Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, 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.
Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, 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.
Water Res. 2024 Aug 15;260:121980. doi: 10.1016/j.watres.2024.121980. Epub 2024 Jun 20.
Organic phosphorus (Po) mineralization hydrolyzed by alkaline phosphatase (APase) can replenish bioavailable P load in the sediment water ecosystem of lakes. However, the understanding about the interaction between P load and bacteria community encoding APase generation in the sediment are still limited. Different P pools in the sediments from Taihu Lake, China were measured using sequential extraction procedure. The APAase activity (APA) were obtained accompanying with enzymatic dynamical parameters Vmax and Km. The abundances and diversity of gene phoD-harboring bacterial communities were assessed using high throughput sequencing. The analysis results showed the decrease of potentially bioavailable P fractions including MgCl-P and Fe-P along sampling gradient southwards together with active P concentrations in the water. Conversely, increasing APA and absolute abundance of phoD gene were found with the decreasing of P loads southwards. Positive correlation (p < 0.05) between absolute abundance and APA indicated that phoD-encoding bacteria manipulated the APA and Po mineralization. Negative correlation (p < 0.01) suggested that the APA was restrained by high P load and was promoted under low P condition. However, higher Vmax and Km values suggested that high mineralization potential of Po maintained the high concentrations of potentially bioavailable P even the APA was restricted. The abundance increase of predominant genus Cobetia (from 15.51 to 24.34 %) mirrored by the reduced Calothrix abundance (from 24.65 to 1036 %) was speculated to be responsible for the APA promotion under low P condition. Higher diversity indices in the high P scenario suggested that high P load stimulated the ecological diversity of gene phoD-encoding bacteria community. Generally, rare taxa such as Burkholderia having high connected degrees in bacterial communities together with abundant genera synergistically manipulated the phoD gene abundance and APase generation. Interaction between P fractions and bacteria encoding phoD gene determined the eutrophication status in the lacustrine ecosystem.
有机磷（Po）可被碱性磷酸酶（APase）水解矿化，从而补充湖泊沉积物-水生态系统中的生物可利用磷负荷。然而，人们对磷负荷与细菌群落编码 APase 生成之间的相互作用的了解仍然有限。本研究采用连续提取程序测定了来自中国太湖的沉积物中的不同磷库。同时，获得了相应的碱性磷酸酶活性（APA）以及酶动力学参数 Vmax 和 Km。利用高通量测序评估了 phoD 基因编码的细菌群落的丰度和多样性。分析结果表明，随着采样梯度从南向北，潜在生物可利用磷组分（包括 MgCl-P 和 Fe-P）以及水中的活性磷浓度均呈下降趋势。相反，随着磷负荷向南减少，APA 和 phoD 基因的绝对丰度均增加。绝对丰度与 APA 之间呈正相关（p<0.05），表明 phoD 编码细菌操纵了 APA 和 Po 矿化。负相关（p<0.01）表明，APA 受到高磷负荷的抑制，而在低磷条件下得到促进。然而，较高的 Vmax 和 Km 值表明，即使 APA 受到限制，Po 的高矿化潜力仍保持较高的潜在生物可利用磷浓度。优势属 Cobetia 的丰度增加（从 15.51%增加到 24.34%）和 Calothrix 的丰度减少（从 24.65%减少到 1036%），推测是在低磷条件下促进 APA 的原因。高磷条件下的多样性指数较高表明，高磷负荷刺激了基因 phoD 编码细菌群落的生态多样性。一般来说，稀有类群（如 Burkholderia）在细菌群落中具有较高的连接度，与丰富的属协同作用，操纵 phoD 基因丰度和 APase 生成。磷组分与编码 phoD 基因的细菌之间的相互作用决定了湖泊生态系统的富营养化状态。
