Responses to changes in phosphorus forms in sediments of different types of lakes during the freezing period driven by microbial and environmental media

The Yellow River basin is an important ecological barrier and economic development belt in China, and its ecological protection and high-quality development have been elevated to a national strategy. The comparative study of the transformation patterns among sediment phosphorus forms in different types of lakes is a global issue in lake ecosystems. However, the interactions between sediment phosphorus forms-environmental factors-microorganisms vary with the nutrient status of lakes. In this study, we combined sequential extraction and metagenomics sequencing to assess the characteristics of phosphorus forms and transformation in sediments from different types of lakes in the Inner Mongolia section of the Yellow River basin, and further explored the response of relevant microbial and environmental drivers to phosphorus forms transformation and bioavailability in sediments. The main findings are as follows: the sediments of all three lakes exhibited strong exogenous pollution input characteristics, but N and P pollution were not homogenous. Higher eutrophication conditions lead to enhanced sediment phosphorus forms transformation, and the special ecological environment also affects phosphorus forms transformation. The transformation capacity of sediment phosphorus forms also differs among different types of lakes. Different drivers reflect the mutual control of WA-P, PA-P, NaOH-P and HCl-P on Bio-P. There were significant differences in bacterial community diversity and composition between different types of lakes at the same latitude (p<0.05), and the role of phosphorus forms was stronger in sediments of lakes with rich biodiversity. The recovery of lake eutrophication was somewhat hindered by the microbial interactions of phosphorus cycling and phosphorus forms within the sediment. This study provides data and theoretical support for exploring the commonalities and differences among different types of lakes in the Inner Mongolia section of the Yellow River Basin, and is representative and typical for promoting the optimization of ecological security patterns in ecologically fragile watersheds.