岩溶洞穴滴水环境监测研究进展

通过对已有成果的疏理总结,前人的洞穴滴水环境监测研究取得了以下几个方面的主要认识:(1)滴水的氢氧同位素组成虽然基本反映了大气降水的同位素构成,但由于洞穴上覆岩层厚度及裂隙的差异等,导致滴水对降水时间响应不同,滴水氢氧同位素变化存在多样性.(2)滴水化学组成主要受到水—土—岩—气之间相互作用影响,其中的溶解无机碳同位素及有机酸等还受到上覆植被类型以及密度的影响.(3)洞穴物理环境条件是决定洞穴滴水—沉积物中氧碳稳定同位素能否达到平衡分馏的重要因素.(4)由于滴水化学组成指示气候环境变化仍存在多解性和不确定性,需要将洞穴监测研究从洞穴内部扩大到洞穴上覆土壤、植被等中间过程,建立立体监测体系.(5)目前的洞穴环境监测仍缺乏不同自然条件下的综合对比研究,有待今后开展和加强.

Research progress of monitoring for dripping water environment in karst caves

Based on the study of the former achievement, it is concluded that the research process of monitoring for dripping water environment in karst caves mainly includes the following 5 items. （1） Although the oxyhydrogen isotope component in dripping water basically represents the isotope components in the atmospheric precipitation, variation of the oxyhydrogen isotope in dipping water is diversity, due to the differences in the thickness and fissures of the overlying rocks above the cave, that leading to the differences in time response between the dripping water and the rainfall. （2） The chemical component of the dripping water mainly affected by the interaction among water, soil, bedrock and gas, and the dissolved inorganic carbon and organic acid is also affected by the vegetation form and density. （3） The physical condition of caves is an important factor that deciding whether the oxygen and carbon stable isotopes in the speleothem by dripping water can reach the state of equilibrium fractionation or not. （4） Because there are multiple solution and uncertainty in the indicating climatic change by components of the dripping water, the cave monitor should be extended to the overlying soil and vegetation outside of the cave to form a three-dimensional monitor system. （5） Monitoring for karst cave environments still needs synthetic comparison study under different natural conditions.