Abstract:

Studying the spatial distribution and influencing factors of biogenic elements is crucial for effective water quality management.We analyze changes in biogenic elements during dry season in the Guanshan River,a major tributary of the Danjiangkou Reservoir.We employed GeoDetector to assess the individual and interactive effects of meteorological conditions,terrain,land use,human activities,and other factors on biogenic elements. Findings indicate that during dry season,the Guanshan River is slightly alkaline and predominantly oxygen-rich,and exhibits significant spatial variability in parameters such as dissolved oxygen (DO) and total dissolved solids (TDS) along the main stream,though basic physical and chemical parameters do not differ notably between the main stream and tributaries. Inorganic carbon predominates in the river’s dissolved carbon content. The concentrations of carbon (C),nitrogen (N),phosphorus (P),and silicon (Si) are lower compared to some southern rivers in China,with notable spatial variations. The river does not exhibit eutrophication,and its water quality is generally good. A correlation exists among the concentrations of biogenic elements,with variations in dissolved inorganic carbon (DIC) and dissolved silicon (DSi) mass concentrations being effectively explained by precipitation,temperature,and elevation. Interactions among land use types and between land use and factors such as precipitation significantly enhance the interpretation of changes in biogenic element concentrations. These results are important for water environmental protection in the water conservation area of the Middle Route of the South-to-North Water Diversion Project.

Key words: biogenic elements, GeoDetector, influencing factors, water quality analysis, middle route project of South-to-North Water Diversion, Guanshan River Basin