April 18, 2024: Coral reef bleaching event, brainwave balance and mental health, and a black hole near Earth. —Andrea Gawrylewski, Chief Newsletter Editor | | | Earth is experiencing its fourth mass coral bleaching event, according to an announcement released by the U.S. National Oceanic and Atmospheric Administration and the International Coral Reef Initiative. This year, 75 percent of the Great Barrier Reef–which is the size of Italy or Japan–has bleaching. In the Caribbean and particularly the Florida Keys, scientists can no longer assess the extent of bleaching from fly-over data gathering (a common way to determine bleaching rates) because there aren't enough corals left to evaluate.
How it works: Corals reefs are built by invertebrate marine animals that secrete calcium carbonate to form a hard skeleton. They get their color from photosynthetic microbes that live symbiotically in their tissue–the corals provide the microbes safety, while the microbes offer the corals nutrients and energy from photosynthesis. In times of stress, the coral rejects its symbionts, which is called bleaching, because all the colorful microbes are booted from the coral. If the stress persists, the coral polyp dies. For more than a year, global sea-surface temperatures have been at record highs in many areas. "For corals, it's been a disaster," says Terry Hughes, a marine biologist at James Cook University in Australia.
What the experts say: "A mass bleaching event is, by definition, a mass mortality event," says Hughes. And the only way to save corals is to stabilize ocean temperatures by curbing warming. "The reality is: we are losing literally billions of corals on the world's coral reefs."
More on corals: What's Happening in the Ocean and Why It Matters to You and Me | 5 min read
Coral Reefs Are Struggling, but There Is Some Good News | 3 min read
Extreme Summer Heat Threatens Coral Replanting Effort | 5 min read
| | | A map showing NOAA predictions for where corals will bleach in the coming days, with darker areas representing higher levels of concern. NOAA Coral Reef Watch | | | Different cortical regions of the human brain generate distinct brainwaves. A new study shows that rapid gamma waves often originate in outer layers of the brain, whereas slower alpha and beta waves arise in the deeper ones. Neuroscientists observed similar results across 14 cortical regions and four mammalian species, including humans. Each brain layer is less than a millimeter thick and difficult to record from individually—so the study authors used probes containing multiple electrodes to measure all layers at once. An algorithm helped them pinpoint the origin of the waves, and anatomical studies confirmed the findings.
Why this is interesting: Outer layers of the brain seem to process sensory input, whereas deeper layers control what the brain does with the resulting information. The researchers believe that imbalances of information processing among brain regions could be behind neuropsychiatric disorders.
What the experts say: "We believe it's literally the balance between your brain processing incoming sensory information and its control over that information," that determines healthy brain function, Miller says. For instance, if higher frequencies dominate (meaning the brain is processing sensory information excessively), this could cause attention problems or sensory overload. | | | • Astronomers have discovered a black hole shockingly close to Earth. | 5 min read | | | • Online age verification laws are intended to protect children from explicit or harmful content. But some experts worry they will put private data at risk. | 6 min read | | | • A good old-fashioned guilt trip built into public messaging could be a powerful tool for encouraging change, researchers find. | 7 min read | | | • A record 2.1 million people in North and South America have been infected this year with dengue fever. | 3 min read | | | A worker fumigates a house against the Aedes aegypti mosquito to prevent the spread of dengue fever in a neighborhood in Piura, northern Peru. Ernesto Benavides/AFP via Getty Images | | | • Movies and TV shows get a lot right when it comes to the science of space and physics, or even biology, write Deena Weisberg and Marc Coutanche, both associate professors of psychology. But when it comes to brain science, they say, story plots are riddled with inaccuracies. Why? "We tend to assume that we're already experts on how our mind works, relying on our unscientific intuitions," they say, and so screenwriters don't seek out expert consultants as frequently when it comes to brain science. But it matters when movies and shows get things wrong: "these portrayals powerfully shape public perceptions of how the mind works," they write. | 4 min read | | | If you're lucky enough to have been snorkeling or scuba diving, you may relate to the sorrow that researcher Terry Hughes described to Scientific American staff writer Meghan Bartels at seeing so many dead or bleached corals. Coral reefs support a tremendous diversity of plant and animal species, so losing the corals has a vast ripple effect on marine habitats around the world. | Thank you for being part of our circle of science-curious readers! Email me anytime: newsletters@sciam.com. I read all your notes and respond to many. See you tomorrow. | —Andrea Gawrylewski, Chief Newsletter Editor | Reader Michael Coleman in South Burlington, Vt., captured this photo on April 8 of the partially eclipsed sun through binoculars onto the shadow of his hand. Michael Coleman | | | | Subscribe to this and all of our newsletters . | | | | Scientific American
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