebees," Lotto said. "So we had a day of being bumblebees."
Some of the initial questions were silly: Could bees learn to play Monopoly? What about soccer? But several questions, such as "Could bumblebees learn to associate color with heat?" had been addressed in scientific papers in the last 10 years, Lotto said.
Ultimately the class decided to investigate whether bees could use spatial relationships between colors to figure out which flowers had sugar water in them, and which didn't. The question has interesting implications for bees in the wild, the kids pointed out. If some flowers are bad or have already been sucked dry of nectar, bees should learn to avoid them, "which is like a puzzle."
The students helped set up a Plexiglas bee hutch in a church near the school, and designed a series of puzzles for the bees to solve. In the first puzzle, the students set up an array of yellow and blue lighted circles at the end of the bee arena.
The circles were arranged such that half the time, four blue circles were surrounded by twelve yellow circles, and half the time the colors were swapped. Only the circles in the center had sugar water. In some trials, the outside circles had salt water.
"We did this so that they would learn not to go just to the colours, but had to learn the pattern," the students wrote. "Otherwise they might fail the test, and it would be a disaster."
After a learning trial in which the bees overwhelmingly chose the sugar-bearing "flowers," the students took the sugar water away to see if the bees would still go for the previously rewarding circles. The bees chose right 90.6 percent of the time, the kids reported.
The students then designed follow-up experiments to try to understand how the bees chose correctly. They built a similar setup with green flowers in the center to see if the bees used spatial patterns and ignored color. Most of the bees seemed confused and chose randomly, but two went straight to the green, central flowers.
Their finding is "novel, but not earth-shattering," Lotto said. Several independent reviewers "came back saying this is all sound," he added. "This is a unique finding, and the methods are as they should be."
"The data as they presented it is compelling," said psychologist Laurence Maloney of NYU, who wrote a commentary on the paper. "It's a very impressive performance by a group of students of that age. I wouldn't have thought they could do it."
Maloney found the fact that different bees seemed to take different strategies was intriguing from an evolutionary perspective.
"You could imagine one of the strengths of natural selection is that everyone has a slightly different strategy, and when presented with a problem, someone's strategy turns out to be the right one," he said. "It just gives me the chills to look at this kind of intelligence and know that it came about because of random choices between different individual animals."
Strudwick and Lotto faced some challenges getting public recognition for their students' work. They initially tried to get outside funding for the project, but were rejected.
"One of the referees said the kids couldn't do it. The other said it wasn't high enough cost-to-benefit ratio," Lotto said. "That just added fuel to fire."
Getting the paper published was a struggle as well. In particular, several journals got stuck on the fact that the paper doesn't cite any references. Lotto says they left the references out because the historical context wasn't what inspired the kids, anyway.
"That wasn't the basis for doing the experiment, it was what was interesting to them. That's the driver of any quality science study," Lotto said. "That's what I tell my PhD students: Don't do any reading. Figure out why you wake up in the morning, what you're passionate about, and then read the literature. But don't figure out what's interesting based on what other people say."
Strudwick says the project has completely changed the way Blackawton Primary School approaches science education, and that the students have a much more positive view of science now than three years ago. The students' scores on Britain's national science exams are well above average, too.
Misha Lotto, now 10, says his view of science changed thanks to the bees.
"I thought science was just like math, really boring," he said. "But now I see that it's actually quite fun. When you're curious, you can just make up your own experiment, so you can answer the question."
Some of the students now want to be scientists when they grow up, but some still want to be soccer players and rock stars. That's okay, Lotto says.
"If they don't turn out to be scientists, that's not a big deal," he said. "The hope is that this kind of program doesn't just create data and information and little scientists. Being uncomfortable with uncertainty, in fact being excited about not knowing — that's really what we're trying to foster through science."
Lotto and Strudwick are now developing a similar program called "i,scientist" at the Science Museum in London, where visitors and classes from nearby schools can do real experiments on-site. Strudwick hopes to help other schools develop their own student-driven science experiments.
"I certainly don't think this is something that only we could have done. It's something that lots of schools could do," he said. "It would be lovely to have this sense of community around learning all over the country and all over the world."
Images: 1) A buff-tailed bumblebee (Bombus terrestris). Wikimedia Commons/Alvesgaspar. 2) Courtesy of Beau Lotto. 3) P.S. Blackawton et al/Current Biology 4) Courtesy of Beau Lotto.
Posted: 21 Dec 2010 04:01 PM PST
Borrowing biological designs from the black ghost knifefish, engineers have built a swimming robot that reveals how the animal's trick of vertical movement works.
Called GhostBot, the robot copies the real fish's undulating, ribbon-like ventral fin to propel itself through the water. New high-speed experiments show how, when waves travel along the robot's ribbon from head to tail and meet in the middle, mushroom-cloud-like jets can push it upward.
"These fish are extremely maneuverable, and we knew how they move forward and backward with their fins," said bioengineer Malcolm MacIver of Northwestern University, who helped design GhostBot. "What we didn't know was how they move vertically."
The black ghost knifefish lives in the floodplains of the Amazon River, using a self-generating electric field to see through the murky waters. It doesn't have traditional fins like a bony fish, nor does it sway its body like an eel to move around. Instead, it stays rigid and uses a ribbon-like fin along its belly to navigate through a maze of downed trees, stones and other underwater obstructions with extreme precision.
Emulating such maneuverability in robotic submersibles would create countless opportunities for new or more robust underwater research, says MacIver, co-author of a study detailing the vertical movement mechanics in an upcoming issue of the Journal of the Royal Society Interface. An efficient, submersible hovering robot, for example, could constantly take inventory of a coral reef without crashing into it (most researchers hire costly divers to do the work).
"I don't agree that nature always has the best designs, but this is a place where it's way ahead of human technology," MacIver said.
When a knifefish moves upward in water, it rolls two opposing waves down its fin that meet in the middle. How that action generates upward thrust — which the dense fish needs, otherwise it'd sink — was a puzzle until the research team, including Brown university mechanical engineer Oscar Curet, decided to build a copycat robot.
"Animals usually never behave the way you need them to do while studying their movements," Curet said. "With robotics that mimic animal movement, you do something over and over again without hurting the animal."
To reveal how the black ghost and other knifefish move vertically, the scientists worked with a company called Kinea Design to build GhostBot. It took them about 7 months and $200,000 to complete a finished version.
They put the forearm-sized device into a special tank able to reveal the fluid mechanics near the fin. It flowed water laced with shiny particles over the swimming robot, shined a laser-beam plane onto the ribbon fin and took footage with high-speed cameras. Computer algorithms then processed the images to map particle velocities.
"While swimming upward, two opposing jest of water meet in the middle and collide. The merged jets deflect downward and push up on the fish," Curet said. The animal can modulate the jets to move in diagonal directions as well, he says.
"This kind of ribbon fin is something worth paying attention to, because it has independently evolved around the world many times," said Noah Cowan, a biologist and mechanical engineer at Johns Hopkins University who wasn't involved in the study. "It's a very robust design by nature, and these particular animals can move with very little body bending. It may be good for moving a rigid submersible robot."
A major robotics company interested in developing autonomous submersibles is already discussing how they can use the design, MacIver says. Attaching ribbon-like mechanical fins to submarines people fit into, however, is another matter.
"It sounds fantastic for autonomous submersibles, but we may never use it. The design seems too fragile to sit on the ocean floor, which is what customers sometimes do with our submarines," said Patrick Lahey, a mechanical engineer and president of manufacturing at Triton Sumarines. "For safety reasons, we have to adhere to tried and tested technologies."
In addition to GhostBot's unusual means of swimming, MacIver says it's also packed with sensors emulating the real animal's electrosensing abilities.
"They basically use their body as a big eye," he said. "We want to connect the robot's swimming to its sensor network and show it can autonomously find an object we want, then hover to say, 'here it is.'"
Videos: 1) High-speed footage of a swimming black ghost knifefish, the submersible GhostBot, and fluid mechanics experiments performed on the device. Credit: Journal of the Royal Society Interface. 2) A black ghost knifefish swims in strange directions to find and eat food. Credit: YouTube.
Image: Fluid mechanics models showing how the black ghost knifefish's vertical jets form and push upward on its body. Credit: Journal of the Royal Society Interface.
Posted: 21 Dec 2010 11:46 AM PST
An experimental simulation of near-future changes in ocean chemistry suggests that aquatic nitrogen cycles could be profoundly disrupted, altering the basic structure of Earth's food webs.
Nitrogen is one of life's crucial elements, used by all organisms to make proteins. Bacterial communities are responsible for cycling nitrogen in the ocean, and they appear sensitive to water acidifying from the absorption of carbon dioxide.
"Microbial nitrification rates decreased in every instance when pH was experimentally reduced at multiple locations in the Atlantic and Pacific oceans," wrote researchers led by University of California, Merced, biogeochemist J. Michael Beman in the Dec. 21 Proceedings of the National Academy of Sciences. "Our results suggest that ocean acidification could reduce nitrification rates by 3 to 44 percent within the next few decades … fundamentally altering nitrogen cycling in the sea."
The findings are the latest in a line of research that's added a new and troubling implication to ocean acidification, a phenomenon already plenty troubling.
Oceans are Earth's great CO2 sink, having absorbed one-third of human CO2 emissions over the past two centuries. As a result, the concentration of hydrogen ions has increased, making waters more acidic. Earth's oceanic pH has dropped by 0.1 in the last century, and is expected to drop by another 0.1 over the next several decades. For those who remember litmus tests in high school chemistry, Earth is losing blue.
Corals, mollusks, crustaceans and other creatures with shells made of calcium carbonate are clearly threatened by acidifying waters, which literally corrode their shells. Of the disproportionately scant public attention paid to ocean acidification, dissolving shellfish get the most. But a few researchers have started studying what acidification means for ocean microbes — a kingdom of life that makes up most aquatic biomass, is a major driver of Earth's biogeochemical cycles, and is just starting to be understood.
One key microbial task is nitrification, turning ammonium into nitrite and then into useful-to-organisms nitrates. In a series of laboratory flask experiments, limited ocean trials and long-term lake trials, researchers have demonstrated that increased acidity seems to reduce microbial nitrification rates. Beman and colleagues conducted the most comprehensive ocean trial to date, taking water samples from waters near Hawaii, Los Angeles, Bermuda and in the Sargasso Sea, then adding CO2 and measuring how nitrification changed.
As the waters' pH decreased from 8.1 to 8.0, or what's expected in the next 20 to 30 years, ammonium-to-nitrite conversion dropped by an average of 21 percent. "Such a change would have major implications for the global marine-nitrogen cycle," wrote the researchers, noting that nitrification in sunlit waters is responsible for one-third of all organic compounds produced in the ocean.
In addition to altering the total amounts of available nitrates, their composition would also change, favoring some organisms while threatening others. Especially threatened would be diatoms, one of the most common types of algae, which are specialized to metabolize certain types of nitrates.
Specific predictions about what this means were beyond the study's scope, but it would likely have "potentially important implications for oceanic food webs, fisheries and carbon export to the deep sea," wrote the researchers. "As anthropogenic CO2 invades the ocean, pH-driven reductions in ammonia oxidation rates could fundamentally change how nitrogen is cycled and used by organisms in the sea."
Image: A plankton bloom in the Barents Sea. Shades of green come from diatoms./NASA.
Citation: "Global declines in oceanic nitrification rates as a consequence of ocean acidification." By J. Michael Beman, Cheryl-Emiliane Chow, Andrew L. King, Yuanyuan Feng, Jed A. Fuhrman, Andreas Andersson, Nicholas R. Bates, Brian N. Popp, David A. Hutchins. Proceedings of the National Academy of Sciences, Vol. 107 No. 51, Dec. 21, 2010.
Posted: 21 Dec 2010 10:12 AM PST
Last night, the Earth passed between the sun and the moon, turning the moon a deep blood red and sending astronomy buffs to their cameras. As a bonus, this lunar eclipse was the first to fall on the winter solstice since 1638. The next solstice eclipse won't be until 2094.
But if you missed it, there's still plenty to look forward to. Starting in April 2014, there will be four total lunar eclipses visible from all of North America in less than two years.
Here's a sampling of the best shots of our rusty celestial sidekick from Wired Science readers all over the continent. Keep them coming, and we'll update the gallery as we get more good contributions.
Posted: 21 Dec 2010 09:25 AM PST
Using the genetic equivalent of the Hubble telescope, researchers have peered into the distant past and witnessed an explosion of new genes that happened more than 3 billion years ago.
About 27 percent of all gene families that exist today were born between 3.3 billion and 2.8 billion years ago, two researchers from MIT reported online Dec. 19 in Nature. The surge of gene births — which the scientists have dubbed the Archean expansion — predate some important changes in Earth's early chemistry, including the appearance of large amounts of oxygen in the atmosphere, say evolutionary biologists Eric Alm and Lawrence David.
The study may show how early organisms responded to and helped alter the planet's chemistry. Daniel Segrè, a computational biologist at Boston University, says that the work provides "insight into really ancient metabolic events."
Fossils of organisms billions of years old are difficult to find. The earliest organisms might not have been preserved in stone at all. Most familiar fossils appeared in the Cambrian period more than 540 million years ago. Some stromatolites — fossils of cyanobacteria — are as much as 3.4 billion years old.
But the researchers have found a rich molecular fossil bed billions of years old in the genetic blueprints of living organisms.
"Imprinted in the DNA of modern organisms is the history of these Precambrian events," says Alm.
To read that history, the researchers traced the evolution of 3,983 gene families in the genomes of 100 different living species. Gene families are groups of genes that share similar structures and functions.
Analyzing that amount of data is a technical tour de force, says Jason Raymond of Arizona State University in Tempe. Most researchers painstakingly reconstruct the evolutionary history of one gene at a time, he says. By simultaneously examining how thousands of genes changed over time to produce the variation seen in organisms today, "they've leapfrogged other researchers," he says. "If they'd have done this 10 years ago, I'd be out of a Ph.D."
Genes for shuttling electrons burst onto the scene about 3.3 billion years ago, the researchers calculate. Those genes, known as electron-transport genes, are important for such processes as photosynthesis and respiration. By increasing the energy efficiency of some early life forms, these genes may have enabled populations to thrive.
Genes for using oxygen appeared at the tail of the genetic expansion around 2.8 billion years ago, long before oxygen began accumulating in the atmosphere around 2.5 billion years ago. The team also found evidence for the birth of genes for processing nitrogen and for using iron, molybdenum, copper and other elements.
While the genetic predictions match geochemical data for many of the elements, a few appear to contradict ideas about Earth's early history. For instance, the new data predict that genes for using nickel were increasing at a time when geochemists say nickel concentrations in the ocean were crashing.
"Somebody's wrong, and that's what's really exciting to me," says Timothy Lyons, a geochemist at the University of California, Riverside. While he doesn't expect the genetic models to single-handedly overturn geochemical models of the early ocean, the new study might help refine chemical predictions. The genetic data is "another control and constraint that can't be ignored."
Image: Flickr/A Hermida
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