Anthropogenic pollutants’ threats to deep-sea ecosystems: Research challenges and technological frontiers

Prior to the full recognition of its complexity, deep-sea environments have already been affected by human activities.Moving beyond descriptive and observation-bound monitoring, this Comment proposes an integrative framework that synthesizes pollutant dynamics with deep-sea hydro-biogeochemistry, extreme-environment ecotoxicology, and advanced in situ ecological monitoring.Transformative advances in integrated observation and simulation technologies will shift deep-sea pollution research from descriptive assessment to proactive forecasting, offering the critical evidence base required to conserve the ocean's largest and most vulnerable realm.The deep sea, encompassing ocean depths below 200 m, represents more than 95% of the ocean's volume and hosts a spectacular variety of ecosystems, including continental shelves, abyssal plains, seamounts, cold seeps, hydrothermal vents, and hadal trenches.Despite its remoteness, anthropogenic pollutants have permeated even the most inaccessible regions.Plastics, persistent organic pollutants (POPs), heavy metals, per/polyfluoroalkyl substances (PFASs), flame retardants, and antibiotic resistance genes (ARGs) are frequently detected in deepsea water and sediments [1,2].Particularly notable is the significant presence of pollutants in hadal trenches (e.g., chlorinated paraffin concentrations up to 14,000 ng/g dw at depths > 10,000 m [3]), highlighting the pervasive impacts of human activity.However, the deep sea remains one of the least studied environments, where technological and methodological challenges pose a major barrier to understanding the pollutant fates, toxicological mechanisms, and overall risks to deep-sea ecosystems.