Karst areas with carbonate bedrock comprise approximately 20 % of ice-free land on earth and provide water resources for about 25% of the Earth’s population, as well as under-pinning substantial food production. The critical zone extends from the base of the groundwater system to the top of the vegetation canopy, and comprises a complex system of coupled chemical, biological, physical and geological processes, which together support life at the Earth’s surface. Human impacts including intensive land use, contamination, and consequences of climate change have brought severe changes to the functioning of the critical zone. Owing to the inherent vulnerability of many karst ecosystems to disturbance, these are often particularly severe in karst areas. This has resulted in many emerging challenges for soil science, hydrology and related disciplines to understand how land-management practices impact biogeochemical cycles, and consequently the ability of the karst critical zone to provide future ecosystem services. The special characteristics of the critical zone in karst areas include heterogeneity of aquifer properties, thin soil profiles with a direct soil-rock contact, and unique weathering processes. This results in challenges to biogeochemical cycles studies in karst systems, requiring novel techniques and different approaches to non-karst areas.

Critical zone science is necessarily interdisciplinary. This session strongly encourages work drawing on a range of disciplines that will further our understanding of biogeochemical cycling in the karst critical zone. This will provide the knowledge base on which future management of karst areas is based, in order to secure their ability to provide ecosystem services. Work from all relevant disciplines is encouraged, including soil science, water quality, geology, karst hydrology, ecology, agronomy, and ecosystem services in karstic systems, which may draw from both long-term monitoring and high resolution study of occasional or extreme events. Work may include modelling, experimentation, reviews or a combination of the three.