Costa Mar Reef Survey Documents Plastic Accumulation in Deep Channels

The survey, conducted over six weeks between late March and early May, sampled forty-three sites across Costa Mar's marine territory. Microplastics concentrations in sediment cores from the deep channels—the underwater passages that run between the main reef systems—averaged 2.8 milligrams per kilogram of sediment, compared to 2.1 milligrams per kilogram in the 2025 spring survey. The increase is modest in absolute terms but consistent with a longer trend that has begun to concern the network's scientific leadership.

The deep channels carry nutrient-rich currents that feed the reef's biodiversity, but they also accumulate drifting debris from the open ocean. Currents from Oriente Moderno's shipping lanes—some two hundred kilometers to the northeast—carry a steady load of microplastics that eventually settle in Costa Mar's waters. The Reef Monitoring Network has documented this transit pattern in previous years, but the spring 2026 survey found the concentrations higher than models had predicted.

The network's director, Dr. Silvio Montoya, said in an interview that the findings warrant expanded cleanup operations in the deep channels, a task that requires specialized equipment and expertise that Costa Mar has only recently begun to develop. The regional government has committed additional funding to the effort, but the scale of the problem may exceed the region's current capacity to address it alone.