作者：Kong, L., Xu, H., Wang, Y., Tao, Y., Xiao, P., Wang, Z., Zhang, M., Zheng, X., Zhang, C., Cui, S., Xu, T., Pang, Z., Wang, A., Ren, N. & Zheng, C.

As external phosphorus inputs are progressively brought under control, microbe-mediated release of legacy phosphorus from sediments to the overlying waters has become a primary contributor to persistent eutrophication and recurrent algal blooms in global freshwater ecosystems. However, inherent challenges exist in capturing the in situ metabolic activity of phosphorus-solubilizing bacteria (PSB) due to intrinsic cultivation biases and the disconnect between bulk metagenomic profiles and the functions of viable cells. Furthermore, a lack of research into the coupling the phenotypic activity and adaptive genetic strategies of PSB in heterogeneous sedimentary environments has led to limited understanding of the mechanisms underlying endogenous phosphorus release. Here, using single-cell Raman spectroscopy coupled with deuterium oxide labeling (Raman-D2O), distinct in situ phosphorus-solubilizing activities of PSB inhabiting eutrophic, mesotrophic, and oligotrophic sediments were quantified. Inorganic PSB dominated in all sediment types but exhibited the highest activity in nutrient-rich eutrophic sites. Their activities correlated strongly with phosphorus speciation and release fluxes at the sediment-water interface of their habits. In contrast, organic PSB prevailed in oligotrophic sediments. Raman-activated cell sorting conbined with metagenomic sequencing uncovered that low-abundance taxa (e.g., Bacillus and Acinetobacter ) acted as disproportionate drivers of phosphorus mobilization. PSB from eutrophic sediments were enriched in genes encoding phosphatases and organic acid hydrolysis pathways, whereas their oligotrophic counterparts favored genes related to high-affinity transporters and polyphosphate storage. These findings elucidate how nutrient regimes shape PSB metabolic traits, advancing mechanistic insights into microbial phosphorus dynamics in aquatic ecosystems and providing a theoretical basis for optimizing lake management strategies to mitigate endogenous pollutant-driven eutrophication risks.

随着外源磷输入逐步得到控制，由微生物介导的沉积物遗留磷向水体释放的过程，已成为全球淡水生态系统持续性富营养化和周期性藻华的主要贡献因素。然而，受限于固有的培养偏差以及宏基因组整体谱与活细胞功能之间的脱节，准确捕捉解磷菌的原位代谢活性本身存在挑战。此外，由于对异质性沉积环境中解磷菌表型活性与适应性遗传策略的耦合关系研究不足，目前对内源磷释放机制的理解仍十分有限。本研究利用单细胞拉曼光谱结合重水标记技术（Raman-D₂O），定量表征了栖息于富营养、中营养和贫营养沉积物中解磷菌的明显不同的原位溶磷活性。结果显示，无机解磷菌在所有沉积物类型中均占主导地位，但在营养丰富的富营养样点表现出最高活性，其活性与栖息地沉积物-水界面的磷形态及释放通量密切相关。相比之下，有机解磷菌在贫营养沉积物中占据优势。通过拉曼激活细胞分选结合宏基因组测序发现，低丰度类群（如芽孢杆菌属和不动杆菌属）不成比例地充当了磷动员的主要驱动者。来自富营养沉积物的解磷菌富含编码磷酸酶和有机酸水解途径的基因，而贫营养环境中的解磷菌则偏好与高亲和力转运蛋白和多聚磷酸盐储存相关的基因。这些发现阐明了营养状态如何塑造解磷菌的代谢特性，深化了对水生生态系统微生物磷动态的机制性认识，并为优化湖泊管理策略以缓解内源污染物驱动的富营养化风险提供了理论依据。

（来源：Environmental Science & Technology 2026 Issue 6  DOI: 10.1021/acs.est.5c15684）