Researchers sampled amphipods from the Pacific Ocean’s Mariana and Kermadec trenches

Scientists discover high levels of contamination in amphipods

Crustaceans from the deepest parts of the ocean have been found to contain 10 times the level of industrial pollution than the average earthworm.

Writing in the journal Nature Ecology and Evolution, scientists describe how they found high levels of Persistent Organic Pollutants (POPs) in the fatty tissue of amphipods.

These include polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethos (PBDEs) which are commonly used as electrical insulators and flame retardants.

The team from Newcastle University, the University of Aberdeen and the James Hutton Institute say the next step is to understand the consequences of this contamination and what the knock-on effects might be for the wider ecosystem.

“We still think of the deep ocean as being this remote and pristine realm, safe from human impact, but our research shows that, sadly, this could not be further from the truth,” commented lead author Dr Alan Jamieson.

“In fact, the amphipods we sampled contained levels of contamination similar to that found in Suruga Bay, one of the most polluted industrial zones of the north-west Pacific.

“What we don’t yet know is what this means for the wider ecosystem and understanding that will be the next major challenge.”

Before PCBs were banned in the 1970s, the total global production of these chemicals was in the region of 1.3milliion tonnes.

In the study, researchers sampled amphipods from the Pacific Ocean’s Mariana and Kermadec trenches which are 10 kilometres deep and 7,000 kilometres wide.

The researchers suggest that the pollutants most likely found their way to the trenches through contaminated plastic, debris and dead animals sinking to the bottom of the ocean. The amphipods then consume the debris, which in turn become food for larger animals.

“The fact that we found such extraordinary levels of these pollutants in one of the most remote and inaccessible habitats on earth really brings home the long-term, devastating impact that mankind is having on the planet,” continued Dr Jamieson. “It’s not a great legacy that we’re leaving behind.”

Image (C) Hans Hillewaert.