Characteristics and distribution of phosphorus in surface sediments of a shallow lake

Phosphorus ( P ) in sediments plays an important role in shallow lake ecosystems and has a major effect on the lake environment. The mobility and bioavailability of P primarily de-pend on the contents of different P forms, which in turn depend on the sedimentary en-vironment. Here, sediment samples from Baiyangdian (BYD) lake were collected and mea-sured by the Standards, Measurements, and Testing procedure and Phosphorus-31 nuclear magnetic resonance spectroscopy (31P NMR) to characterize different P forms and their re-lationships with sediment physicochemical properties. The P content in the sediments var-ied in different areas and had characteristics indicative of exogenous river input. Inorganic P (334-916 mg/kg) was the dominant form of P . The 31P NMR results demonstrated that orthophosphate monoesters (16-110 mg/kg), which may be a source of P when redox con-ditions change, was the dominant form of organic P (20-305 mg/kg). The distribution of P forms in each region varied greatly because of the effects of anthropogenic activities, and the regions affected by exogenous river input had a higher content of P and a higher risk of P release. Principal component analysis indicated that P bound to Fe, Al, and Mn oxides and hydroxides (NaOH-P) and organic P were mainly derived from industrial and agricul-tural pollution, respectively. Redundancy analysis indicated that increases in pH lead to the release of NaOH-P. Organic matter plays an important role in the organic P biogeochemical cycle, as it acts as a sink and source of organic P . (c) 2022 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.

Automated summary

This study analyzed sediment samples from Baiyangdian Lake and found variations in the forms and content of phosphorus (P) in different regions. Inorganic P was the dominant form, while organic P was mainly in the form of orthophosphate monoesters. Regions affected by human activities had higher P content and a greater risk of P release. P bound to Fe, Al, and Mn oxides and hydroxides, as well as organic P, were derived from industrial and agricultural pollution, respectively. Organic matter played a crucial role in the organic P biogeochemical cycle.