Radioactive carbon released into the atmosphere from 20th-century nuclear bomb tests has reached the deepest parts of the ocean, new research finds.  A new study in AGU’s journal Geophysical Research Letters finds the first evidence of radioactive carbon from nuclear bomb tests in muscle tissues of crustaceans that inhabit Earth’s ocean trenches, including the Mariana Trench, home to the deepest spot in the ocean.

Organisms at the ocean surface have incorporated this “bomb carbon” into the molecules that make up their bodies since the late 1950s. Crustaceans in deep ocean trenches are feeding on organic matter from these organisms when it falls to the ocean floor. The results show human pollution can quickly enter the food web and make its way to the deep ocean, according to the study’s authors.

According to researchers, water containing carbon-14 can take centuries to circulate throughout the ocean, but the food web drastically accelerated the process. “There’s a very strong interaction between the surface and the bottom, in terms of biologic systems, and human activities can affect the biosystems even down to 11,000 meters,” said Weidong Sun, a coauthor of the study, “so we need to be careful about our future behaviors.”

RADIOACTIVE CARBON FROM NUCLEAR BOMB TESTS FOUND IN DEEP OCEAN TRENCHES
AGU Press Release, 8 May 2019