February 21, 2025: Penguins for tracking mercury, how a bad night's sleep can ruin your mood, and where curly hair comes from. —Andrea Gawrylewski, Chief Newsletter Editor | | | Malte Mueller/Getty Images | | | • News fatigue is real and here's the science behind it. Plus, expert advice to take control and protect your well-being while staying engaged. | 8 min read | | | • A number of safety documents containing the word "diversity" were removed from the Department of Labor website. They dealt with diverse size and shape of firefighters—details that help them properly fit into safety equipment like ventilator masks. | 3 min read | | | Gentoo penguins have a wide geographic range, making them good targets for follow-up research. David Merron Photography/Getty Images | On his first visit to Antarctica, polar researcher at Rutgers University Philip Sontag brought back a huge bag of penguin feathers. In the years since, his team of researchers has devised a way to use penguin feathers to track mercury levels in real-time in Southern Hemisphere wildlife. In a recent study, they measured both levels of mercury in the feathers of seven species of penguin and of carbon isotope-13 (which can indicate where the birds are geographically). They found that penguins that venture further north are exposed to more mercury. How it works: Mercury is a common by-product of gold mining, a growing industry in several southern countries. Small fish or other organisms consume the toxic metal. Those animals are eaten by bigger animals, and the mercury accumulates as it moves up the food chain. The substance binds with amino acids in animals and then infiltrates their central nervous systems, where it can inhibit neural growth. Many predators, including penguins, have clever ways of ejecting mercury from their bodies—the metal builds up in their feathers and they molt them off.
What the experts say: Rather than measuring the chemical itself in a snapshot of time and place, penguin feathers' mercury levels could be a bioindicator that tracks the substance's movement through the oceanic food web, says John Reinfelder, a marine biologist at Rutgers. | | | In volatile times, sleep becomes more important than ever. Even in otherwise healthy individuals, just one night of sleep deprivation can trigger a spike in anxiety and depression the next day. People who suffer from chronic sleep disruption tend to experience daily events as more negative, making it hard to escape a gloomy mindset.
How it works: Studies using MRI revealed that activity in the prefrontal cortex drops drastically with lack of sleep, as does the link between the prefrontal cortex and the amygdala. Neural impairment can occur after people experience just one night of sleep deprivation or routinely get less than six hours of sleep—or when participants' sleep is restricted to only four hours a night for five nights. As a result, the threshold for what the brain deems emotional becomes significantly lower when the amygdala can not act in concert with the prefrontal cortex.
Why the experts say: "Our societies should critically examine structures—such as work norms, school cultures and the lack of support for parents or other caregivers—that prevent people from getting enough rest," writes Eti Ben Simon, a research scientist at the University of California, Berkeley. | | | If you're enjoying all the science we cover in this newsletter, dive deeper with a subscription to Scientific American. You'll have access to all our articles and will be supporting crucial science journalism. | | | • Teen mental health is in crisis; 40 percent surveyed in 2023 by the CDC reported feeling sad and hopeless recently. Nine percent had attempted suicide. Therefore, it's particularly troubling that a recent executive order issued by the Trump Administration targeting chronic disease in children described prescription medications for mood and behavior disorders as a "threat," writes Megha Satyanarayana, chief opinion editor at Scientific American. "That language stigmatizes families who choose prescription medication to treat their struggling children. It undermines the expertise of medical professionals. And it opens the door for unproven, improperly studied treatments to gain legitimacy," she says. | 5 min read | | | Test your scientific knowledge with this week's quiz. Also, don't miss today's Spellements. If you spot any science words missing from the puzzle, email them to games@sciam.com. This week, Martin H. spotted lidar, which is an acronym of "light detection and ranging," a way of using light pulses to examine the surface of Earth. Excellent work, Martin! | | | MOST POPULAR STORIES OF THE WEEK | | | • Why Aren't We Losing Our Minds Over the Plastic in Our Brains? | 5 min read | • Men Actually Crave Romantic Relationships More Than Women Do | 2 min read | • Quantum Simulation Shows How Universe-Destroying 'Bubbles' Could Grow| 4 min read
| | | How do you cope with stressful times? One option is losing yourself in a good read with scientific chops; it can improve memory and build neural connections in adults. And studies find that reading for pleasure can reduce stress and improve mental health. Take some time this weekend to relax and check out one of this year's "microhistories" on science and society (compiled by Scientific American's own book maven, Briane Kane). | However you relax, enjoy the weekend and send any comments and questions about the newsletter to: newsletters@sciam.com. Until Monday. | —Andrea Gawrylewski, Chief Newsletter Editor | | Subscribe to this and all of our newsletters . | | | | Scientific American
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