School of Karst Science/School of Geography and Environmental Science, Guizhou Normal University, 550001 Guiyang, People's Republic of China; The State Key Laboratory Incubation Base for Karst Mountain Ecology Environment of Guizhou Province, 550001 Guiyang, People's Republic of China.
School of Karst Science/School of Geography and Environmental Science, Guizhou Normal University, 550001 Guiyang, People's Republic of China; The State Key Laboratory Incubation Base for Karst Mountain Ecology Environment of Guizhou Province, 550001 Guiyang, People's Republic of China.
Environ Res. 2024 Jan 1;240(Pt 1):117508. doi: 10.1016/j.envres.2023.117508. Epub 2023 Oct 26.
Sulfuric acid is involved in carbonate rock dissolution in karst areas and affects regional hydrogeochemical and carbon cycling processes. Sulfate sources and carbonate weathering at dripwater points of different hydrological types also differ significantly. Therefore, in this paper, three dripwater points (SQ2#, PB and MH6#) of different hydrological types in Dafeng Cave and Mahuang Cave were selected and systematically analyzed. The results show that: (1) ions in the cave dripwater mainly originated from rock weathering, and the water chemistry types were HCO·Ca-Mg and HCO-SO·Ca-Mg. (2) Sulfur and oxygen isotopes reveal that sulfate in the cave water of Shuanghe Cave mainly came from a mixture of soil sulfate and chemical fertilizers. (3) The Simmr model shows that the main sources of sulfate at each dripwater point were natural sources, such as soil sulfate and gypsum dissolution. The natural sources contributed more than 80% of the sulfate in the cave water and were less affected by anthropogenic activities. (4) Carbonate weathering by sulfuric acid (CSW) can accelerate rock weathering and the prior calcite precipitation effect, involving regional CO exchange through fissure pipes. The forward model results show that CSW reduced the karst carbon sinks at SQ2#, PB and MH6# by about 19.44%, 23.88% and 12.74%, respectively. Therefore, the impact cannot be ignored in assessing carbon source and sink processes in karst areas.
硫酸参与了岩溶地区碳酸盐岩的溶解过程，影响了区域水文地球化学和碳循环过程。不同水文类型的滴水点硫酸盐来源和碳酸盐风化也有显著差异。因此，本文选择了大峰洞和麻璜洞三种不同水文类型的三个滴水点（SQ2#、PB 和 MH6#）进行系统分析。结果表明：（1）洞穴滴水的离子主要来源于岩石风化，水化学类型为 HCO·Ca-Mg 和 HCO-SO·Ca-Mg。（2）硫和氧同位素表明，双河洞洞穴水中的硫酸盐主要来自土壤硫酸盐和化肥的混合。（3）Simmr 模型表明，各滴水点硫酸盐的主要来源是自然源，如土壤硫酸盐和石膏溶解。自然源对洞穴水中硫酸盐的贡献率超过 80%，受人为活动影响较小。（4）硫酸引起的碳酸盐风化（CSW）可以加速岩石风化和方解石沉淀效应，通过裂隙管道涉及区域 CO 交换。正向模型结果表明，CSW 使 SQ2#、PB 和 MH6#的岩溶碳汇分别减少了约 19.44%、23.88%和 12.74%。因此，在评估岩溶地区碳源和碳汇过程时，这种影响不容忽视。
