Particles From Cold War Nuclear Bomb Tests Found in Deepest Parts of the Ocean
By Christopher Crockett Smithsonian.com
No place on Earth is free from human influence—not even the bottom of the deepest trenches in the ocean.
Shrimp-like critters from three West Pacific ocean trenches were found to munch on food that sinks down from the surface, leaving a unique chemical signature from decades-old nuclear bomb tests in the bodies of the deep-sea crustaceans. The findings, published recently in Geophysical Research Letters, not only help marine scientists figure out how these bottom dwellers survive, but also underscore the depths to which humanity’s influence can penetrate.
Deep ocean trenches may be among the least explored nooks on Earth. The deepest of these, the Mariana Trench in the Pacific Ocean, reaches down to about 36,000 feet below sea-level. (Mt. Everest could sit at the bottom, and its summit would still lie beneath more than a mile of water.) At the bottom, temperatures hover just above freezing and the water exerts a pressure more than 1,000 times that felt at the surface.
“Biologically, [ocean] trenches are taken to be the most pristine habitats on Earth,” says Weidong Sun, a geochemist at the Institute of Oceanology in China and coauthor of the new study. “We are interested in how life survives down there, what’s its food source, and whether human activities have any influence.”