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24 April 2014 11:45 am ,
Vol. 344 ,
Major climate data sets have underestimated the rate of global warming in the last 15 years owing largely to poor data...
The tsetse fly is best known as the vector for the trypanosome parasites that cause sleeping sickness and a disease in...
The National Institutes of Health is revising its "two strikes" rule, which allowed researchers only one chance to...
By stabilizing the components of retromers, molecular complexes that act like recycling bins in cells, a recently...
Fossil fuels power modern society by generating heat, but much of that heat is wasted. Semiconductor devices called...
Researchers are gaining insights into what made Supertyphoon Haiyan so powerful and devastating through post-storm...
Millions around the world got a first-hand look at what it was like to be in Tacloban while it was pummeled by...
- 24 April 2014 11:45 am , Vol. 344 , #6182
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ScienceShot: Mysterious Underwater Circles Explained
31 January 2014 3:30 pm
The truth behind the mysterious underwater circles that periodically appear off the coast of Denmark has been discovered, and sadly it doesn’t involve aliens, fairies, or the fabled lost city of Atlantis. In 2008, a tourist snapped photos of several large dark rings that appeared near the white cliffs of Denmark’s island of Møn in the Baltic Sea. The circles, several as large as a tennis courts, sparked numerous theories of their origin—some more outlandish than others. In 2011, when the formations reappeared, scientists discovered they were actually round bands of marine eelgrass, similar to rings of mushrooms known as fairy rings. Because eelgrass usually grows as continuous underwater meadows, scientists were still baffled by the rims of lush eelgrass with barren cores. Now, researchers say they at last know the rings’ true cause. The scientists found large amounts of toxic sulfide built up in the muds where the eelgrass grows. The sulfide forms when nutrients from agricultural runoff cause bacteria to flourish. Eelgrass grows radially outward, with older plants in the middle and younger seedlings on the outer rim. Because only the middle ring of mature plants can endure the poisonous sulfide, a near-perfect ring of seagrass forms, the researchers report in the February issue of Marine Biology. While the eelgrass circles make for a remarkable sight and a catalyst for kooky conspiracy theories, the researchers say sulfide from agricultural runoff has become a major problem for seagrass ecosystems worldwide.
For more stories on mysterious formations in nature, see our collections page.