Researchers documented 167 items on the floor of the Calypso Deep — about 3.2 miles (5.1 km) beneath the Mediterranean surface — with 148 classified as marine debris and 19 as human-made objects. A manned submersible captured images showing full rubbish bags and items apparently dumped from boats. Scientists warn the Hellenic Trench traps debris and, because deep-sea cleanup is currently impractical, litter may persist for decades. The team urges better waste handling, recycling and reductions in single-use plastics to curb the 1–2 million tonnes of plastic entering the oceans each year.
Scientists Find Trash at Mediterranean's Deepest Point: "Not a Single Inch of It Is Clean"
Researchers documented 167 items on the floor of the Calypso Deep — about 3.2 miles (5.1 km) beneath the Mediterranean surface — with 148 classified as marine debris and 19 as human-made objects. A manned submersible captured images showing full rubbish bags and items apparently dumped from boats. Scientists warn the Hellenic Trench traps debris and, because deep-sea cleanup is currently impractical, litter may persist for decades. The team urges better waste handling, recycling and reductions in single-use plastics to curb the 1–2 million tonnes of plastic entering the oceans each year.
01:54 PM, 11/14/2025Environment
Trash Discovered at the Bottom of the Mediterranean Raises Alarm
Littering frustrates many people, but new research shows that discarded waste has reached places once thought remote — including the deepest point of the Mediterranean Sea.
An international research team, reported by the Universitat de Barcelona, documented 167 individual items on the floor of the Calypso Deep, approximately 3.2 miles (about 5.1 km) beneath the sea surface. Of those objects, 148 were classified as marine debris and 19 were identified as items of human origin, one of the highest concentrations recorded at such great depth.
Researchers used a manned submersible off Greece's southwest coast to capture high-resolution images of the trench floor. Professor Miquel Canals of the Department of Earth and Ocean Dynamics at the Universitat de Barcelona said the footage showed full bags of rubbish and other items with clear signs they had been discarded from boats.
"Unfortunately, as far as the Mediterranean is concerned, it would not be wrong to say that 'not a single inch of it is clean,'" Canals said.
Improperly dumped waste can severely harm marine ecosystems: animals can become entangled in abandoned fishing gear, ingest plastic fragments, or be smothered by large objects that settle on the seabed. Some materials can also leach harmful chemicals that affect marine life and may move up the food chain.
Calypso Deep lies within the Hellenic Trench, a geological feature that tends to concentrate debris carried by ocean currents. Because human access to such extreme depths is limited and recovery operations are technically and financially difficult, much of this waste is likely to remain for decades, continuing to damage the ecosystem.
What can be done?
Addressing the problem begins on land. Better waste handling, stronger recycling practices for plastic, paper and glass, reducing single-use plastics and improving overall waste management can reduce the amount of material that reaches the sea. According to Our World in Data, roughly one to two million tonnes of plastic (about 1.1 to 2.2 million US tons) enter the oceans each year — a flow that can be reduced through collective action and policy change.
Takeaway: The discovery at Calypso Deep is a stark reminder that human-generated waste affects even the ocean’s most remote depths. Preventing further pollution requires practical steps at individual, industry and government levels.