In a groundbreaking study published in Microplastics & Nanoplastics, researchers have unveiled compelling new evidence about the behavior and fate of microplastics in the deep ocean. The international team led by Pereira, J.M., Menezes, G.M., and Porter, A. conducted an unprecedented year-long investigation focused on the sinking flux of microplastics at a remote deep-sea seamount in the North Atlantic. This pioneering flux study delivers crucial insights into the vertical transport mechanisms of plastic pollutants, revealing not just their presence but also their dynamic interactions within deep-sea ecosystems.
Microplastics—plastic particles smaller than five millimeters—have been widely detected in marine environments around the globe. Yet, their distribution and fate, especially in abyssal zones of the ocean, have remained elusive. This study successfully deployed sediment traps to capture sinking material, including microplastics, at varying depths across the flanks of the seamount. By collecting data over the span of an entire year, the researchers captured seasonal and episodic variations in microplastic flux, unraveling patterns that challenge previous assumptions concerning plastic particle degradation and sedimentation in oceanic depths.
The researchers’ data reveal a consistent, measurable flux of microplastic particles that sink through the water column, accumulating on the seamount’s slopes. This long-term monitoring approach allowed the team to observe not only immediate inputs but also temporal shifts likely driven by regional oceanographic processes, such as changes in current velocity, biological activity, and particulate organic carbon export. The findings suggest that microplastic pollution is not only surface-bound but is transported actively to remote deep-sea habitats, posing potential impacts on benthic communities and biogeochemical cycles.
Importantly, the study characterizes the composition and size distribution of the sinking plastics, highlighting a predominance of fibers and fragments derived from common consumer products and fishing materials. Through microscopic and spectroscopic techniques, the research identifies the polymer types, demonstrating that polyethylene and polypropylene dominate the samples. These polymers are known for their buoyant properties, yet their downward flux points to aggregation with sinking biogenic particles or biofouling processes that enhance their density, facilitating their transfer from surface waters to the deep seafloor.
This research advances understanding of microplastic sinking behavior by integrating long-term sediment trap data with oceanographic variables. The authors illustrate that particle fluxes are episodic and influenced by biological seasons, with peak microplastic deposition corresponding to periods of elevated primary productivity and subsequent marine snow production. Marine snow—the organic detritus that sinks from surface waters—appears to serve as an essential vector for microplastic transport, binding plastics and accelerating their descent through the water column.
Moreover, the investigation at the seamount setting underscores the ecological ramifications of plastic pollution beyond coastal zones and shelf sediments. Seamounts, often biodiversity hotspots harboring unique benthic communities, may act as sinks and reservoirs for anthropogenic debris. The accumulation of plastics in these fragile habitats raises urgent concerns about ingestion by deep-sea organisms, potential bioaccumulation, and the disruption of microbial and faunal communities responsible for carbon cycling and nutrient regeneration in the deep ocean.
The researchers also discuss the implications of their findings in the context of marine plastic budgets. For years, the ocean’s sinking pathways remained under-characterized, contributing to the so-called “missing plastic” problem—whereby calculated plastic inputs and observed surface concentrations did not align. This study helps fill a critical gap by quantifying the vertical downward flux to abyssal depths, proving that microplastics are indeed incorporated into deep-sea sedimentary processes, albeit with complex temporal variability.
To refine the accuracy of their measurements, the team employed rigorous contamination controls and utilized advanced polymer identification techniques, including Fourier-transform infrared (FTIR) spectroscopy and Raman microscopy. These analytical tools confirmed the chemical fingerprint of microplastics, distinguishing them from natural particulates. The methodology sets a new standard for in situ monitoring of microplastic fluxes, paving the way for expanded global observatories focused on deep ocean plastic pollution.
Crucially, the data from this seamount study divulge that microplastic flux is seasonally driven but exhibits surprising persistence even during less productive months. Such persistence implies that microplastic particles remain suspended and continue descending independently of biological cycles, possibly due to physical oceanographic dynamics such as mesoscale eddies and vertical mixing. This insight challenges simplistic models of microplastic transport and calls for integrated oceanographic research coupling plastics with physical and biological ocean processes.
The authors further speculate on the potential feedback mechanisms in the ocean carbon cycle influenced by plastic particles acting as vectors of microbial communities. There is mounting evidence that plastics provide novel substrates for microbial colonization, altering decomposition and biogeochemical pathways. At the scale of deep seamount ecosystems, such alterations could reverberate across trophic layers, emphasizing the need for interdisciplinary studies merging marine ecology, chemistry, and pollution science.
From a broader environmental perspective, this landmark research warns that solving plastic pollution demands attention to its hidden pathways, especially the long-term transport to remote, deep-sea environments vulnerable to anthropogenic disturbances. Until now, policy and cleanup efforts have largely focused on coastal and surface ocean plastics, yet the deep ocean represents a vast, under-studied repository that accumulates plastic debris beyond immediate human visibility. This study’s revelations beckon a redefinition of marine pollution mitigation strategies, incorporating deep ocean considerations.
These findings also pose challenges for ongoing environmental impact assessments and conservation planning. The sediments and biota at seamounts often serve as reference points for pristine oceanic conditions; however, the confirmed presence and continuous influx of plastics call into question baseline assumptions used in deep-sea ecosystem health assessments. Recognizing microplastic contamination as an emerging stressor is fundamental for future monitoring and management of marine protected areas.
The study’s year-long experimental design exemplifies the importance of temporal resolution in environmental monitoring. Many previous efforts relied on snapshot sampling that failed to capture dynamic fluxes. By contrast, this continuous flux measurement approach provides a nuanced view of pollutant behavior and establishes essential time series data that can inform predictive models and global marine plastic inventories with greater confidence.
In conclusion, Pereira and colleagues have made a significant leap forward in tracing the journey of microplastics from surface waters through the water column to the ocean’s depths. Their work exposes the previously invisible connections between plastic pollution and deep-sea ecosystems, exposing potential vulnerabilities and stressing the urgency of multidisciplinary investigations. Deep-sea plastic pollution is not a distant problem relegated to the future; it is an active, ongoing process reshaping marine environments in profound ways.
As science pushes the boundaries of understanding, this study stands as a clarion call to researchers, policymakers, and the public alike: addressing microplastic pollution requires a paradigm shift that includes the vast, dark expanses of the deep ocean. Only through such holistic perspectives can meaningful solutions be developed to protect the health and sustainability of our planet’s oceans.
Subject of Research: Microplastic sinking flux at a deep-sea seamount in the North Atlantic, with implications for transport mechanisms and ecological impact.
Article Title: Sinking microplastics at a deep-sea seamount in the North Atlantic: a year-long flux study.
Article References:
Pereira, J.M., Menezes, G.M., Porter, A. et al. Sinking microplastics at a deep-sea seamount in the North Atlantic: a year-long flux study. Micropl.&Nanopl. 5, 37 (2025). https://doi.org/10.1186/s43591-025-00140-x
Image Credits: AI Generated
