Health & Science

Why dolphins died off in the Gulf

When record numbers of dead bottlenose dolphins washed ashore last year in the Gulf of Mexico, some researchers were quick to blame the 2010 BP oil spill. Now a new study suggests that the spill was just part of “a perfect storm” of events causing the unusual die-off, University of Central Florida biologist Graham Worthy tells LiveScience.com. In the first four months of 2011, 186 dolphins washed ashore in the northern Gulf, nearly half of them newborns. Most of the creatures were underweight and had thin blubber layers, suggesting that oil from the spill had left them short of healthy prey. The dead dolphins were also found to have low levels of a hormone that helps the body cope with stress and is often depleted in mammals exposed to oil. But the spill wasn’t the only difficulty these dolphins had faced: Before the well started spewing oil, in April 2010, Gulf dolphins had endured a particularly cold winter that lowered their defenses. “The final blow” came in early 2011, Worthy says, when the Mississippi River delivered unusually large amounts of very cold freshwater to Mobile Bay. That influx “assaulted” the dolphins’ fragile health, says study co-author Ruth H. Carmichael, “essentially kicking them when they were already down.”

Awe to nourish the soul

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Gazing at a beautiful landscape or listening to a majestic symphony may make people feel less rushed, more patient, and more compassionate toward others. Stanford University researchers have discovered that awe—as opposed to joy or other positive emotions—gives people the sense that time has slowed down. That feeling, in turn, has a major impact on “everyday decision making,” study author Melanie Rudd tells LiveScience.com. She and her colleagues showed one group of volunteers a video of awe-inspiring scenes, such as waterfalls and breaching whales, and another group a happy video featuring confetti and a parade. The researchers also had participants read or write about either an awesome experience or a blander one. When they quizzed the volunteers afterward, those who had watched, read about, or recalled an awesome moment were more likely to report feeling unhurried. They were also more apt to agree to donate their time to charity, and to prefer spending money on experiences, such as seeing a play, rather than on material goods. Researchers say the participants reported that the “small dose of awe” had given them “a momentary boost in life satisfaction.”

Screen-viewing blues

Spending evenings in front of a glowing computer, TV, or cellphone screen can put you at risk of depression, Science News reports. Nighttime exposure to light from gadgets has already been shown to contribute to insomnia, cancer, obesity, and diabetes. Now, a new study shows that screen glow can cause mood-related changes in the brain. For weeks, researchers exposed hamsters to eight hours a night of dim light—like that from a TV screen—instead of their usual eight hours of pitch darkness. They found that the rodents became lethargic and ignored their favorite sugary treats, suggesting that they weren’t deriving “pleasure out of activities they once enjoyed”—a major indication of depression in humans, says study author Tracy Bedrosian. The rodents’ brains also showed the same kinds of changes in the hippocampus that are common in depressed people. “The good news,” Bedrosian says, is that the damage disappeared and the rodents’ behavior returned to normal after researchers took the night lights away, meaning that simply powering down earlier may “undo some of the harmful effects” that late-night gadget users face. Over the past 50 years, depression rates in the U.S. have increased dramatically as artificial lighting at night has become more common.

The secret allure of moss

Though it lacks the aromatic flowers of flashier plants, moss manages to emit subtle, enticing scents that help it spread its seed. Botanists have long thought that moss relied solely on wind and water to transport sperm from male plants to female ones. So they “were extremely surprised” to discover that female mosses give off “an amazing array of scents” that draw in tiny arthropods such as mites and springtails, which act “like pollinators,” biologist Sarah Eppley of Oregon’s Portland State University tells Phys.org. The ancestors of both mosses and arthropods date back some 450 million years, making them among the first life forms on Earth to establish themselves on land. The new evidence that they may have developed in concert with one another will likely “expand ideas about how plants evolved” and could help explain the existence of flowers and bees and other pollinating insects, Eppley says. Researchers next hope to learn what benefits, if any, the arthropods glean from their efforts.