Work

Phosphorus Regulated Coordination of Carbon, Nitrogen, Sulfur and Phosphorus Cycling Genes in Sediments of a Plateau Mesotrophic Lake Erhai in Yunnan, China

Year: 2025

Type: article

Abstract: Eutrophication threatens vulnerable plateau lakes, yet the gene-level microbial processes behind spatial heterogeneity of sediment carbon (C), nitrogen (N), phosphorus (P) and sulfur (S) cycling and their environmental driver remain unclear. This study first applies the high-throughput Quantitative Microbial Ecology Chip (QMEC) to quantify 71 functional genes involved in geochemical cycling in sediment of a large Chinese plateau lake, Erhai, aiming to elucidate how environmental factors shape the spatial distribution and coupling patterns of these genes. The results revealed that total functional gene abundance exhibited a pronounced south-to-north decline, with key genes (rbcL, mct, nirS, nosZ, phoD, pqqC and yedZ) being significantly higher in the southern sector (p < 0.05). Lignocellulose-degrading genes (abfA, xylA and mnp) exceeded 106 copies g−1 and were significantly enriched in the south, indicating faster organic-matter turnover. Denitrification dominated the nitrogen cycle, with nirS-type denitrifiers being overwhelmingly prevalent; genes associated with nitrate reduction (napA, narG) were also significantly more abundant in the south. Sediment total phosphorus (TP) was significantly correlated with genes involved in carbon fixation, methane production, nitrogen fixation and sulfur metabolism (Mantel test, p < 0.05), suggesting that TP is a key driver of microbial nutrient cycling in Erhai sediment. Furthermore, co-abundance of these functional genes was observed across all sites (Spearman correlation, p < 0.05), which in turn implies potential coupling of the major elemental cycles. Accordingly, the differentiation of the carbon, nitrogen, phosphorus and sulfur cycling genes and metabolic potential in the different sectors reveals heterogeneous microbial regulation of Erhai’s endogenous nutrient cycling. It highlights precision and differentiated management as a key for large lake restoration.

Source: Water

DOI: 10.3390/w17233399