Ni Zhaokui, Huang Dongling, Li Yu, Liu Xiaofei, Wang Shengrui
Guangdong-Hong Kong Joint Laboratory for Water Security, Center for Water Research, Advanced Institute of Natural Sciences, Beijing Normal University at Zhuha, Beijingi, 519087, China; College of Water Sciences, Beijing Normal University, Beijing 100875, China; Engineering Research Center of Ministry of Education on Groundwater Pollution Control and Remediation, College of Water Sciences, Beijing Normal University, Beijing 100875, China.
College of Resource Environment and Tousism, Capital Normal University, Beijing 100048, China.
Water Res. 2022 May 1;214:118197. doi: 10.1016/j.watres.2022.118197. Epub 2022 Feb 14.
Organic phosphorus (P) plays a key role in eutrophication and ecological equilibrium in lake systems. However, characterizing the composition of P in lake sediments has been a bottleneck hindering further understanding of the biogeochemical cycle of P. Here, multiple methods of P NMR spectroscopy and molecular weight (MW) ultrafiltration were combined to detect P composition characteristics from a novel angle in ten lake sediments of China. The results showed that sediment P mainly consisted of monoester (mono-P, 14±8.8% of the NaOH-EDTA total P on average), diester (di-P, 1.4±1.4%) and phosphonate (phos-P, 0.1±0.1%), while the abundance of P was largely underestimated by P NMR methods. Some specific species of mono-P were successfully determined, and the contents of these species followed a decreasing order: inositol hexakisphosphate (IHP6) > RNA mononucleotides (RNA-mnP) > β-glycerophosphate (β-gly) > D-glucose 6-phosphate (Glu-6) > α-glycerophosphate (α-gly), which was largely dependent upon their bioreactivity. A significant relationship between MW and P components was observed despite the great differences among sediment samples. For refractory P components, IHP6 was mainly rich in the MW < 3 kDa while phos-P was almost only detected in the MW > 3 kDa, which largely attributed to their metal binding affinities and characteristics. The abundance of bioreactive P species (α-gly, β-gly, Glu-6, di-P) in high MW (HMW, > 3 kDa) were all higher than that of low MW (LMW, < 3 kDa) due to microbial degradation and self-assembly. If the HMW organic molecules were biologically and chemically more reactive than its LMW counterparts, the high percentage of α-gly, β-gly, glu-6 and di-P in the HMW portion would highlights their high reactivity from the perspective of MW. These insights revealed the dynamics of the MW distribution of P components and provide valuable information to better understand the P composition and bioreactivity in sediments.
有机磷（P）在湖泊系统的富营养化和生态平衡中起着关键作用。然而，表征湖泊沉积物中磷的组成一直是阻碍进一步理解磷生物地球化学循环的瓶颈。在此，将多种磷核磁共振光谱法和分子量（MW）超滤方法相结合，从一个新的角度检测了中国十个湖泊沉积物中的磷组成特征。结果表明，沉积物磷主要由单酯（单磷，平均占NaOH-EDTA总磷的14±8.8%）、二酯（双磷，1.4±1.4%）和膦酸盐（膦磷，0.1±0.1%）组成，而磷核磁共振方法在很大程度上低估了磷的丰度。成功测定了一些特定的单磷物种，这些物种的含量顺序为：肌醇六磷酸（IHP6）>RNA单核苷酸（RNA-mnP）>β-甘油磷酸（β-gly）>D-葡萄糖6-磷酸（Glu-6）>α-甘油磷酸（α-gly），这在很大程度上取决于它们的生物反应性。尽管沉积物样品之间存在很大差异，但观察到分子量与磷组分之间存在显著关系。对于难降解的磷组分，IHP6主要富集在分子量<3 kDa的部分，而膦磷几乎只在分子量>3 kDa的部分检测到，这在很大程度上归因于它们与金属的结合亲和力和特性。由于微生物降解和自组装，高分子量（HMW，>3 kDa）中生物活性磷物种（α-gly、β-gly、Glu-6、双磷）的丰度均高于低分子量（LMW，<3 kDa）。如果高分子量有机分子在生物学和化学上比低分子量有机分子更具反应性，那么高分子量部分中α-gly、β-gly、glu-6和双磷的高比例将从分子量的角度突出它们的高反应性。这些见解揭示了磷组分分子量分布的动态变化，并为更好地理解沉积物中磷的组成和生物反应性提供了有价值的信息。
