State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, PR China.
Environ Pollut. 2022 Oct 15;311:119964. doi: 10.1016/j.envpol.2022.119964. Epub 2022 Aug 22.
Extensive algal bloom in the surface water is a pressing issue in Lake Dianchi that causes lake restoration to be difficult owing to complex and variable phosphorus (P) sources in the water column. P released from algae, suspended particles (SS), and sediment can provide sustainable P sources for algal blooms. However, little is known regarding the dynamic of P speciation in these substances from different sources. In this study, solution P nuclear magnetic resonance (P NMR) and chemical sequential extraction were employed to identify P speciation in algae, SS, and sediment during different periods. Results showed that dissolved inorganic P (P) directly accumulated in algae in the form of orthophosphate (ortho-P) and pyrophosphate (pyro-P). Algae preferentially utilized P, followed by organic P (P) in the water column when the P was insufficient during growth and reproduction. The P NMR spectra demonstrated that ortho-P, orthophosphate monoesters (mono-P), orthophosphate diesters (diester-P), and pyro-P dominated the P compounds across the samples tested. Increasing remineralization of SS mono-P driven by intense alkaline phosphatase activities was caused by increasing P needs of algae and pressure of P supply in the water column. The higher ratios of diester-P to mono-P in sediment (mean 0.55) than those in algae (mean 0.07) and SS (mean 0.11 in surface water, 0.14 in bottom water) suggested that the degradation and regeneration occurred within these P compounds during or after sedimentation. P content in algae during growth and reproduction was controlled by its P absorption and utilization strategies. Results of this study provide insights into the dynamic cycling of P in algae, SS, and sediment, explaining the reason for algal blooms in the surface water with low concentrations of dissolved P.
滇池水体中广泛存在的藻类水华是一个紧迫的问题，由于水柱中磷（P）来源复杂且多变，使得湖泊恢复变得困难。藻类、悬浮颗粒物（SS）和沉积物中释放的 P 可以为藻类水华提供可持续的 P 源。然而，对于这些不同来源物质中 P 形态的动态变化，人们知之甚少。在这项研究中，采用溶液 P 核磁共振（P NMR）和化学连续提取的方法，来识别不同时期藻类、SS 和沉积物中的 P 形态。结果表明，溶解无机 P（P）以正磷酸盐（ortho-P）和焦磷酸盐（pyro-P）的形式直接在藻类中积累。藻类在生长和繁殖过程中 P 不足时，优先利用水中的 P，然后是有机 P（P）。P NMR 光谱表明，ortho-P、单酯磷（mono-P）、二酯磷（diester-P）和 pyro-P 是样品中 P 化合物的主要成分。由于藻类和水柱中 P 供应的压力增加，导致碱性磷酸酶活性增强，SS 单酯磷的再矿化增加。与藻类（均值 0.07）和 SS（表层水均值 0.11，底层水均值 0.14）相比，沉积物中二酯磷与单酯磷的比值（均值 0.55）较高，表明这些 P 化合物在沉降过程中或之后发生了降解和再生。藻类在生长和繁殖过程中 P 含量受其 P 吸收和利用策略的控制。本研究结果深入了解了藻类、SS 和沉积物中 P 的动态循环，解释了低溶解 P 浓度的表层水中藻类水华的成因。
