Hotspot regions of reactive oxygen species production and their environmental impacts in periodically flooded soil environments: a review

The Intertidal Soil (ITS) zone is a unique and critical component of Earth's ecosystems, characterized by a high diversity of biological species and frequent exchanges of matter and energy. Reactive Oxygen Species (ROS), naturally occurring reactive molecules, play vital roles in chemical cycling. They are also crucial in environmental management and remediation, pollutant degradation, and ecosystem health. Recent research has revealed that substantial ROS production can occur in dark conditions, driven primarily by redox cycles. This finding is particularly significant for the ITS zone, where redox cycles are prevalent. This review first analyzes the shifting research interests in ROS over the past decade and the emerging trends in ITS zone studies, providing a reference for future research. Additionally, it identified key hotspots for ROS generation within the ITS zone and analyzed the mechanisms of ROS production from both biological and abiotic perspectives, aiming to deepen the understanding of material transformation in ITS settings. Furthermore, this review comprehensively summarizes the potential impacts of ROS on biological activity, mineral transformation, organic pollutant degradation, heavy metal (and metalloid) mobility, and microplastic degradation in the ITS zone. This synthesis enhances researchers' understanding of the roles ROS play in these processes. Lastly, current methodologies for detecting and quenching ROS were compiled, along with associated measurement precautions, offering reliable references for subsequent studies on ROS in the ITS zone. In summary, this review extensively covers the sources and sinks of ROS in the ITS zone and outlines current research directions with significant potential. The insights provided hold valuable implications for studying ITS zone biology, ecology, geology, and climate change.