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Article ? AI-assigned paper type based on the abstract. Classification may not be perfect — flag errors using the feedback button. Tier 2 ? Original research — experimental, observational, or case-control study. Direct primary evidence. Detection Methods Environmental Sources Marine & Wildlife Sign in to save

Structural biases in marine microplastics research: the underrepresentation of deep ocean and full water column studies

Environmental Research Letters 2026
Francisco Machin, J Hernández-Borges, E Fraile-Nuez, D Vega-Moreno

Summary

A systematic analysis of over 40,000 microplastic research papers published between 1980 and 2024 reveals that the field is heavily skewed toward studying beaches, coastlines, and surface waters, while deep ocean environments — despite likely being the largest long-term repository for microplastics — remain drastically understudied. Mitigation and adaptation research also lags far behind diagnostic studies. This structural bias in the literature means we may be systematically underestimating how much plastic accumulates in the deep sea and have limited strategies for addressing it.

Study Type Environmental

Abstract The distribution and fate of marine microplastics have become central concerns in ocean science, yet the literature remains strongly biased toward coastal and surface environments. This review presents a systematic analysis of over 40 000 peer-reviewed articles indexed in Scopus and Web of Science between 1980 and 2024, classified according to their disciplinary scope, marine environment, and climate-inspired framing (diagnosis, mitigation, adaptation). Our results reveal persistent structural imbalances: biology dominates thematically, beaches and coastlines dominate spatially, and diagnostic efforts far outnumber mitigation or adaptation studies. Crucially, the deep ocean—despite comprising the majority of marine volume and likely acting as a long-term reservoir for microplastics—remains severely underrepresented. Studies that include sampling below 1000 m are rare, and most lack specific geographic metadata. While the growth in microplastics literature is robust, its conceptual and spatial coverage remains narrow. We argue for a strategic expansion of research to include the full depth and breadth of the ocean, and for increased interdisciplinarity to reduce current uncertainties in global plastic budgets and support evidence-based mitigation efforts.

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