Since the Mariana Trench is the deepest part of the ocean, you might guess that it is safe from the impact of humans, but you would be wrong. Scientists have found that, despite its depth and remoteness, the deep sea contains levels of toxins that match some of the most polluted marine systems on earth.
According to a new study just published in the journal Nature Ecology and Evolution, man-made pollutants have reached the depths of two of the world’s deepest ocean trenches — the Mariana Trench in the North Pacific and the Kermadec Trench in the South Pacific, which are each miles deep and are separated by thousands of miles.
For the study, researchers from Newcastle University, the University of Aberdeen and the James Hutton Institute sent deep-sea landers to collect samples of small organisms living in the deepest level of the trenches and found troubling levels of toxic pollutants in small crustaceans, or amphipods.
The level found wasn’t the only concern. The types of toxins they found are considered persistent organic pollutants (POPs) that are known for staying in the environment for a long time. In this case, the two most prevalent ones were Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs).
Even though PCBs have been banned and PBDEs are heavily restricted, they’re still clearly a pervasive environmental problem that are making their way through the food chain.
In the Mariana trench alone, the highest concentrations of PCBs found were approximately 50 times greater than the levels that have been found in crabs living near the Liaohe River, one of most polluted waterways in China.
“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,” said Dr. Alan Jamieson, lead author of the study, who is based in the School of Marine Science and Technology at Newcastle University. …