Physicochemical Characterization and Microbial Diversity of Calcareous Water in Huanglong Ravine, China—A World’s Heritage Site

Huanglong ravine (a world heritage site) is famous for its calcareous sinter landscape. Influenced by geomorphology, climate, hydrodynamic conditions, and biology, the overflow of CO2 in the water causes CaCO3 to over-saturate, allowing for the deposition of calcareous sinter. Among them, microorganisms play an important role in the formation of calcareous sinter. In order to investigate the physicochemical characteristics and microbial diversity of Huanglong ravine water, we measured the water quality and analyzed the microbial diversity in Huanglong ravine water samples by high-throughput sequencing method. The results showed that the TP (total phosphorus) and TN (total nitrogen) in Huanglong ravine water were 0.2–0.3 and 0.46–2.09 mg/L, respectively. Most of the sampling sites were moderately eutrophication. The abundance of Acinetobacter (9.55–67.13%), Pseudomonas (5.67–45.94%) and Brevundimonas (2.26–8.89%) was higher. The microbial community of Huanglong ravine water showed some positive correlation with the TP and TN. This study helps to diagnose the causes of algal blooms in Huanglong ravine and provides a scientific basis for the conservation of Huanglong ravine calcareous landscape.