Biogeochemical sequestration of carbon within phytoliths of wetland plants: A case study of Xixi wetland, China

As an important long-term terrestrial carbon sequestration mechanism, biogeochemical sequestration of carbon within phytoliths may play a significant role in the global carbon cycle and climate change. The aim of this study is to explore the potential of carbon bio-sequestration within phytoliths produced by wetland plants. The results show that the occluded carbon content of phytoliths in wetland plants ranges from 0.49% to 3.97%, with a CV (coefficient of variation) value of 810%. The data also indicate that the phytolith-occluded carbon (PhytOC) content of biomass for wetland plants depends not only on the phytolith content of biomass, but also the efficiency of carbon occlusion within phytoliths during plant growth in herb-dominated fens. The fluxes of carbon bio-sequestration within phytoliths of herb-dominated fen plants range from 0.003 to 0.077 t CO₂ equivalents t-e-CO₂ ha^?1 a^?1. In China, 0.04×10⁶ to 1.05×10⁶ t CO₂ equivalents per year may be sequestrated in phytoliths of herbaceous-dominated fen plants. Globally, taking a fen area of 1.48×10⁸ ha and the largest phytolith carbon biosequestration flux (0.077 t-e-CO₂ ha^?1 a^?1) for herb-dominated fen plants, about 1.14×10⁷ t CO₂ equivalents per year would have been sequestrated in phytoliths of fen plants. If other wetland plants have similar PhytOC production flux with herb-dominated fen plants (0.077 t-e-CO₂ ha^?1 a^?1), about 4.39×10⁷ t-e-CO₂ a^?1 may be sequestrated in the phytoliths of world wetland plants. The data indicate that the management of wetland ecosystems (e.g. selection of plant species) to maximize the production of PhytOC have the potential to bio-sequestrate considerable quantities of atmospheric CO₂.