Characteristics of Si Biogeochemical Cycle in Freshwater Riparian Wetlands: A Comprehensive Review

Abstract

Purpose of Review

The silicon (Si) biogeochemical cycle in ecosystems is tightly linked with other elemental cycles and plays a key role in addressing ecological challenges such as water quality deterioration, climate warming, and biodiversity reduction. As transitional zones between aquatic and terrestrial ecosystems, riparian wetlands possess unique eco-environmental characteristics that enable them to regulate the flow and forms of terrestrial Si into aquatic ecosystems. This paper systematically reviews the characteristics of the Si biogeochemical cycle in riparian wetlands, emphasizing the influence of environmental factors on Si transformation. Additionally, it highlights key knowledge gaps in the Si cycle within riparian wetlands that warrant further research.

Recent Findings

Si is considered “quasi-essential” for plant growth. During growth, plants not only assimilate CO₂ from the atmosphere but also convert dissolved Si into biogenic silicon (BSi). Enhancing the ability of plants to assimilate CO₂ through Si uptake is regarded as an effective approach to mitigating climate warming. BSi plays a dominant role in Si fluxes from terrestrial to aquatic ecosystems, with riparian wetlands serving as primary sites for BSi formation. The distinct hydrological characteristics of riparian wetlands have significant impacts on Si movement and transformation. Additionally, factors such as vegetation composition, soil physicochemical properties, and human activities further influence the Si cycle.

Summary

This review summarizes the characteristics of riparian wetlands, as well as the forms and distribution of Si within these ecosystems. It then emphasizes the biogeochemical processes of Si, the characteristics of Si cycle, and the factors that influence it. This review also identifies knowledge gaps and outlines priorities for future research.