Phytolith Carbon Sequestration in Shrublands of North China

Abstract

Global warming mainly due to emissions of carbon dioxide (CO 2) and other greenhouse gases has initiated wide interest in the investigation of various land CO 2 sequestration mechanisms. As a long-term terrestrial carbon sequestration mechanism, phytolith carbon sequestration may play an important role in the global carbon cycle and climate change. This study investigated the distribution of phytoliths and phytolith-occluded carbon (PhytOC) in shrublands of North China to understand the potential of phytolith carbon sequestration within shrublands. The results indicated positive correlations between PhytOC content of biomass and phytolith content of biomass in the shrub layer, and between PhytOC content of biomass and carbon content of phytoliths in the herb layer of shrublands. The PhytOC production fluxes of five shrublands through shrub leaves and herb layers were 4.12–7.94 kg CO 2 ha−1 a−1 with an average of 5.95 kg CO 2 ha−1 a−1, and decreased in the following order: Ostryopsis davidiana-shrubland >Spiraea salicifolia-shrubland ≈Armeniaca sibirica-shrubland > Ziziphus jujuba-shrubland >Vitex negundo-shrubland. The mean rate of PhytOC production in temperate shrubland of North China was 0.45 ± 0.09 Tg CO 2 a−1. The data indicate that phytolith carbon sequestration in shrublands is a significant mechanism to mediate the increase of atmospheric CO 2. The potential of phytolith carbon sequestration in China’s shrublands may be further enhanced by adaptive management of shrublands, such as conservation of plant species with high PhytOC production flux.