Trees Have Internal Clocks Too, Study Finds

Tasmanian blue gum trees follow daily cycles
of water and carbon dioxide intake.
Credit: metriognome | Shutterstock

Trees Have Internal Clocks Too, Study Finds
July 18, 2013 | Live Science | Tanya Lewis

Like human bodies, some trees have internal clocks that coordinate the activities of their cells with the cycles of day and night, a new study finds.

Scientists knew of these circadian rhythms in leaves, but the new study is the first to demonstrate them in whole trees. In the study, the researchers looked at the Tasmanian blue gum tree, and found it appears to use its internal clock to regulate its intake of water and carbon dioxide. These cycles could affect models of climate change, the scientists say.

"It had never been shown that the circadian rhythm of the leaf affected the whole tree," said study researcher Rubén Díaz Sierra, a physicist at the National University of Distance Education in Spain. "If it works for the tree, it works for the whole forest," he added.

Díaz Sierra's colleagues monitored trees in special "whole-tree chambers" as part of the Hawkesbury Forest Experiment near Sydney, Australia — a broader experiment to study how Australia's eucalypt forests will respond to changes in atmospheric carbon dioxide and climate. These chambers enable researchers to control the air temperature, humidity and amount of light the trees are exposed to, although these parameters were allowed to vary in this study. [Nature's Giants: Tallest Trees on Earth]

The researchers measured how much carbon dioxide the trees took in and how much water vapor they lost through small openings in the their leaves called stomata. The scientists then compared these values during overcast nights, when the environment stays mostly constant throughout the evening, with nights that saw dramatic changes in temperature and humidity.

Both carbon-dioxide intake and water loss declined in the six hours after dusk, but increased noticeably during the six hours before dawn, even on nights when temperature and humidity remained constant. Because the environment wasn't changing, the increase can only be explained by the biological clock, said study researcher Víctor Resco de Dios of the University of Western Sydney in Australia.

Artificial neural networks — machine-learning models inspired by the brain — were used to determine just how much the circadian rhythms affected the opening of stomata and the trees' water use.

The findings carry important implications for models of climate change. "Right now, the models don't take into account the time of the day," Díaz Sierra said, adding that if the time of day affects trees' carbon-dioxide consumption, it would alter models of how climate change will affect ecosystems.

Still, Díaz Sierra expects some resistance to the notion that whole trees display circadian rhythms. There's still a lot of work to do with other plants, he said. "But if it works on small plants on the leaves, why not the whole tree?" he said.

Follow Tanya Lewis on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on LiveScience.com.

Dolphins May 'See' Pregnant Women's Fetuses

Dolphins may use ultrasound to detect
a baby inside a pregnant woman.
CREDIT: Brian Branstetter

Dolphins May 'See' Pregnant Women's Fetuses
July 10, 2013 | Live Science | Tanya Lewis

Using echolocation, dolphins might be able to detect a pregnant woman's developing fetus, some experts say.

Dolphins emit sounds in their environment and listen to the echoes that return — a process that helps them identify the shapes and locations of objects. Doctors use a similar technique to image a developing human baby. Both involve ultrasound — high-pitched pulses of sound above the range of human hearing.

"I think it's extremely plausible [dolphins] would be able to detect a fetus," said Lori Marino, a neuroscientist at Emory University in Atlanta who studies cetacean intelligence. However, "you'd have to really do a well-controlled study to make a definitive statement," she cautioned.

Fetal buzz-ogram

Anecdotal reports suggest dolphins take a special interest in pregnant women. The animals supposedly swim up to the expecting women and make buzzing sounds near the women's tummies. "Buzzing" is a form of very concentrated echolocation. When the dolphins want to hone in on something or stimulate another dolphin, they put their snout against the skin and buzz, Marino said, adding, "It sounds like a squeaky door." [The 10 Strangest Pregnancies in the Animal Kingdom]

Malcolm Nicolson, a history of medicine professor at the University of Glasgow in Scotland, agreed that dolphins may be able to detect a human woman's pregnancy. For instance, a dolphin that swims with a female trainer before and after she becomes pregnant "might well be able to detect a difference in her echo profile," or the pattern of sounds returned by echolocation, Nicolson said. Dolphins might even have the ability to detect a fetal heartbeat in a woman they have never bumped up against before, he added. But Nicolson, who wrote a book on the development of obstetric ultrasound, noted that this was only speculation.

At least one study has found that dolphins can perceive shapes through an opaque barrier, such as a box. "It would seem logical that they would have the potential to discriminate between different humans" who are pregnant or not, said Mike Walsh, an aquatic animal veterinarian at the University of Florida. After all, water is the perfect medium for ultrasound, Walsh said. Still, the dolphins may not know that what they're seeing inside the pregnant woman is a person, he said.

Marino said she thinks dolphins probably see some sort of image of the baby. "We know from other studies that they are very good at going from a visual image to an acoustic image," and vice versa, Marino said. Just as sonograms give people a visual image of their babies, echolocation might give dolphins a mental image of them.

By extension, it's quite possible that dolphins can detect pregnancies in other dolphins, Marino said. Indeed, the animals have been seen buzzing on other pregnant dolphins. Dolphins use echolocation for many different purposes, from communicating in a group to disciplining their offspring, Marino said, adding, "They're always buzzing!"

Dolphin abilities

Dolphins probably aren't born with their echolocation ability, but develop it over time. Baby dolphins, for instance, babble before they learn to make more complex sounds, Marino said. She suspects their echolocation must be learned as well.

Even though dolphins might be able to detect a pregnancy, giving birth near dolphins may be a bad idea, as the meat-eating marine mammals are known to sometimes be aggressive, scientists say.

Some people claim dolphins also have the ability to diagnose or treat human ailments, but these claims are much less credible, Marino said. For example, people have reported dolphins acting strangely in the presence of someone with a cancerous tumor. However, there's no evidence to substantiate this claim, Marino said, and no evidence that dolphins can heal people using echolocation.

Follow Tanya Lewis on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on LiveScience.com.

Dark and Dirty: The Cutthroat Side of Science

Scientists aren't perfect: For all the
Dr. Jekylls, there are a few Mr. Hydes.
CREDIT: Chicago : National Prtg. & Engr. Co.

Dark and Dirty: The Cutthroat Side of Science
May 4, 2013 | Live Science | Tanya Lewis

NEW YORK — Being a scientist is a noble profession, but it has its darker side. From fierce competition to plagiarism to outright scientific fraud, scientists are far from immune to the sordid.

A panel of experts discussed the slimy side of science at an event held here on April 30 at the New York Academy of Sciences and moderated by "Scientific American" Editor-in-Chief Mariette DiChristina.

Dr. Morton Meyers, professor and emeritus chairman of the department of radiology at the State University of New York (SUNY) at Stony Brook, recounted historical conflicts over the Nobel Prize; Harold "Skip" Garner, a professor at Virginia Bioinformatics Institute at Virginia Tech, described wholesale plagiarism in scientific literature; and Dr. Ivan Oransky, executive editor of Reuters Health, delved into the slippery world of retracted studies.

Scientists "are people who have ambition and envy and jealousy, just as you and I do," Meyers said at the event. It's "interesting to lift the veil on scientific discovery to trace the human elements that underlie many of these things." [7 Personality Traits You Should Change]

Battle for recognition

As most humans do, scientists seek recognition for their efforts, and nowhere are the stakes higher than for that pinnacle of scientific honor: the Nobel Prize. Meyers' new book, "Prize Fight: The Race and the Rivalry to be the First in Science" (Palgrave Macmillan, 2012) deals with some of the great conflicts over priority and credit in the Nobels.

One such conflict involved the inventor and biochemist Selman Waksman and his then-graduate student Albert Schatz. Waksman and Schatz were studying antibiotics found in the soil when they came across streptomycin, the first antibiotic effective against tuberculosis. The two patented and published their research. Schatz was listed as first author on the paper but second on the patent.

Waksman was awarded a Nobel Prize for the discovery of streptomycin in 1952, prompting Schatz to sue Waksman for a share of the credit and the patent royalties. Schatz won a settlement, but was blacklisted from getting a job and faced major struggles for the rest of his career. [Top 10 Mad Scientists]

"Both were right, and both were wrong," Meyers said. The story illustrates the gray area of apportioning credit in a supervisor-graduate-student collaboration. But in other cases, it is more black and white who deserves the credit.

'Borrowed' work

Scientists are usually fastidious about citing their work, but sometimes the pressures to publish become too great. With success in academia tied to scientific output, it's not surprising that some researchers stray into plagiarism.

Garner found such plagiarism while developing software to search the Web for paragraphs of text in order to track down scientific studies. In doing so, he inadvertently stumbled upon a plethora of results that "were virtually identical but had author sets that were nonoverlapping," Garner said. In other words, the papers were "borrowed" and republished by other scientists without the correct attribution.

Garner ran his program on a supercomputer, comparing the texts of tens of millions of scientific articles. From the results, he created the "Déjà Vu Database," containing about 80,000 pairs of papers that were more similar than mere chance would allow. About 10 percent of these appeared to have two sets of authors, so Garner sent questionnaires to the authors, asking them to explain the duplication.

"Ninety-five percent of the original authors were unaware of being ripped off," Garner said. About one-third of the copiers said they didn't think the practice was wrong, another third apologized and the rest made excuses, such as not knowing they were an author.

Some pretty prominent people were among the copiers, including the chairman of the clinical department of a prominent university in Boston, and a former vice president of Iran, Garner said. He even received mortal threats from the Iranian VP.

Garner has developed similar technology to detect instances of fraud, such as applying for multiple grants for one study. In biomedicine, such "double-dipping" accounts for $200 million to $300 million in government spending, Garner estimated. Ultimately, Garner hopes the government will make use of this software to prevent this kind of malfeasance.

Retract that

But it doesn't always stop with copying. In some cases, individuals stray into the realm of fabrication.
The number of scientific retractions — statements that a scientific study should not have been published because its data or conclusions are erroneous, plagiarized or made up —  has been growing steadily in recent years, at a rate that outstrips the increase in studies.

Oransky and Adam Marcus, managing editor of "Anethesiology News," run a blog called Retraction Watch. They started the blog because they wanted to shine a light on retractions. Some retractions are the result of minor mistakes, but all too frequently, foul play is involved.

Some scientists are repeat offenders. Take the Dutch psychologist Diederik Stapel, who has been in the news recently for committing academic fraud in several dozen published papers.

Then there's the Japanese scientist Yoshitaka Fujii, who has had 183 papers retracted, Oransky said. Or the South Korean plant scientist Hyung-In Moon, who faked other scientists' email addresses so he could review his own papers.

It was once thought that misconduct was behind fewer than half of retractions, but it turns out to be responsible for two-thirds of them, Oransky said. The problem is compounded by the fact that retracted papers remain in scientific-article databases, so people continue to read and cite them.

In light of all these problems, science loses some of its luster. But as in any profession, it's important to remember that "scientists are humans, too," Garner said.

Follow Tanya Lewis on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on LiveScience.com.