Characterization and source identification of organic phosphorus in sediments of a hypereutrophic lake

Hezhong Yuan; Ziqiu Tai; Qiang Li; Fengmin Zhang

doi:10.1016/j.envpol.2019.113500

Characterization and source identification of organic phosphorus in sediments of a hypereutrophic lake

Environ Pollut. 2020 Feb:257:113500. doi: 10.1016/j.envpol.2019.113500. Epub 2019 Oct 31.

Authors

Hezhong Yuan¹, Ziqiu Tai², Qiang Li³, Fengmin Zhang⁴

Affiliations

¹ Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control and Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CICAEET), School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China. Electronic address: yuanhezhong@nuist.edu.cn.
² Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control and Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CICAEET), School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.
³ Department of Plant and Soil Sciences, University of Delaware, Newark, DE, 19716, United States.
⁴ Testing Center, Yangzhou University, Yangzhou 225009, China.

PMID: 31733975
DOI: 10.1016/j.envpol.2019.113500

Abstract

High phosphorus (P) load and consequent algal bloom are critical issues because of their harmful effects to aquatic ecosystems. The organic phosphorus (Po) cycling and hydrolyzation pathway in the sediments of a hypereutrophic lake area with high algae biomass were investigated using stable isotopes (δ¹³C and δ¹⁵N) along with C/N ratios, a sequential extraction procedure, ³¹P NMR spectrum, and alkaline phosphatase activity (APA) was measured simultaneously. C/N ratios lower than 10 combined with lighter δ¹³C (-23.5 to -25.2‰) and δ¹⁵N values (3.7-9.5‰) indicated that endogenous algal debris contributed to the predominant proportions of P-containing organic matter in the sediments. Sequential extraction results showed that Po fractions decreased as nonlabile Po > moderately labile Po > biomass-Po. Decreasing humic-associated Po (HA-Po) in sediments downward suggested the degradation of high-molecular-weight Po compounds on the geological time scale to low-molecular-weight Po including fulvic-associated Po (FA-Po), which is an important source of labile Po in the sediment. An analysis of the solution ³¹P NMR spectrum analysis showed that important Po compound groups decreased in the order of orthophosphate monoesters > DNA-Po > phospholipids. The significant correlation indicated that orthophosphate monoesters were the predominant components of HA-Po. Rapid hydrolysis of labile orthophosphate diesters further facilitated the accumulation of orthophosphate monoesters in the sediments. Additionally, the simultaneously upward increasing trend demonstrated that APA accelerated the mineralization of Po into dissolved reactive phosphorus (DRP), which might feed back to eutrophication in algae-dominant lakes. The significantly low half-life time (T_1/2) for important Po compound groups indicated faster metabolism processes, including hydrolysis and mineralization, in hypereutrophic lakes with high algae biomass. These findings provided improved insights for better understanding of the origin and cycling processes as well as management of Po in hypereutrophic lakes.

Keywords: Alkaline phosphatase activity (APA); Hypereutrophic lake; Organic phosphorus; Sediment; Solution (31)P NMR; Source identification.

MeSH terms

Biomass
China
Ecosystem
Eutrophication
Geologic Sediments / chemistry
Hydrolysis
Lakes / chemistry
Magnetic Resonance Spectroscopy / methods
Phosphates / analysis
Phosphorus / analysis*
Water Pollutants, Chemical / analysis*

Substances

Phosphates
Water Pollutants, Chemical
Phosphorus