中国喀斯特关键带岩石风化碳汇评估及其生态服务功能

喀斯特地区的岩石风化固碳被认为是全球遗漏碳汇之一,中国喀斯特地区的分布面积达344万km²,目前对其岩溶碳汇缺乏精确、系统的评估,对碳汇产生的机制仍存在争议。本文通过对喀斯特地区碳汇研究的回顾,详细介绍了适用于喀斯特地区固碳速率的估算方法,并对喀斯特地区的岩石风化碳汇进行再评估,然后将地球关键带科学概念引入喀斯特生态系统,阐述喀斯特关键带碳汇研究对生态系统服务和功能的意义。研究结果表明,中国喀斯特地区每年因岩溶作用产生的碳汇为4.74 Tg C yr^-1,未来中国需要加强岩石—土壤—水体—生物—大气复杂交互系统的基础数据收集,以明确各界面碳通量,对喀斯特关键带碳汇进行多尺度、多方法、全方位联合评估,在改善喀斯特生态系统功能、科学管理区域和国家碳收支及全球变化研究等方面为政府和学者提供参考。

Rock-weathering-related carbon sinks and associated ecosystem service functions in the karst critical zone in China

The global karst area is about 2.2×10⁷ km², wherein China reaches up to 3.44×10⁶ km², occupying more than one third of the global karst area. The previous studies have showed that carbon (C) sequestration rate by chemical weathering in Chinese karst zone range from 5 Tg C yr^-1 to 18 Tg C yr^-1, which are considered as one of important "residual land sink" in global change research. In order to accurately estimate the C sequestration rate in karst area, we put forward the concept of Earth Critical Zone (CZ) for karst ecological system. In this study, we comprehensively understand the C cycle in karst CZ, introduce the estimation of the methods on karst CZ, and then re-evaluate the C sequestration rate in the karst CZ. At last, we systematically discuss the uncertainty of the C sinks in karst CZ. The results show that the rock-weathering-related C sink rate in Chinese karst CZ is about 4.74 Tg C yr^-1. In addition, we elaborate the significance of C sequestration to ecological system service in karst CZ, strive to to strengthen the C monitor at rock-soil-water-biological-atmosphere continuum level in the future, and then use different methods to estimate and evaluate C cycle at multi-scale in karst CZ.