A global understanding of major processes and mechanisms affecting the dynamics of mercury in the atmosphere and interfaces with other ecosystem compartments, particularly biotic, is crucial for setting management and monitoring strategies for mercury at local and global levels. Integrated and updated assessments, based on reliable and comparable monitoring data in abiotic and biotic media, from governments, international networks, and other sources, are essential for improving the global understanding of the movement of mercury through ecosystems and for predicting spatial and temporal trends.