Surprisingly large amounts of discarded trash end up in the ocean. Plastic bags, aluminum cans, and fishing debris not only clutter our beaches, but accumulate in open-ocean areas such as the "Great Pacific Garbage Patch." Now, a paper by researchers at the Monterey Bay Aquarium Research Institute (MBARI) shows that trash is also accumulating in the deep sea, particularly in Monterey Canyon. Kyra Schlining, lead author on this study, said, "We were inspired by a fisheries study off Southern California that looked at seafloor trash down to 365 meters. We were able to continue this search in deeper water -- down to 4,000 meters. Our study also covered a longer time period, and included more in-situ observations of deep-sea debris than any previous study I'm aware of."

To complete this extensive study, Schlining and her coauthors combed through 18,000 hours of underwater video collected by MBARI's remotely operated vehicles (ROVs). Over the past 22 years, technicians in MBARI's video lab recorded virtually every object and animal that appeared in these videos. These annotations（释文） are compiled in MBARI's Video Annotation and Reference System (VARS).

For this study, video 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.

The largest proportion of the debris -- about one third of the total -- consisted of objects made of plastic. Of these objects, more than half were plastic bags. Plastic bags are potentially dangerous to marine life because they can smother attached organisms or choke animals that consume them.

Metal objects were the second most common type of debris seen in this study. About two thirds of these objects were aluminum, steel, or tin cans. Other common debris included rope, fishing equipment, glass bottles, paper, and cloth items.