Analysis of bacterial biodiversity and ecological risk evaluation of organophosphorus in Lianhuan Lake

PLOS One | https://doi.org/10.1371/journal.pone.0332712 September 26, 2025 12 / 20 3.5 Analysis of the correlation between environmental variables and microorganisms The correlation between environmental variables and microorganisms (Fig 4) showed that the first two axes jointly explained 72.06% of the variance. Factors were ranked by their absolute loadings on CCA1—which explained the larg- est share of variance—so that longer projections on this axis indicated stronger influence; the order of influence of envi- ronmental factors on bacterial community structure was pH > TP > DO > TN > NH₃–N > NO₂–N > WT. The pH level had the greatest impact on water samples. This is because most aquatic microbes thrive in conditions that are neutral or slightly alkaline. However, excessive pH values, either too acidic or too alkaline, could hinder the development and metabolism of microorganisms and disrupt their activities. TP had the second highest impact. Phosphorus-metabolizing microorgan- isms relied on enzymes such as phosphatases for phosphorus metabolism, and the activity of these enzymes was highly dependent on the pH of the environment. Enzyme activity is highest in the optimal pH environment, which promoted the efficient utilization and conversion of phosphorus [47]. W1, W2, W3 and W4 were positively correlated with WT, DO and pH. N1, N2, N3, N4, N5 and W5 were positively correlated with TP, NH₃–N, NO₂–N and TN. To further analyze organic phosphorus in lakes and conduct ecological safety evaluations had important implications. In general, the effect of phos-

phorus on the bacterial community structure was more significant, the terrain in northern China is flat, the soil is fertile, per-capita arable land was higher, agricultural cultivation was more developed, and the main source of phosphorus pollu- tion in shallow lakes was the application of pesticides and fertilizers; further analysis of the distribution of organic phos- phorus in Lianhuan Lake and its ecological security was very necessary. Fig 4. CCA analysis at the genus level. https://doi.org/10.1371/journal.pone.0332712.g004