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      What leads rivers to suddenly change course?

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      Shifting is in a river’s nature. But when a river breaks free of its channel and carves a new path across the landscape, devastating floods may descend upon communities with little to no warning.

      For decades, researchers have struggled to explain exactly how river channels become primed for such sudden diversions, or avulsions. A study published September 18 in Nature may have finally quelled the debate, showing how two factors work together to stage the rerouting of a river. Building on their findings, the researchers also developed a promising algorithm that can predict the new path of a river that has avulsed. More

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      Climate change fueled the fury of hurricanes Helene and Milton

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      Meteorologists have watched in awe as Hurricane Milton, churning over the anomalously warm waters in the Gulf of Mexico, swiftly transformed into one of the strongest Atlantic storms on record.

      Over just 20 hours on October 7, Hurricane Milton explosively intensified from a Category 1 to a catastrophic Category 5 storm, with sustained winds of 290 kilometers per hour (180 miles per hour). The storm is expected to make landfall on the west coast of Florida either late on October 9 or early October 10 as a major Category 3 or 4 hurricane, bringing deadly storm surge and hurricane-force winds to coastal regions still reeling from Hurricane Helene just two weeks earlier (SN: 10/1/24). More

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      A transatlantic flight may turn Saharan dust into a key ocean nutrient

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      As dust from the Sahara blows thousands of kilometers across the Atlantic Ocean, it becomes progressively more nutritious for marine microbes, a new study suggests.

      Chemical reactions in the atmosphere chew on iron minerals in the dust, making them more water soluble and creating a crucial nutrient source for the iron-starved seas, researchers report September 20 in Frontiers in Marine Science.

      Dust clouds settling on the Atlantic can spawn phytoplankton blooms that support marine ecosystems, says Timothy Lyons, a biogeochemist at the University of California, Riverside. “Iron is incredibly important for life,” he says. Phytoplankton require it to convert carbon dioxide into sugars during photosynthesis. More

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      Some tadpoles don’t poop for weeks. That keeps their pools clean

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      Some tadpoles don’t poop for the first weeks of their lives. At least, that’s the case for Eiffinger’s tree frogs (Kurixalus eiffingeri), scientists report September 22 in Ecology.

      Eiffinger’s tree frogs are tiny frogs that live in Taiwan and on two Japanese islands: Ishigaki and Iriomote. The tree-dwelling amphibians lay their eggs in puny puddles, which are often nestled in plant stems, tree hollows and bamboo stumps.

      Once the tadpoles hatch, they spend their early lives in these puddles. However, in pools as small as these, there’s not a lot of water to dilute ammonia — a toxic chemical animals release when they pee or poop.

      Bun Ito and Yasukazu Okada, biologists from Nagoya University in Japan, now have uncovered the tadpoles’ secret sanitation strategy — self-induced constipation. The tadpoles store their poop in an intestinal pouch until they start to metamorphize into full-fledged frogs.

      The tadpoles of Eiffinger’s tree frogs (Kurixalus eiffingeri) spend their first few weeks of life in tiny puddles of water nestled within tree hollows and bamboo stumps.Bun Ito

      Ito and Okada raised tadpoles from four different frog species in makeshift nurseries. Once the experiment began, they moved the tadpoles to smaller cribs, plastic cases with a little more than a tablespoon of water. The team measured and compared how much ammonia each species released. They also measured the amount of ammonia each species stored in their guts.

      Eiffinger’s tree frog tadpoles released less than half as much ammonia on average than the species that released the most. And compared with two of the other species, the tadpoles kept more ammonia in their guts. The researchers note that unlike Eiffinger’s tree frogs, the other species typically lay their eggs in open ponds where ammonia is easily diluted. More

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      A hurricane’s aftermath may spur up to 11,000 deaths

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      Meghan Rosen is a staff writer who reports on the life sciences for Science News. She earned a Ph.D. in biochemistry and molecular biology with an emphasis in biotechnology from the University of California, Davis, and later graduated from the science communication program at UC Santa Cruz. More

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      Why Hurricane Helene was so devastating

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      A perfect storm of climate, geologic and geographic conditions have combined to make Hurricane Helene one of the most devastating storms to ever hit the United States. Days after it slammed into Florida’s Big Bend region on September 26 and traveled hundreds of kilometers inland, Helene’s destructive impact has continued to grow.

      Fueled by warm water in the Gulf of Mexico, which climate change made hundreds of times more likely, the tempest rapidly intensified offshore. By the time Helene came onshore as a Category 4 storm, its wind speeds surpassed 209 kilometers per hour (130 miles per hour) (SN: 9/27/24). More

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      A thousands-year-old log demonstrates how burying wood can fight climate change

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      In 2013, Ning Zeng came across a very old, and ultimately very important, log.

      He and his colleagues were digging a trench in the Canadian province of Quebec, one that they planned to fill with 35 metric tons of wood, cover with clay soil, and let sit for nine years. The team hoped to show that the wood wouldn’t decompose, a proof-of-concept that burying biomass could be a cheap way to store climate-warming carbon. But during excavation, they unearthed a pristine, twisted log that was very old, older than anything they could have possibly produced in their experiment. More

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      A vital ocean current is stable, for now

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      The ocean’s circulatory system may not be doing as poorly as previously thought.

      A vital ocean artery known as the Florida Current, a bellwether for the ocean’s ability to regulate Earth’s climate, has seemingly been weakening for decades. But that recent decline might not be quite as severe as suspected. The current has actually remained stable over recent decades, researchers report September 5 in Nature Communications.

      A previously reported decline in the flow had prompted speculations that a major system of ocean currents — known for regulating Earth’s climate — may have weakened recently due to human-caused climate change. Some researchers have suggested that the larger system, known as the Atlantic Meridional Overturning Circulation, or AMOC, could collapse sometime this century, dramatically cooling the northern hemisphere and raising the sea level along some Atlantic coastlines by up to 70 centimeters. More