Researchers have uncovered a significant discovery regarding microplastic pollution, revealing that all parts of coral—surface mucus, tissue, and skeleton—contain microplastics. A research team from Japan and Thailand, using a newly developed method for extracting and detecting microplastics, studied coral samples from the Gulf of Thailand. Their findings not only shed light on the contamination of marine ecosystems but also propose a solution to the long-standing 'missing plastic problem,' where roughly 70% of plastic in the oceans cannot be accounted for.
The Scope of Plastic Pollution
Plastic pollution in the oceans has been a growing concern, with an estimated 4.8 to 12.7 million tons of plastic waste entering marine environments annually. Southeast Asia, in particular, is a major contributor, producing nearly 10 million tons of plastic waste each year—roughly a third of the world’s total. This pollution poses a significant threat to marine ecosystems, breaking down into microplastics that are difficult to detect and harmful to marine life.
To better understand the impact of microplastics on local coral reefs, researchers from Kyushu University in Japan and Chulalongkorn University in Thailand joined forces. The two institutions established the Center for Ocean Plastic Studies in 2022, led by Professor Atsuhiko Isobe. This collaboration aimed to investigate how microplastics affect coral ecosystems in the Gulf of Thailand, particularly around Si Chang Island, an area known for its coral reef flats.
Coral as a 'Sink' for Microplastics
Coral is composed of three main anatomical parts: surface mucus, tissue, and skeleton. In this study, researchers developed a protocol to isolate microplastics from each of these layers. They collected and analyzed 27 coral samples from four different species, uncovering 174 microplastic particles ranging from 101 to 200 μm in size—about the width of a human hair. The microplastics were distributed across the coral’s anatomy, with 38% found in surface mucus, 25% in tissue, and 37% in the skeleton.
Notably, the study revealed that coral might act as a 'sink' for microplastics, absorbing and storing plastic waste from the surrounding water, much like trees sequester carbon dioxide from the atmosphere. This discovery offers a potential explanation for the 'missing plastic problem.' Coral skeletons, which can last for hundreds of years, may preserve microplastics long after the coral dies, offering a potential clue to where much of the ocean’s plastic has gone.
Types of Microplastics Found
The microplastics identified in the coral samples primarily consisted of nylon, polyacetylene, and polyethylene terephthalate (PET). These three materials accounted for a significant portion of the detected particles, with nylon making up 20.11%, polyacetylene 14.37%, and PET 9.77%. These substances are commonly used in manufacturing and everyday products, underscoring the pervasive nature of plastic pollution.
Implications and Future Research
While this study provides groundbreaking evidence that corals could be acting as reservoirs for microplastics, further research is needed to fully understand the implications of this discovery. The long-term effects of microplastic accumulation on coral health and the broader marine ecosystem remain unclear.
Assistant Professor Suppakarn Jandang from Kyushu University, the lead author of the study, emphasizes the need for global research: "The corals we studied are found all around the world. To get a more comprehensive understanding, we must conduct further studies across various coral species in different regions." Additionally, the team plans to investigate how microplastics may affect the health of coral reefs and their ability to support marine biodiversity.
The findings from this research represent a significant step toward addressing the mystery of missing oceanic plastics and provide a new perspective on how microplastics may be impacting marine ecosystems. However, much work remains to fully comprehend the scope of this pollution and its long-term consequences for our planet’s oceans.
As humanity continues to grapple with the consequences of plastic pollution, this study highlights the complex ways in which our waste interacts with marine environments. The discovery that coral skeletons can trap and store microplastics offers new insights into both the 'missing plastic problem' and the role that coral reefs play in marine ecosystems. Understanding the full impact of these findings will require further research, but they point to the critical need for global action to mitigate plastic pollution and protect our oceans.