Occurrence, turnover and carbon sequestration potential of phytoliths in terrestrial ecosystems

Carbon sequestered in phytoliths, the silicified features of plants, may accumulate in soils and sediments for several hundreds to thousands of years depending mainly on the morphology and chemical composition of phytoliths and environmental conditions. Phytolith carbon sequestration is thought to be one of the key biogeochemical carbon sequestration mechanisms. This review summarizes the current state of understanding of occurrence, turnover and carbon sequestration potential of phytoliths in terrestrial ecosystems. The accumulation rate of phytoliths in soils is controlled not only by plant litter inputs but also by geochemical stability and turnover of phytoliths. Most of the organic carbon in phytoliths is from photosynthesis of atmospheric carbon dioxide (CO2) during formation of phytoliths. Phytolith carbon sequestration in terrestrial ecosystems is a promising biogeochemical carbon sequestration mechanism and may contribute to the mitigation of global climate warming. Further questions such as the turnover of phytoliths with different properties and under different environmental conditions, the relative contribution of different ecosystems to the global terrestrial phytolith carbon sequestration, and the cost and potential of each management measure to enhance phytolith carbon sequestration should be investigated.