The presence of harmful plastic in the seas and in the organisms that inhabit them has already been detected for years. The damage that this material causes to life seems irreversible, and at times distant. But a recent investigation has just found that several species of marine worms and in the sediments of the waters of the Colombian Caribbean and Pacific contain microplastic particles.
The research was carried out in two ecosystems with very different dynamics: Buenaventura Bay, where rivers such as the Dagua and the Anchicaya flow, and the Gulf of Salamanca, a Caribbean zone close to cities, ports, and tourist activities. The results show that factors such as proximity to cities, tourism, and port activity influence the amount of microplastics that reach the sea, which puts the focus on waste management in coastal areas.
The research was led by students from the National University, Alishon Yuliana Estrada Stabilito (Biology), Karen Yicelth Morales Duarte (Biological Engineering), and Carlos David Rodriguez Amaranto (Cultural and Communicative Management). They collected 24 samples from the seabed at different times of the year and, in the laboratory, separated the microplastics from the sediment using saline solutions, observed them under the microscope, and classified them according to their shape, color, and size.
They also analyzed 231 organisms collected from the seabed—mainly worms, but also mollusks and crustaceans—to determine whether they had ingested these particles, directly examining the contents of their digestive system, reported the UNAL News Agency.
The results show that the Caribbean presents a higher load of microplastics, with averages close to 296 particles per kilogram of sediment, compared to 165 in the Colombian Pacific. “Most of these residues were fibers, mainly blue and red, less than 2 mm, associated with the wear of synthetic clothing, fishing nets, and other everyday plastics,” Rodriguez said, quoted by the Agency.
Microplastics are already in organisms
The study also established that the finer soils of the seabed—such as those that look like mud or sludge—retain more invisible plastic debris than coarse ones, because their small particles trap them more easily. One of the most relevant findings is that 22% of the organisms analyzed in the Caribbean and 3% in the Pacific had microplastics inside them.
The most affected were marine worms known as polychaetes, which live buried and feed on sediment, so they end up ingesting these particles along with their food. “We found that these organisms, due to the way they feed, are especially sensitive to contamination by this type of material, which makes them key indicators of the state of the ecosystem,” Morales said.
Tiny plastic fragments were also detected to a lesser extent in mollusks and other invertebrates, which indicates that this contamination is not isolated, but is beginning to move among different species of the marine ecosystem.
Although the levels found in Colombia are lower than in highly urbanized areas such as Tokyo Bay, where the ingestion of these particles reaches 90%, the study by the UNAL La Paz campus shows that the problem is already present in the country’s marine ecosystems.
In the Colombian Caribbean, an ingestion rate of 22% was recorded in organisms such as worms, mollusks, and small crustaceans, while in the Pacific it was 3%, which shows differences between regions but confirms that this contamination is already circulating on both coasts.
“These microplastics not only affect the organisms that ingest them, altering their feeding and development, but they can also carry toxic substances and pass from one species to another, with possible effects throughout the food chain,” the student Estrada stated.”**