Plastic waste entering oceans each year totals around 11 million tons and breaks into microplastics carried by currents across marine systems. These particles harm sea life and can reach human food supplies. Past research covered coastal and surface waters, yet data on the deep sea, which makes up nearly 90 percent of ocean areas, stayed limited. Hydrothermal vent habitats in particular had seen little examination for such pollution.
Scientists from the Korea Research Institute of Bioscience and Biotechnology, working with the Korea Institute of Ocean Science and Technology, performed the first side-by-side analysis of microplastic levels in vent animals from two ocean regions. They examined snails and mussels gathered from sites more than 2,000 meters deep in the North Fiji Basin of the southwestern Pacific and the Central Indian Ridge in the Indian Ocean.
Microplastics appeared in 92 percent of the specimens, averaging 3.42 particles each. Polystyrene ranked as the most common type found. Grazing snails held most particles in digestive organs, while filter-feeding mussels showed even spread through tissues. This points to feeding habits shaping accumulation patterns.
Specimens from the Indian Ocean held up to 14.7 times more microplastics by body weight than those from the Pacific. Variations in nearby human activity, river inputs and ocean flows likely explain the gap.
The results supply the first proof that surface plastic reaches extreme deep-sea vents. They also show how organism traits and local conditions affect contamination levels. The work may aid future monitoring, impact studies for seabed mining and protection plans for deep ecosystems.
