Adsorption-Release Characteristics of Phosphorus and the Community of Phosphorus Accumulating Organisms of Sediments in a Shallow Lake

Abstract

One of the most challenging issues for developing countries in modern times is the care and management of clean, potable drinking water sources. Accordingly, this study singled out potential contributing factors to harmful algae blooms with a particular focus on phosphorus (P) release. The potential risks of P release for the drinking water from a lake in Fujian were assessed by investigating the spatial-temporal distribution of P, its exchange capacity, and its discharge capacity in sediment, including the community composition of phosphorus accumulating organisms (PAOs) and the phosphate’s initial migration effects on sediments. Different mixed materials, including soil aggregate distributions, sorbent, fractions, adsorption-desorption of P, and the community composition of PAOs were assessed. Total phosphorus (TP) content was measured at 24.4 ± 1.2 to 563.9 ± 38.2 mg/kg, but contents displayed some spatial differences. The dominant Ps found in the sample sediments were organic phosphorus and inorganic phosphorus associated with hydroxide Fe/Al-P, which accounted for 48.6% and 43.6%, respectively, of the TP content in the lake’s central waters. The TP concentration in vertical sediment ranged from 436.2 ± 21.3 to 602.9 ± 31.4 mg/kg. The TP spatio-temporal distribution inputs varied with rainfall (p < 0.05). P deposition occurred throughout most water bodies (p < 0.05), covering extensive areas and also decreasing at lower depths. Forty-four operational taxonomic unit (OTU) phosphorus-accumulating organism types from 11 phyla were detected in the sediment samples obtained from the Sanshiliujiao Lakes region. Proteobacteria also dominated compared to the organisms with the strongest PAOs. The diversity of PAOs in summer samples was significantly higher than that of the autumn samples. These findings provide a scientific foundation for determining the future discovery of the microbial mechanisms involved in the phosphorus metabolic cycle found in reservoir sediments. Various forms of phosphorus influenced the PAO diversity, especially Fe/Al-P. Thus, the abundance of PAOs in the sediment proved to be an essential component of the P cycle and may even play a key role in regional material circulation and in causing other environmental issues.