River Ecological Health Assessment Based on Microbial Integrity Index and Water Quality Index
Urban river ecosystems are increasingly threatened by anthropogenic activities, necessitating comprehensive health assessments beyond conventional water quality metrics. This study evaluates the ecological health of the Zhongshan South Road reach in Wuhu, China, by integrating microbial community integrity with physicochemical parameters. Nine monitoring sections were established, considering land use, pollution sources, and seasonal hydrology. Over four seasons, eight water quality parameters and microbial indicators were systematically monitored. A Microbial Index of Biotic Integrity (M-IBI) was developed through candidate parameter screening, interference response analysis, and discriminant ability assessment. Core metrics included Chao1 index, Sobs index, and relative abundances of Acinetobacter and hgcl-clade genera. M-IBI scores were standardized and classified into health levels, with results compared against the Water Quality Index (WQI). Findings revealed seasonal M-IBI variation: winter > autumn > summer > spring, with downstream water quality superior to upstream. Spatial and seasonal patterns of WQI and M-IBI were largely concordant, though discrepancies arose from differential microbial responses to environmental factors and heightened sensitivity to human disturbance. The M-IBI approach demonstrated robust applicability for river health assessment, offering a sensitive, integrative tool for urban water management.