Mangrove leaves have been recognized as essential sinks for coastal microplastics (MPs). However, the temporal dynamics of MPs intercepted by these leaves are still not well understood. In this study, we investigated the interception of MPs by submerged and non-submerged mangrove leaves over time, along with the potential driving factors. The abundance and characteristics of MPs captured by mangrove leaves exhibited dynamic fluctuations, with the coefficient of variation (CV) for submerged leaves (CV = 0.604; ranging from 1.76 n/g to 15.45 n/g) being nearly double that of non-submerged leaves (CV = 0.377; ranging from 0.74 n/g to 3.28 n/g). Furthermore, partial least squares path model (PLS-PM) analysis indicated a negative correlation between the abundance of MPs on submerged mangrove leaves and hydrodynamic factors, such as current velocity and tidal range. Notably, secreted salt emerged as a significant driver of MPs interception by mangrove leaves. The findings underscore the dynamic fluctuations in the interception of MPs by mangrove leaves and highlight the roles of hydrodynamic factors and secreted salts. Overall, this research elucidates the critical buffering role of mangrove leaves in intercepting MPs, contributing to a better understanding of microplastic pollution and its management within mangrove ecosystems.

Microplastics; Mangrove leaves; Secreted salts; Hydrodynamic factors