Proving that what people throw away on land doesn't always stay there, scientists at Monterey Bay Aquarium Research Institute in California have published the results of a study of trash on the deep seafloor. Pictured is one example of such refuse, a tire on a ledge in Monterey Canyon that rests 2,850 feet (868 meters) below the surface.
To conduct the study, lead author Kyra Schlining and her coauthors combed through 18,000 hours of underwater video collected by the aquarium's remotely operated vehicles (ROVs).
But the process wasn't as tedious as it might sound: Monterey Bay technicians had already logged every bit of debris recorded in the footage over the past 22 years. So Schlining and colleagues were able to search the database and compile the results.
The team counted over 1,500 examples of deep-sea debris, going as deep as 13,123 feet (4,000 meters). They found items at dive sites from Vancouver Island to the Gulf of California, and as far west as Hawaii.
But to get a more nuanced picture of the debris, the scientists focused on an area they know quite well: the floor of Monterey Canyon.
Monterey Canyon stretches 95 miles (153 kilometers) through Monterey Bay into the Pacific Ocean. It reaches depths of up to 11,800 feet (3,600 meters) below the surface of the sea, although the actual canyon is only about 1 mile deep from the surrounding seafloor, making it comparable to the Grand Canyon. Monterey Canyon gets a steady influx of nutrients and is known to host rich biodiversity.
By studying the trash in the canyon, the scientists hope to begin to understand how marine debris accumulates and what impacts it may have on the ecosystem. (Related: "Pictures of Deep-Sea Creatures.")
In a release, Schlining said the most frustrating part of the project for her was that most of the ocean refuse the scientists found—things like glass, metal, paper, and plastic—could have been recycled but instead ended up in the sea.
In the conclusion to their paper, the scientists wrote, "Ultimately, preventing the introduction of litter into the marine environment through increased public awareness remains the most efficient and cost-effective solution to this dilemma."
—Brian Clark Howard