Reactive Oxygen Species Trigger Rapid Natural Purification of Soils and Water in Wetlands

Wetlands, often referred to as the “Earth’s kidneys”, are essential ecosystems that filter pollutants and regulate biogeochemical processes. However, the mechanisms underlying their rapid self-purification are still in their infancy and lack deep understanding. Here, we propose that reactive oxygen species (ROS) constitute an intrinsic oxidative network that drives accelerated pollutant transformation in wetlands. We summarize that ROS are generated through coupled photochemical and redox-driven processes and are highly concentrated at environmental interfaces, including soil–water, fluctuating redox boundaries, and rhizosphere. These interfaces function as reactive hotspots where the colocalization of organic matter, minerals, oxygen, and microorganisms amplifies ROS production far beyond bulk water levels. Interfacial ROS enrichment can shorten pollutant half-lives and alter oxidative pathways, as illustrated by a representative pesticide. Advances in in situ and real-time ROS imaging have enabled direct observation of these microscale hotspots, providing new insights into the spatiotemporal dynamics of ROS-driven processes. We further identify key challenges in resolving and monitoring fine-scale ROS dynamics, interfacial electron transfer, and scaling microscale processes to ecosystem-level functions. This perspective reframes wetlands as interface-driven oxidative systems, highlighting ROS-mediated processes as significant regulators of pollutant transformation and providing a conceptual basis for developing wetlands as controllable biogeochemical reactors.