Man-made pollutants found in Earth’s deepest ocean trenches

High levels of man-made pollutants have been found in the shrimp-like creature Hirondellea gigas (pictured), which lives in the deep-ocean Mariana Trench. Image courtesy of Daiju Azuma, CC-BY-SA.

Toxic chemicals are accumulating in marine creatures in Earth’s deepest oceanic trenches, the first measurements of organic pollutants in these regions have revealed.

“We often think deep-sea trenches are remote and pristine, untouched by humans,” says Alan Jamieson, a deep-ocean researcher at the University of Aberdeen, UK. But Jamieson and his colleagues have found man-made organic pollutants at high levels in shrimp-like crustaceans called amphipods that they collected from two deep-ocean trenches, he told a conference on deep-ocean exploration in Shanghai on 8 June.

“It’s really surprising to find pollutants so deep in the ocean at such high concentrations,” says Jeffrey Drazen, a marine ecologist and professor of Oceanography.

Before this work — which has not yet been published — the study of pollutants in deep-sea organisms had been limited to those that live at depths of 2,000 meters or less. The latest research tested for levels of organic chemicals in amphipods collected at 7,000–10,000 meters depth, from the Mariana Trench in the western Pacific Ocean — the world’s deepest trench — and from the Kermadec Trench near New Zealand.

Read more about it in Nature News.