Microplastics Discovered 2.4 Kilometres Below Indonesian Ocean Surface, Here Are the Dangers
Jakarta – Recent research has discovered that microplastics have reached extremely deep ocean depths in Indonesian waters. These tiny plastic particles have been detected at approximately 2,450 metres below the ocean surface and have the potential to enter the food chain and ultimately be consumed by humans.
The findings were revealed in a study published in the international scientific journal Marine Pollution Bulletin. The research was conducted by Senior Researcher Corry Yanti Manullang from the Deep Sea Research Centre of the National Research and Innovation Agency (BRIN), together with a research team from Indonesia, Malaysia, the United States, and China.
The research was conducted along the Indonesian Throughflow (Arlindo) route, an important ocean current system that connects the Pacific and Indian Oceans through Indonesian waters. This current flows through several major straits including the Makassar Strait, Alas Strait, and Lombok Strait.
“Arlindo connects two large oceans, the Pacific and Indian. Besides carrying water masses, salt, and nutrients, this current also has the potential to carry small particles such as microplastics,” said Corry in an official BRIN statement.
Previous research on Arlindo has predominantly focused on physical ocean conditions such as temperature, salinity, and current patterns. However, the distribution of microplastics throughout the water column and deep ocean remains relatively unexplored.
The research was conducted through an oceanographic expedition from January to April 2021 as part of the international collaborative TRIUMPH programme. Water samples were collected at 11 observation points from the Makassar Strait to the Lombok Strait.
The research team collected 92 seawater samples from various depths, ranging from approximately 5 metres to 2,450 metres using a rosette sampler connected to a CTD (Conductivity, Temperature, Depth) system.
From a total of 872 litres of seawater analysed, researchers identified 924 microplastic particles with an average concentration of approximately 1.062 particles per litre. Microplastics were found at all research locations, including at depths exceeding two kilometres below the ocean surface.
The analysis revealed that over 90% of microplastics are in fibre form, which typically originates from synthetic textile materials.
“The clothes we wear can also produce microplastics. When washed, small fibres from synthetic fabrics can be released and eventually enter the water system,” explained Corry.
In addition to fibres, researchers also identified several types of plastic polymers including polyester, polypropylene, and polyurethane, which are widely used in textile products, packaging, and industrial materials. These findings indicate that the deep ocean has the potential to become a site of microplastic accumulation as ocean currents can transport plastic particles throughout various water layers.
Entering the Food Chain
Beyond researching the distribution of microplastics in seawater, the research team also examined the possibility of these particles entering the marine food chain. In another study published in the journal Sains Malaysiana, researchers discovered that microplastics had entered the bodies of small zooplankton organisms called copepods along the Arlindo route.
Copepods are extremely abundant organisms in the ocean and serve as an important food source for many types of fish. From approximately 6,000 copepod individuals analysed, researchers found 133 microplastic particles within these organisms. The average consumption rate was recorded at approximately 0.022 particles per individual, equivalent to one plastic particle for every 45 copepods.
“Copepods cannot distinguish between natural food and plastic particles. Anything that passes in front of them will be caught and consumed,” said Corry.
The presence of microplastics in copepod bodies is concerning because these organisms are a primary food source for small fish. Small fish are subsequently consumed by larger fish, which are eventually consumed by humans.
“This means microplastics have the potential to transfer throughout the food chain and reach humans,” she noted.
Corry added that research on microplastics in Indonesian seas still needs to be expanded, particularly in deep ocean regions. Approximately 70% of Indonesian maritime territory has depths exceeding 200 metres, so deep ocean ecosystems remain relatively understudied.
She hopes these findings will serve as a foundation for further research regarding microplastic movement in the deep ocean and its effects on marine ecosystems and human health.