植硅体碳与陆地生态系统碳循环:机遇和挑战

Phytolith-Occluded Carbon and Terrestrial Ecosystem Carbon Cycle:Opportunities and Challenges

植硅体在形成过程中能够包裹植物有机碳,是已被证明的一种非常有潜力的大气CO_(2)封存方式,对于增加陆地生态系统碳汇和延缓温室气体效应带来的全球变暖具有重要意义,因此受到了学术界的广泛关注。简要回顾了植硅体碳的研究历史和现状,并着重从植硅体碳长期变化入手,探讨了植硅体碳与陆地生态系统碳汇存在的问题与挑战,以及近来有关植硅体碳存在被严重高估的论点。同时指出为了更加准确地估算植硅体碳汇,应充分考虑植硅体包裹碳能力的差异、植硅体碳来源、植硅体稳定性、土壤中植硅体碳含量衰减速率以及植硅体提取方法等在植硅体碳的长期变化中的作用,进一步提高植硅体碳在陆地碳汇研究中的地位与重要性。

A small amount of organic carbon,referred to as phytolith-occluded carbon(PhytOC),is occluded during phytolith formation.This carbon fraction has been demonstrated to be an important form of carbon sequestration.Thus,it has drawn particular attention from many researchers in the study of the terrestrial carbon cycle because it is of great significance for increasing terrestrial ecosystem carbon sinks and delaying global warming caused by the greenhouse gas effect.First,we briefly reviewed the research history and current status of PhytOC.Then,focusing on the long-term changes in PhytOC,we discussed the questions and challenges of PhytOC and terrestrial ecosystem carbon sinks as well as the recent argument that carbon sequestration by PhytOC in terrestrial ecosystems was highly overestimated.However,to more accurately estimate the phytolith carbon sink,some factors should be considered regarding long-term changes in PhytOC,such as different carbonoccluded abilities,carbon source,and stability of phytolith,decay rate of PhytOC in soil,and the impact of different phytolith extraction methods on PhytOC.As a result,the status and importance of PhytOC in studying terrestrial carbon sinks would be enhanced.