Deep Sea ROVs Observe Trashed Ocean Floor [VIDEO]

Despite parts of the deep sea being as inaccessible as the Moon, humans have managed to litter the ocean floor with a variety of man-made garbage, the extent of which is far-reaching.

Recently published research by the Monterey Bay Aquarium Research Institute (MBARI) documents 22 years of evidence of human debris in the deep sea, with evidence of litter found to 13,000 feet (3,962 m) deep and 300 miles (480 km) off shore.

Plastic, metal, glass, rope and fishing debris constituted the most common anthropogenic debris found in the deep sea, with a sixth category created for "unidentifiable" debris, though less frequent occurrences of larger debris like abandoned research and military equipment and a shipping container were also documented.

The MBARI research focused on data gathered by ROVs (remotely operated vehicles) over the last two decades from the Monterey Canyon system. Beneath Monterey Bay, along the Central California coast, the Monterey, Soquel and Carmel Canyons comprise a canyon system comparable to the depths of the Grand Canyon in Arizona.

In the Monterey Bay region, the MBARI scientists documented 1,150 pieces of debris on the sea floor. ROV footage from deep sea regions off the coasts of Southern California, Vancouver Island and the Hawaiian Islands were also included in the study, bringing the total number of documented sea floor debris to more than 1,500. Plastic was by far the most common type of debris recorded; a third of the man-made debris reported was plastic, with plastic bags taking up half of all documented plastic.

Metals were the second most common, with aluminum, steel and tin cans being the most frequently documented metallic debris.

"I was surprised that we saw so much trash in deeper water. We don't usually think of our daily activities as affecting life two miles deep in the ocean." Kyra Schlining, lead author of the study, said in a news release. "I'm sure that there's a lot more debris in the canyon that we're not seeing. A lot of it gets buried by underwater landslides and sediment movement. Some of it may also be carried into deeper water, farther down the canyon."

It's too expensive and impractical to retrieve the debris, the researchers said, and since plastic and metal don't really biodegrade over time, it's possible the debris will remain on the seafloor for thousands of years, said MBARI senior researcher Susan von Thun, who spoke with Monterey County Herald newspaper.

"We've only explored less than one percent of the Monterey Canyon. We've seen garbage in the deep sea everywhere we've gone," she said. "It's really hard to estimate how much is out there."

The only way to address the issue, von Thun said, is to reduce the use of single-use items and stop littering.

The open-access research paper is available on Science Direct.