Not surprising, but sad nonetheless
We’ve all seen images of trash on beaches, or floating on the surface of the ocean. But a surprising amount ends up on the deep seafloor, at depths so great that it’s been very hard for us to really know what the situation is. Because it’s no very practical to fund a deep sea mission just to look for trash, researchers at the Monterey Bay Aquarium Research Institute instead decided to comb through thousands of hours of video recorded by remotely controlled vehicles over the past 20+ years, specifically looking for debris.
For this study, research technicians searched the VARS database to find every video clip that showed debris on the seafloor. They then compiled data on all the different types of debris they saw, as well as when and where this debris was observed.
In total, the researchers counted over 1,500 observations of deep-sea debris, at dive sites from Vancouver Island to the Gulf of California, and as far west as the Hawaiian Islands. In the recent paper, the researchers focused on seafloor debris in and around Monterey Bay—an area in which MBARI conducts over 200 research dives a year. In this region alone, the researchers noted over 1,150 pieces of debris on the seafloor. (source)
About 1/3 of the trash were made of plastic, more than half of those being plastic bags, which are notoriously dangerous for marine life. Next were metal objects, at about 1/5 of the total. Other common debris included rope, fishing equipment, glass bottles, paper, and cloth items.
Because of deep sea conditions (very cold water, little oxygen, few bacteria), all of this trash will likely stick around much longer than it would do on the ground.