"STUDY ON MAGNETIC COMPASS ORIENTATION IN BIRDS BUILDS CASE FOR BIO-INSPIRED SENSORS",
2014-05-09 press release from DARPA [web.archive.org/web/20140523030409/http://www.darpa.mil/NewsEvents/Releases/2014/05/09.aspx]:
Researchers show that migratory birds are unable to use their magnetic compass in the presence of urban electromagnetic noise. The findings open up new areas of study for magnetic sensors.
Researchers working on DARPA’s Quantum Effects in Biological Environments (QuBE) program have shown that the electromagnetic noise that permeates modern urban environments can disrupt a bird’s internal magnetic compass. The findings settle a decades-long debate into whether low-level, artificial electric and magnetic fields can affect biological processes in higher vertebrates. For DARPA, the results hint at a new class of bio-inspired sensors at the intersection of biology and quantum physics.
In an online Nature paper [http://www.nature.com/nature/journal/v509/n7500/full/nature13290.html], research teams from the University of Oldenburg and the University of Oxford, led by Prof. Henrik Mouritsen, document a series of experiments using European robins that were carried out from 2005 to 2011.
Night-migratory songbirds like European robins have an internal magnetic compass that allows them to choose the correct migratory direction during the spring and fall migration seasons. However, when the robins used in the Oldenburg experiments were exposed to everyday levels of electromagnetic background noise, the birds failed to orient themselves correctly. When the researchers later shielded the birds from background electromagnetic noise, the birds oriented to the correct migratory direction. Birds tested in rural environments, far from sources of electromagnetic noise, required no screening to properly orient using their magnetic compass. Full details of the experiments are available in the paper.
Electromagnetic noise is emitted everywhere that humans use electronic devices. The observations from the Oldenburg study suggest that birds utilize a biological system that is sensitive to manmade electromagnetic noise with intensities well below the guidelines for human exposure adopted by the World Health Organization.
But why is DARPA studying bird migration? According to Dr. Matt Goodman, the Program Manager for QuBE, one reason is that the observed phenomena might have their roots in quantum physics.
“Nature is an extraordinary testbed. We think it’s possible that over millions of years of evolution, biological organisms have developed systems that exploit quantum physics,” Goodman said. “The QuBE program is designed to test this hypothesis. The work we’re pursuing questions fundamental assumptions about how biological processes work.”
If manifestly quantum effects are shown to be at play in biological systems, and scientists can understand the mechanisms at work, the findings could lead to fundamentally new technologies, including bio-inspired sensors. In addition to exploring magnetic navigation, QuBE researchers are also studying photosynthesis, olfaction, and the underlying theoretical framework needed to link biology and quantum phenomena.
“The time and cost to develop many of the traditional sensors that the Department of Defense uses is substantial. Nature, on the other hand, has already evolved extraordinary capabilities—think of a dog’s sense of smell,” Goodman explained. “In addition to being extremely capable, natural sensors are also robust, durable, exhibit great sensitivity and enormous selectivity, and are produced amid the dirt and dust of the natural world; nature doesn’t need clean rooms. We’re hoping to follow nature’s lead to capture those qualities in manmade sensor systems.”
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QUANTUM EFFECTS IN BIOLOGICAL ENVIRONMENTS (QUBE) -
PROGRAM MANAGER: Dr. Matthew Goodman [matthew.goodman (@darpa.mil]
[https://web.archive.org/web/20131017060104/http://www.darpa.mil/Our_Work/DSO/Programs/Quantum_Effects_in_Biological_Environments_(QUBE).aspx]:
Biological sensors often display high sensitivity, selectivity, and low false alarm rates while being fabricated and operated in dirty, noisy natural environments. Attempts to emulate these sensors synthetically have not fully met expectations. Recent evidence suggests that some biological sensors exploit nontrivial quantum mechanical effects to produce macroscopic output signals. Examples of such sensors include the highly efficient energy transfer properties of photosynthesis in plants, bacteria, and algae; magnetic field sensing used by some birds for navigation; and the ability of some animals to detect odors at the single molecule level. The Quantum Effects in Biological Environments (QuBE) program is laying the foundation for novel sensor designs by challenging the long-held view that biological sensors utilize primarily classical physics. QuBE will verify, understand, and exploit these effects to develop new scientific foundations for sensor technologies for military applications.
Anthropogenic electromagnetic noise disrupts magnetic compass orientation in a migratory bird"
2014-01-28 from Svenja Engels, Nils-Lasse Schneider, Nele Lefeldt, Christine Maira Hein, Manuela Zapka, Andreas Michalik, Dana Elbers, Achim Kittel, P. J. Hore & Henrik Mouritsen [www.nature.com/nature/journal/v509/n7500/full/nature13290.html]:
SYNOPSIS -
Electromagnetic noise is emitted everywhere humans use electronic devices. For decades, it has been hotly debated whether man-made electric and magnetic fields affect biological processes, including human health (footnotes 1, 2, 3, 4, 5). So far, no putative effect of anthropogenic electromagnetic noise at intensities below the guidelines adopted by the World Health Organization1, 2 has withstood the test of independent replication under truly blinded experimental conditions. No effect has therefore been widely accepted as scientifically proven (footnotes 1, 2, 3, 4, 5, 6). Here we show that migratory birds are unable to use their magnetic compass in the presence of urban electromagnetic noise. When European robins, Erithacus rubecula, were exposed to the background electromagnetic noise present in unscreened wooden huts at the University of Oldenburg campus, they could not orient using their magnetic compass. Their magnetic orientation capabilities reappeared in electrically grounded, aluminum-screened huts, which attenuated electromagnetic noise in the frequency range from 50 kHz to 5 MHz by approximately two orders of magnitude. When the grounding was removed or when broadband electromagnetic noise was deliberately generated inside the screened and grounded huts, the birds again lost their magnetic orientation capabilities. The disruptive effect of radiofrequency electromagnetic fields is not confined to a narrow frequency band and birds tested far from sources of electromagnetic noise required no screening to orient with their magnetic compass. These fully double-blinded tests document a reproducible effect of anthropogenic electromagnetic noise on the behaviour of an intact vertebrate.
footnotes:
* 1. International Commission for Non-Ionizing Radiation Protection. ICNIRP guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (up to 300 GHz). Health Phys. 74, 494–522 (1998)
* 2. International Commission for Non-Ionizing Radiation Protection. ICNIRP statement on the “Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (up to 300 GHz)”. Health Phys. 97, 257–258 (2009)
* 3. World Health Organization. Extremely Low Frequency Fields. Environmental Health Criteria Monograph no. 238,. http://www.who.int/peh-emf/publications/elf_ehc/en/ (2007)
* 4. Health Protection Agency. Health Effects from Radiofrequency Electromagnetic Fields. http://www.hpa.org.uk/webc/HPAwebFile/HPAweb_C/1317133827077 (2012)
* 5. The INTERPHONE Study Group Brain tumour risk in relation to mobile telephone use: results of the INTERPHONE international case–control study. Int. J. Epidemiol. 39, 675–694 (2010)
* 6. Johansen, C. et al. Cellular telephones and cancer—a nationwide cohort study in Denmark. J. Natl. Cancer Inst. 93, 203–207 (2001)
"Dolphins are attracted to magnets;
Add dolphins to the list of magnetosensitive animals, French researchers say" (2014-09-29) [Springer.com link] [archive.org]:
Dolphins are indeed sensitive to magnetic stimuli, as they behave differently when swimming near magnetized objects. So says Dorothee Kremers and her colleagues at Ethos unit of the Université de Rennes in France, in a study in Springer’s journal Naturwissenschaften – The Science of Nature. Their research, conducted in the delphinarium of Planète Sauvage in France, provides experimental behavioral proof that these marine animals are magnetoreceptive.
Magnetoreception implies the ability to perceive a magnetic field. It is supposed to play an important role in how some land and aquatic species orientate and navigate themselves. Some observations of the migration routes of free-ranging cetaceans, such as whales, dolphins and porpoises, and their stranding sites suggested that they may also be sensitive to geomagnetic fields.
Because experimental evidence in this regard has been lacking, Kremers and her colleagues set out to study the behavior of six bottlenose dolphins in the delphinarium of Planète Sauvage in Port-Saint-Père. This outdoor facility consists of four pools, covering 2,000 m² of water surface. They watched the animals’ spontaneous reaction to a barrel containing a strongly magnetized block or a demagnetized one. Except from this characteristic, the blocks were identical in form and density. The barrels were therefore indistinguishable as far as echolocation was concerned, the method by which dolphins locate objects by bouncing sound waves off them.
During the experimental sessions, the animals were free to swim in and out of the pool where the barrel was installed. All six dolphins were studied simultaneously, while all group members were free to interact at any time with the barrel during a given session. The person who was assigned the job to place the barrels in the pools did not know whether it was magnetized or not. This was also true for the person who analyzed the videos showing how the various dolphins reacted to the barrels.
The analyses of Ethos team revealed that the dolphins approached the barrel much faster when it contained a strongly magnetized block than when it contained a similar not magnetized one. However, the dolphins did not interact with both types of barrels differently. They may therefore have been more intrigued than physically drawn to the barrel with the magnetized block.
“Dolphins are able to discriminate between objects based on their magnetic properties, which is a prerequisite for magnetoreception-based navigation,” says Kremers. “Our results provide new, experimentally obtained evidence that cetaceans have a magenetic sense, and should therefore be added to the list of magnetosensitive species.”
Reference: Kremers, D. et al. (2014). Behavioural evidence of magnetoreception in dolphin: Detection of experimental magnetic fields. Naturwissenschaften – The Science of Nature. DOI 10.1007/s00114-014-1231-x
"Study confirms link between salmon migration and magnetic field"
2014-02-06 from Oregon State University [https://web.archive.org/web/20140209071127/http://oregonstate.edu/ua/ncs/archives/2014/feb/study-confirms-link-between-salmon-migration-and-magnetic-field]:
CORVALLIS, Ore. – A team of scientists last year presented evidence of a correlation between the migration patterns of ocean salmon and the Earth’s magnetic field, suggesting it may help explain how the fish can navigate across thousands of miles of water to find their river of origin.
This week, scientists confirmed the connection between salmon and the magnetic field following a series of experiments at the Oregon Hatchery Research Center in the Alsea River basin. Researchers exposed hundreds of juvenile Chinook salmon to different magnetic fields that exist at the latitudinal extremes of their oceanic range. Fish responded to these “simulated magnetic displacements” by swimming in the direction that would bring that toward the center of their marine feeding grounds.
The study, which was funded by Oregon Sea Grant and the Oregon Department of Fish and Wildlife, will be published this month in the forthcoming issue of Current Biology.
“What is particularly exciting about these experiments is that the fish we tested had never left the hatchery and thus we know that their responses were not learned or based on experience, but rather they were inherited,” said Nathan Putman, a postdoctoral researcher in Oregon State University’s Department of Fisheries and Wildlife and lead author on the study.
“These fish are programmed to know what to do before they ever reach the ocean,” he added.
To test the hypothesis, the researchers constructed a large platform with copper wires running horizontally and vertically around the perimeter. By running electrical current through the wires, the scientists could create a magnetic field and control both the intensity and inclination angle of the field. They then placed 2-inch juvenile salmon called “parr” in 5-gallon buckets and, after an acclimation period, monitored and photographed the direction in which they were swimming.
Fish presented with a magnetic field characteristic of the northern limits of the oceanic range of Chinook salmon were more likely to swim in a southerly direction, while fish encountering a far southern field tended to swim north. In essence, fish possess a “map sense” determining where they are and which way to swim based on the magnetic fields they encounter.
“The evidence is irrefutable,” said co-author David Noakes of OSU, senior scientist at the Oregon Hatchery Research Center and the 2012 recipient of the American Fisheries Society’s Award of Excellence. “I tell people: The fish can detect and respond to the Earth’s magnetic field. There can be no doubt of that.”
Not all of the more than 1,000 fish swam in the same direction, Putman said. But there was a clear preference by the fish for swimming in the direction away from the magnetic field that was “wrong” for them. Fish that remained in the magnetic field of the testing site – near Alsea, Ore. – were randomly oriented, indicating that orientation of fish subjected to magnetic displacements could only be attributable to change in the magnetic field.
“What is really surprising is that these fish were only exposed to the magnetic field we created for about eight minutes,” Putman pointed out. “And the field was not even strong enough to deflect a compass needle.”
Putman said that salmon must be particularly sensitive because the Earth’s magnetic field is relatively weak. Because of that, it may not take much to interfere with their navigational abilities. Many structures contain electrical wires or reinforcing iron that could potentially affect the orientation of fish early in their life cycle, the researchers say.
“Fish are raised in hatcheries where there are electrical and magnetic influences,” Noakes said, “and some will encounter electrical fields while passing through power dams. When they reach the ocean, they may swim by structures or cables that could interfere with navigation. Do these have an impact? We don’t yet know.”
Putman said natural disruptions could include chunks of iron in the Earth’s crust, though “salmon have been dealing with that for thousands of years.”
“Juvenile salmon face their highest mortality during the period when the first enter the ocean,” Putman said, “because they have to adapt to a saltwater environment, find food, avoid predation, and begin their journey. Anything that makes them navigate less efficiently is a concern because if they take a wrong turn and end up in a barren part of the ocean, they are going to starve.”
The magnetic field is likely not the only tool salmon use to navigate, however, Putman noted.
“They likely have a whole suite of navigational aids that help them get where they are going, perhaps including orientation to the sun, sense of smell and others,” Putman said.
The Oregon Hatchery Research Center is funded by the Oregon Department of Fish and Wildlife and jointly run by ODFW and Oregon State University.
"Experiment proves salmon use Earth's magnetic field to navigate"
2014-02-06 from "United Press International (UPI)" newswire
[https://web.archive.org/web/20140211191435/http://www.upi.com/Science_News/2014/02/06/Experiment-proves-salmon-use-Earths-magnetic-field-to-navigate/UPI-10581391723911/]:
CORVALLIS, Ore., Feb. 6 (UPI) -- U.S. scientists say they've confirmed salmon are using Earth's magnetic field to navigate across thousands of miles of water to find their rivers of origin.
Researchers at Oregon State University report exposing hundreds of juvenile Chinook salmon at the Oregon Hatchery Research Center to different magnetic fields that exist at the latitudinal extremes of their oceanic range.
Fish responded to the "simulated magnetic displacements" by swimming in the direction that would bring them toward the center of their marine feeding grounds, the university reported Thursday.
"What is particularly exciting about these experiments is that the fish we tested had never left the hatchery and thus we know that their responses were not learned or based on experience, but rather they were inherited," study lead author Nathan Putman said.
In the experiment, fish presented with an artificial magnetic field characteristic of the northern limits of the oceanic range of Chinook salmon were more likely to swim in a southerly direction, while fish encountering a far southern field tended to swim north, the researchers said.
The finding proves fish possess a "map sense" determining where they are and which way to swim based on the magnetic fields they encounter, they said.
"These fish are programmed to know what to do before they ever reach the ocean," Putnam, a postdoctoral researcher, said.
A new study using small Chinook salmon found the fish use the Earth's magnetic field to orient themselves. Credit: Oregon State University
