Radioactive carbon from nuclear bomb tests found in ocean’s deepest trench – CNET
Earth isn’t naturally rich in carbon-14, but it is present in living organisms and accounts for just trace amounts of carbon in the natural world. Nuclear tests in the mid-20th century doubled the amount of carbon-14 in the atmosphere and eventually this fell to the surface — including the surface of the ocean.
Scientists found carbon-14 levels in amphipod muscle tissue, at some of the deepest points on Earth, including the Mariana trench, was much higher than the levels of carbon-14 in organic matter at the same depth. And the contents of the amphipods “stomachs” showed levels of carbon-14 similar to the levels founds at the surface of the Pacific Ocean. Their findings suggest the tiny crustaceans have a preference for feeding on organisms that float down from the surface.