Wu Rong, Shi Xiaohong, Kang Xueer, Zhang Sheng, Zhao Shengnan, Liu Yu, Sun Biao, Lu Junping, Yu Haifeng, Wang Shihuan, Pan Xueru, Shen Kaiqi, Arvola Lauri, Yan Jianghong, Hao Rong, Shi Ruijia
Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot 010018, China; Ordos City water resources protection and utilization center, Ordos 017200, China.
Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot 010018, China; State Gauge and Research Station of Wetland Ecosystem, Wuliangsuhai Lake, Inner Mongolia, China.
J Contam Hydrol. 2025 Jul;273:104598. doi: 10.1016/j.jconhyd.2025.104598. Epub 2025 May 11.
Nitrogen and phosphorus play pivotal roles in determining the eutrophic conditions and nutrient provision in lakes. However, the mechanisms and processes of nutrient release at the sediment-water interface of shallow lakes in cold regions remain unclear, especially under the complex environmental conditions of freezing and open-water periods. Therefore, Diffusive Gradients in Thin-films (DGT) and High-resolution Peeper technologies (HR-Peeper) were used to investigate the nitrogen and phosphorus characteristics of the sediment water interface, and the process of bacteria affecting the nitrogen and phosphorus cycle was clarified by the high-throughput sequencing technology. The results indicated that sediment phosphorus (PO) flux ranged from -1.39 to 3.6 mg/m·d, with the interstitial water-Soluble Reactive PO presenting notable fluidity and potential bioavailability. The ammonia nitrogen (NH-N) flux varied from -4.71 to 3.65 mg/m·d. The nitrate nitrogen (NO-N) flux varied from -11.64 to 1.18 mg/m·d, exhibiting an opposite trend to NH-N, which was released into water bodies during the freezing period and migrated to the sediments in the open water period. Common metabolic pathways and functional genes for nitrogen and phosphorus were identified in Methylomicrobium, Marinobacter, and Psychrobacter. The dissimilatory nitrate reduction to ammonium (DNRA) facilitated the transformation of polyphosphates and the release of phosphorus. Water temperature indirectly regulated the fluxes of nitrogen and phosphorus at the sediment-water interface (SWI) by modulating the microbial abundance and dissolved oxygen (DO) content.
氮和磷在决定湖泊的富营养化状况和养分供应方面起着关键作用。然而，寒冷地区浅水湖泊沉积物-水界面的养分释放机制和过程仍不明确，尤其是在结冰期和敞水区等复杂环境条件下。因此，采用薄膜扩散梯度技术（DGT）和高分辨率peeper技术（HR-Peeper）研究沉积物-水界面的氮磷特征，并通过高通量测序技术阐明细菌影响氮磷循环的过程。结果表明，沉积物磷（PO）通量范围为-1.39至3.6mg/m·d，间隙水可溶性活性磷表现出显著的流动性和潜在生物有效性。氨氮（NH-N）通量在-4.71至3.65mg/m·d之间变化。硝态氮（NO-N）通量在-11.64至1.18mg/m·d之间变化，与NH-N呈现相反趋势，在结冰期释放到水体中，在敞水区迁移到沉积物中。在甲基微菌属、海杆菌属和嗜冷杆菌属中鉴定出了常见的氮磷代谢途径和功能基因。异化硝酸盐还原为铵（DNRA）促进了多磷酸盐的转化和磷的释放。水温通过调节微生物丰度和溶解氧（DO）含量间接调节沉积物-水界面（SWI）的氮磷通量。
