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SPONSORED BY  | | December 17, 2024: The ocean's carbon-eating bacteria, the wildest discoveries about human health, and sometimes evolution goes backward. —Andrea Gawrylewski, Chief Newsletter Editor | | | Unfurling fiddlehead of the Christmas fern (Polystichum acrostichoides). Danita Delimont/Alamy Stock Photo | | | • Many types of ferns–one of the oldest groups of plants on Earth–at times evolve "backward" to less specialized forms. | 5 min read | | | • Short sleepers, who only require four to six hours of sleep a night, are genetically wired to function on less shut-eye. | 7 min read | | | Scientists made remarkable discoveries about the human body in 2024. I've summarized a few of the most fascinating findings below, but you can read our full list here. New pain medication: A new type of pain medication is heading toward the market. The drug, called suzetrigine, blocks peripheral nerve channels and stops pain signals from reaching the brain. It does not carry a risk of addiction like opioids. Vertex Pharmaceuticals, the company that makes the drug, applied for U.S. Food and Drug Administration approval of it earlier this year.
Bouts of aging: A study showed that people experience dramatic aging shifts in their mid-40s and 60s. People in their 40s and 60s displayed differences in molecules and markers that seem to be linked to muscle weakness and loss, declines in heart health, and a lessened ability to metabolize caffeine. Forty-somethings start breaking down fats and alcohol less efficiently, and in their 60s people's immune systems weaken.
Human lifespan limit: Human longevity may have a theoretical upper limit, new research has found. After increasing for much of the 20th century, life expectancy gains are slowing down or reversing in many countries, suggesting human lifespan may have plateaued. Aging—a series of poorly understood biological processes whose effects include frailty, dementia, heart disease and sensory impairments—has so far eluded efforts to slow it down, says S. Jay Olshansky, a professor of public health at the University of Illinois at Chicago. | | | From the top layer of the ocean, a "marine snow" of dead plankton, excrement and other particles is constantly drifting down toward the ocean floor. As it sinks, bacteria feed upon it, carrying it ever deeper. Marine biologists isolated and tested bacterial populations in marine snow and found that specific microbe populations prefer to eat dead phytoplankton that contain specific kinds of fatty acid biomolecules called lipids.
Why this matters: The oceans absorb billions of tons of carbon every year. And scientists hope to understand precisely how that process happens. Measuring the rate of carbon absorption means investigating the dietary preferences of the microbes digesting that carbon. Lipids constitute up to 30 percent of the particulate organic matter at the ocean's surface, so the bacterial dietary preferences in a region could have a significant impact on how much carbon-containing biomass sinks to the seafloor.
What the experts say: "If we can start to understand what [microbes] can do, then we can imagine a future where we can start to predict, potentially, the fate of carbon based on the organisms that are present," says Benjamin Van Mooy, a researcher at Woods Hole Oceanographic Institution. | | | SPONSORED CONTENT BY NMDP | | | The Future of Blood Stem Cell Transplant Is Here | | | Blood stem cell transplants using cells from a donor offer a promising cure for people with blood cancers or disorders. Before, not everyone had a suitable donor, leaving many without options for a cure. Now science is changing what's possible. Learn more. | | | • The world's democracies are shifting from a focus on equality and representation to an emphasis on individual rights and freedoms, writes Piergiuseppe Fortunato, an economist at the United Nations Conference on Trade and Development. This evolution has contributed to the rise of populism and cultural conflicts in society which feed a divisive political landscape, with competing factions prioritizing their own interests and values over collective goals and social cohesion, Fortunato says. | 7 min read | | | Revisiting the editors' favorite science stories of 2024. | | | • Sand is a main ingredient in concrete, glass and electronics. Sand mining is the world's largest extraction industry. Demand is predicted to rise in the coming decades, outstripping supply and even nature's ability to replenish sand. Illegal sand extraction is ravaging deserts across countries like Kenya and Morocco. Sand from Moroccan beaches and dunes is sold inside the country and is also shipped abroad, using organized crime's extensive transport networks. | 15 min read | | | Considering that we humans have been studying our bodies, anatomy and health for thousands of years, it's remarkable that science has so much yet to learn. In just the last few years new evidence has upended long-held assumptions about human metabolism, women's health and even the inheritance of trauma. What we humans Know (capital K) is infinitesimal compared with what can be known. | I love hearing from you. Keep sending feedback, reflections and suggestions to: newsletters@sciam.com. Until tomorrow! | —Andrea Gawrylewski, Chief Newsletter Editor | | Subscribe to this and all of our newsletters . | | | | Scientific American
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