TEMPO. CCO, Jakarta - A joint international study has detected microplastics in Indonesian waters at depths of up to 2,450 meters, showing that plastic pollution has reached even the deep ocean.
The tiny particles, which measure less than five millimeters, could potentially enter the marine food chain and eventually be consumed by humans.
“In addition to transporting water mass, salt, and nutrients, ocean currents also have the potential to carry small particles such as microplastics,” said Corry Yanti Manullang, a researcher at the Center for Deep Sea Research of the National Research and Innovation Agency.
According to the agency’s website on Friday, March 6, 2026, the study involved researchers from Indonesia, Malaysia, the United States, and China.
The research focused on waters influenced by the Indonesian Throughflow, locally known as Arlindo, which connects the Pacific Ocean and the Indian Ocean through key straits including the Makassar Strait, Alas Strait, and Lombok Strait.
Microplastics Found in Deep Waters
The findings were published in the journal Marine Pollution Bulletin in a study titled Vertical Distribution of Microplastic Along the Main Gate of Indonesian Throughflow Pathways. Corry said the research is among the first to examine the vertical distribution of microplastics in deep waters along the Indonesian Throughflow route.
Previous studies on the current mainly focused on oceanographic factors such as temperature, salinity, and circulation. Meanwhile, most microplastic studies in Indonesian waters have concentrated on surface layers or coastal areas.
The research team collected 92 water column samples from 11 observation stations stretching from the Makassar Strait to the Lombok Strait. Samples were taken from depths ranging between 5 meters and 2,450 meters.
Water samples were obtained using a rosette sampler connected to a CTD (conductivity, temperature, depth) system, allowing researchers to collect water at precise depths. “Sample bottles are lowered into the sea and then closed at the targeted depth,” Corry explained.
From 872 liters of seawater analyzed, researchers identified 924 microplastic particles. On average, this equates to about 1.062 particles per liter. Microplastics were detected at every observation station, including at depths of more than two kilometers below the sea surface.
More than 90 percent of the particles were found in fiber form, typically originating from synthetic textile materials. “The clothes we wear can also produce microplastics. During washing, tiny fibers from synthetic fabrics can detach and eventually enter water systems,” Corry said.
Using Raman spectroscopy analysis, the team also identified several types of plastic polymers, including polyester, polypropylene, and polyurethane—materials commonly used in textiles, packaging, and industrial products.
The findings suggest that the deep ocean could act as a long-term accumulation site for plastic particles. According to Corry, strong currents in parts of the Indonesian Throughflow may transport microplastics across different water layers.
Microplastics Detected in Zooplankton
In a separate study examining the marine food chain, the research team found microplastics in zooplankton living in the same ocean current system.
Published in the journal Sains Malaysiana under the title Ingestion of Microplastics in the Planktonic Copepod from the Indonesian Throughflow Pathways, the study analyzed small zooplankton known as copepods.
Copepods are among the most abundant zooplankton in the ocean and serve as a key food source for many fish species. Researchers examined around 6,000 copepod specimens collected from several locations along the Indonesian Throughflow route.
“Copepods cannot distinguish between natural food and plastic particles. Whatever passes in front of them can be captured and consumed,” Corry said.
The study also found that larger copepods tended to contain more microplastics than smaller ones. Scientists warn that the presence of microplastics in these organisms is concerning because they form the base of the marine food web.
“Copepods are eaten by small fish, which are then eaten by larger fish. Eventually, these fish may be consumed by humans,” Corry said. “This means microplastics have the potential to move along the food chain to humans.”
Need for More Deep-Sea Research
Corry noted that research on microplastics in Indonesian waters, particularly in deep-sea ecosystems, remains limited. Around 70 percent of Indonesia’s marine territory has depths exceeding 200 meters, yet much of it has not been extensively studied.
“The discovery of microplastics at depths of more than two kilometers shows that plastic pollution is not only a coastal problem,” she said. “It has become an issue for the entire marine ecosystem.”
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