Impact of Land-Use and Land-Cover change on the carbon sink produced by karst processes:A review

ZENG Si-bo; JIANG Yong-jun

doi:10.11932/karst20160204

Abstract：Based on a new conceptual model of carbon cycle induced by the weathering carbonate rocks,the study of karst process is now having a new direction for researchers to find stable carbon sink in terrestrial carbon cycle ecosystem.The carbon cycle produced by the weathering of carbonate rocks used to be consid-ered as an unchanged carbon sink since pre-industrial times in global carbon model.However,a synthesis of recently published work reveals that Land Use/Cover Change (LUCC)due to human activities have altered these carbon fluxes.This paper is intended to review the observations concerning carbonate the response of rock weathering to LUCC,as well as a thorough analysis for their mechanisms.Recent findings show that the impact of LUCC on carbon cycle in karst process is complicated and this cycle is dependent on three as-pects,i.e.soil pCO 2 ,runoff fluctuation and the involvement of some inorganic acids,which may interact each other and control the magnitudes,variations of carbonate rock weathering under various LUCC.The effect of the first two aspects may present negative correlation,and the mechanisms of inorganic acids have different effects in the new model.Meanwhile,previous studies ignored the autochthonous organic carbon (AOC)produced in surface stream ecosystem which has great carbon sequestration capacity.The response process and mechanism to LUCC is a new direction of karst carbon cycle study.However,because of the complexity and diversity of the carbonate rock weathering under LUCC,it is difficult to determine the rela-tionship between DIC and AOC variations in various environmental conditions caused by LUCC.Therefore, how to probe into the mechanism of carbonate rock weathering and to establish a LUCC regulating strategy are important directions of future karst carbon cycle research.