Researchers diving into one of the ocean’s most remote realms uncovered evidence that human pollution had arrived in an unexplored deep-sea canyon well before their scientific investigations. In a 2025 mission, an underwater robotic vehicle identified plastic waste, fishing debris, and assorted discarded materials more than 1,100 meters beneath the waves in Argentina’s Mar del Plata Submarine Canyon, as reported in the journal PLOS One.
Intended to assess deep-sea life, the expedition utilized the remotely operated vehicle SuBastian aboard the research ship Falkor(too). Over 17 dives within the canyon’s depths, scientists cataloged 29 pieces of anthropogenic litter, 27 of which were plastics, at depths reaching 3,820 meters.
These results highlight how even far-flung underwater environments are contaminated by human activities. Waste was found in areas distant from coastal zones, stirring inquiries into how offshore operations may funnel debris into deep ocean habitats.
Submarine Canyon Reveals Unexpected Human Impact
Submarine canyons are intense underwater landscapes where sediments, nutrients, and organic matter accumulate, fostering vibrant deep-sea ecosystems. The Mar del Plata Submarine Canyon lies offshore Argentina amidst the convergence of the warm Brazil Current and the cold Malvinas Current, creating complex hydrodynamic and sedimentary processes that shape the abyssal habitat.
The expedition’s primary target was studying seafloor creatures. Marine biologist Diego Urteaga from the Grupo de Estudios del Mar Profundo de Argentina (GEMPA) shared that the team’s focus unexpectedly shifted toward recording pollution: “The main goal of the expedition was to study deep-sea benthic biodiversity,” says marine biologist Diego Urteaga of the Grupo de Estudios del Mar Profundo de Argentina (GEMPA).
“However, the presence of marine litter was so evident that we felt it was important to document it and share our observations with the scientific community.”
Human waste wasn’t evenly scattered but clustered around canyon walls and in deeper channels, illustrating how underwater topography can trap and redistribute debris through currents.
Among the litter documented were a vivid instant noodle wrapper found at 1,920 meters, a nylon rope fitted with a hook at 1,949 meters, plus plastic bags, food wrappers, and discarded cups. These findings demonstrate that even remote deep-sea environments receive waste originating far from human settlements.
Origins of Deep-sea Pollution Investigated
Although pinpointing the exact sources of each debris piece was not feasible, the researchers identified indicators suggesting the litter came chiefly from maritime activities. The prevalence of fishing gear, durable food packing, and ship-related items implied vessels traversing open waters likely contribute significantly to this contamination.
“The characteristics of the litter we found are more consistent with waste generated by vessels operating offshore, particularly fishing vessels, than with urban sources,” Urteaga says.
“This suggests that human activities at sea may be a major contributor to the litter reaching the Mar del Plata Submarine Canyon.”
The canyon’s position makes it less probable that litter arrived directly from Argentina’s coast, as it is situated hundreds of kilometers offshore and separated from the continental shelf. Floating coastal rubbish would encounter substantial obstacles reaching these deep zones.
Litter appeared in ten of the 17 dives, concentrated in particular stretches of the canyon. Although debris counts were comparatively low next to some other submarine canyons globally, scientists cautioned this visible trash only scratches the surface.
Smaller particles hidden beneath sediments or outside the cameras’ range may be missed. Therefore, this survey offers a preliminary glimpse rather than an exhaustive assessment of pollution in the canyon.
Marine Life Adapts to Human Waste in the Abyss
The team also observed that deep-sea organisms are beginning to interact with human debris, incorporating it into their habitats. Arthropods clustered on a black plastic sheet, while sea stars and polychaete worms inhabited a plastic bag and nylon rope, illustrating how artificial objects become substrates within these untouched ecosystems.
“The colonization of litter by sessile organisms can turn human debris into an artificial substrate in the deep sea, potentially altering local communities,” Urteaga says.
“It may also provide a means for organisms to be transported beyond their natural distribution, although the ecological consequences of this process are still poorly understood.”
Previous research has documented marine creatures inhabiting floating plastics and other trash. However, long-term effects in deep-sea settings remain uncertain, largely due to limited knowledge of these intricate communities.
The amount of debris discovered in Mar del Plata Canyon was lower than in various coastal canyons. Marine biologist Daniel Lauretta of GEMPA noted the surprising outcome: “What surprised me the most was the relatively low quantity of litter, luckily,” says marine biologist Daniel Lauretta of GEMPA. “Before we started the ROV dives, I was expecting a much more polluted area.”
While some submarine canyons near coastlines have shown 50 to 80 litter pieces per kilometer, surveys in the Mar del Plata Canyon found fewer than three items per kilometer.
Probing One of the Ocean’s Final Frontiers
As outlined in the publication PLOS One, this research contrasts the excitement of exploring largely unknown underwater ecosystems with the harsh reality of pervasive human impact. Signs of human presence extend even to these remote abysses.
Urteaga hopes these insights will enhance understanding of how human practices affect scarcely explored habitats. “I hope our findings help raise awareness of the impact we are having on an environment that is both distant and largely unknown to us,” Urteaga says.
“We may already be altering deep-sea communities that we have barely begun to understand.”
The team intends to expand investigations to additional submarine canyons off Argentina’s coast, aiming to determine if litter contamination is widespread and how varying habitats cope with human detritus.
Moreover, the expedition allowed scientists to witness a scarcely observed realm. Despite covering most of Earth’s surface, vast sections of the deep ocean remain unexplored by human eyes.
“The possibility of observing life in waters so deep that sunlight is simply unknown is a frontier of knowledge that I have always dreamed of exploring,” Urteaga remarks.
“The deep sea encompasses most of our planet, yet it remains largely unknown, making it one of the last great frontiers of exploration and discovery.”
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