Phytolith carbon sequestration in global terrestrial biomes

• Published in: The Science of the total environment Vol. 603-604; pp. 502 - 509
• Main Authors: Song, Zhaoliang, Liu, Hongyan, Strömberg, Caroline A.E., Yang, Xiaomin, Zhang, Xiaodong
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.12.2017
• Subjects: Africa; Agriculture; Asia; Bacillariophyceae; bamboos; Biogeochemical carbon sequestration; Carbon; Carbon Sequestration; Carbon sink; cropland; Crops, Agricultural - metabolism; ecosystems; Forests; Grassland; grasslands; Models, Theoretical; Phytolith-occluded carbon (PhytOC); phytoliths; Plants - metabolism; reforestation; sediments; silica; silicates; Silicon; South America; Terrestrial biomes; weathering; South America; Asia; Africa; Biogeochemical carbon sequestration; Carbon sink; Silicon; Phytolith-occluded carbon (PhytOC); Terrestrial biomes
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2017.06.107

Terrestrial biogeochemical carbon (C) sequestration is coupled with the biogeochemical silicon (Si) cycle through mechanisms such as phytolith C sequestration, but the size and distribution of the phytolith C sink remain unclear. Here, we estimate phytolith C sequestration in global terrestrial biomes. We used biome data including productivity, phytolith and silica contents, and the phytolith stability factor to preliminarily determine the size and distribution of the phytolith C sink in global terrestrial biomes. Total phytolith C sequestration in global terrestrial biomes is 156.7±91.6TgCO2yr−1. Grassland (40%), cropland (35%), and forest (20%) biomes are the dominant producers of phytolith-based carbon; geographically, the main contributors are Asia (31%), Africa (24%), and South America (17%). Practices such as bamboo afforestation/reforestation and grassland recovery for economic and ecological purposes could theoretically double the above phytolith C sink. The potential terrestrial phytolith C sequestration during 2000–2099 under such practices would be 15.7–40.5PgCO2, equivalent in magnitude to the C sequestration of oceanic diatoms in sediments and through silicate weathering. Phytolith C sequestration contributes vitally to the global C cycle, hence, it is essential to incorporate plant-soil silica cycling in biogeochemical C cycle models. [Display omitted] •Carbon occluded within phytolith is a stable bio-geochemical C sink mechanism.•Phytolith C sequestration in global terrestrial biomes is 156.7 ± 91.6 Tg CO2 yr–1.•The main contributors are Asia (31%), Africa (24%), and South America (17%).•Appropriate practices could theoretically double the phytolith C sink in global terrestrial biomes.