Microplastics Found in Coral; The ‘Missing Plastic Problem

New Detection Technique Reveals Microplastics in Coral Skeletons, Shedding Light on the ‘Missing Plastic Problem’

Researchers from Japan and Thailand have discovered that microplastics are present in all three components of coral anatomy—surface mucus, tissue, and skeleton—using a novel detection technique applied to coral for the first time. These findings could help explain the “missing plastic problem,” where about 70% of plastic litter in oceans remains unaccounted for. The team suggests that corals may act as a “sink” for microplastics by absorbing them from the ocean, with their results published in *Science of the Total Environment*.

Humanity’s reliance on plastics has introduced significant convenience but has severely harmed ecosystems. Each year, an estimated 4.8 to 12.7 million tons of plastic enter the oceans. In Southeast Asia alone, approximately 10 million tons of plastic waste are dumped annually, contributing to this pollution.

To investigate this issue, Kyushu University’s Research Institute for Applied Mechanics partnered with Thailand’s Chulalongkorn University in 2022 to create the Center for Ocean Plastic Studies. Led by Professor Atsuhiko Isobe, the research team focused on the coral reefs around Si Chang Island in the Gulf of Thailand, a known area for both reefs and anthropological studies.

The research involved developing a method to extract and identify microplastics from coral samples. The team collected 27 samples from four coral species and discovered 174 microplastic particles, mostly sized between 101–200 μm—about the width of a human hair. The predominant types of microplastics identified were nylon, polyacetylene, and polyethylene terephthalate (PET).

These findings suggest that corals could help account for the missing plastic by sequestering plastic waste from the ocean, akin to how trees absorb CO2. Since coral skeletons remain intact post-mortem, the trapped microplastics could be preserved for centuries.

Further research is essential to understand the implications of these findings for coral reefs and the broader ecosystem. “To accurately assess the situation, we need extensive global studies across various coral species,” concluded Isobe, noting that the effects of microplastics on coral health and the reef community remain largely unknown.