Characterization and sources of dissolved and particulate phosphorus in 10 freshwater lakes with different trophic statuses in China by solution 31P nuclear magnetic resonance spectroscopy.

Information on dissolved phosphorus (DP) and particulate phosphorus (PP) is essential to evaluate the P dynamics and control eutrophication. In this work, DP and PP in 10 freshwater lakes representing various trophic statuses were analyzed by solution 31P nuclear magnetic resonance spectroscopy. The results indicated that the predominant forms of DP and PP were orthophosphate (Ortho‐P) and monoester phosphate (Mono‐P). There was a greater concentration of Ortho‐P and Mono‐P in the water and particulate matter of medium‐eutriphic lakes than in lightly eutriphic or mesotrophic lakes. α‐Glycerophophate (2.7–32.5%), β‐glycerophosphate (1.3–23.4%), guanosine 2′Mono‐P (20.2–29.3%), inositol hexakisphosphate (IHP) (8.3–36.4%) and nicotinamide adenine dinucleotide (NAD) (17.3–35.9%) were identified as the major chemical forms of Mono‐P in water and particulate matter, which originate mainly from the degradation of labile diesters, aquatic/microbial sources and a combination of terrestrial and aquatic/microbial sources. Diester phosphate (Di‐P) was dominated by teichoic acid (0.5–14.8%) and deoxyribonucleic acid (DNA) (0.6–17.7%), which originated from aquatic/microbial sources. Moreover, correlation analysis showed that dissolved Mono‐P in water and particulate matter had a positive correlation with chlorophyll‐a (Chl‐a), which indicated their potential bioavailability for algal activity. pH was a crucial parameter to control Di‐P, pyrophosphate (Pyro‐P) and polyphosphate (Poly‐P) in water. Mono‐P/PPs showed a positive correlation with Chl‐a (R2 = 0.459), total phosphorus (TP) (R2 = 0.586) and the trophic status index (R2 = 0.588), which suggested that particulate Mono‐P can potentially contribute to lake eutrophication. Both Ortho‐P and Mono‐P were major contributors of P nutrients for algae, and therefore source control and new techniques are needed for reducing eutrophication. • Dissolved phosphorus and particulate phosphorus forms in lakes representing various trophic status were investigated. • Ortho‐P and Mono‐P in water and particulate matters showed a greater concentration in mid‐eutrophic lakes. • Dissolved and Particulate Mono‐P processed a potential contribution to lake eutrophication. [ABSTRACT FROM AUTHOR]