Researchers found nuclear particles inside crustaceans living seven miles below sea level, including in the remote depths of the Mariana Trench.
The effects of nuclear bomb tests during the Cold War continue to influence our planet, including even those creatures living 36,000 feet below sea-level. According to a new study, researchers discovered that amphipods, a sort of deep-sea crustacean, had more radioactive carbon in their muscle tissue than there is radioactive carbon in their surrounding environment.
“Biologically, [ocean] trenches are taken to be the most pristine habitats on Earth,” said Weidong Sun, a geochemist at the Institute of Oceanology in China and co-author 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.”
The study, which was published in the journal Geophysical Research Letters, documented how explosion particles of carbon-14 from nuclear bomb tests still managed to find its way into the guts of tiny crustaceans living tens of thousands of feet beneath the ocean’s surface.
From 1945 to 1963 nearly 500 nuclear bombs, 379 of which exploded in the atmosphere, were detonated mainly by the U.S. and the Soviet Union. These tests dramatically increased the amount of carbon-14 on our planet which was then absorbed by both ocean and land-based life — including those life forms in even the hardest-to-reach surfaces of our planet. It was not until the Test Ban Treaty of 1963 that these atmospheric and underwater nuclear tests stopped. However, our planet has not quite recovered from the events. In fact, the carbon-14 levels in our air are still higher than they were before the testing started, even decades after the tests ended.
According to Smithsonian Magazine, the team collected amphipods from the Mussau Trench, New Britain Trench, and the Mariana Trench which is the deepest in the world at over seven miles below the surface.
The team had initially intended to study the crustaceans in relation to their shallow-water relatives and found that these deep-sea critters tended to grow larger and live longer than their counterparts in shallower waters. Amphipods that live in shallow water typically live for less than two years and grow to an average length of about less than one inch. But amphipods that inhabit the ocean’s deep trenches were more than 10 years old and reached a length of 3.6 inches.
The researchers suspect that the deep-sea amphipods are bigger and live longer because they have had to evolve in a harsher environment. In order to survive in the deep-sea’s low temperatures, high pressure, and limited food supply, the crustaceans must have developed a slower metabolism and lower cell turnover. These traits then allowed the creatures to store energy for longer periods of time, but it also meant that the carbon-14 took longer to metabolize and leave their bodies.
In order to reach these incredible depths to collect their specimens, researchers relied on two Chinese research vessels equipped with baited traps to gather the crustaceans. Analysis of their muscle tissue and gut contents found elevated levels of carbon-14.
Scientists concluded that the carbon-14 was consumed by these deep-sea creatures after they consumed contaminated carcasses of dead marine animals that floated down from the ocean’s surface to the ocean’s floor. In this way, nuclear particles were taken up by the deep-sea crustaceans.
Alarming those this discovery may be, not all experts are surprised. Indeed, toiletries have been found flushed two miles beneath the surface and other human detritus, like metals and plastic trash, have been spotted in more than 30 deep-sea canyons off the east coast of the United States. Nonetheless, the fact that the atomic signature from these nuclear bombs has reached the most remote depths of the ocean shows the breadth of reach that harmful human activity can have on our environment — even where we least expect it.
After learning about the discovery of amphiphods with nuclear particles in their gut, read the story of the first-ever Australian deep sea investigation. Next, learn about the mysterious sound that scientists found emanating from the Mariana Trench.