Lu Lan, Tang Ning, Zhu Ziqian, Wang Ronghan, Gao Xiang, Yan Min, Hu Tingting, Ma Han, Li Guoyu, Li Weixiang, Zhang Jingyi, Li Xiaodong, Liang Jie
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China.
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China.
Environ Res. 2025 Apr 1;270:120966. doi: 10.1016/j.envres.2025.120966. Epub 2025 Jan 27.
Internal nutrient cycling, especially phosphorus (P), is of great influence in lake eutrophication. Dissolved organic matter (DOM) and microorganisms are ubiquitous in the sediments and closely associated with P-cycling. However, the underlying interactions of DOM, microorganisms and P in floodplain lake area with different hydrological characteristics remain scarce. This study evaluated the P and DOM properties, P functional genes and microbial community ranging from channel to stagnant to grass area (CA, SA, GA) in a floodplain lake, respectively. The results showed that sediments dissolved organic carbon (DOC) and total P (TP) gradually decreased from GA to SA to CA. Organic P (64.44%) and Fe-bound P (34.86%) were primary bioavailable P fractions in three areas. Water Chl-a, DO, DOC and fulvic-like C1 component were essential driving factors affecting the distribution of P in sediments (p < 0.05). Microbial diversity, community structure and P-cycling function were significantly different in three areas and closely associated with sediment P and DOM (p < 0.05). The co-occurrence network analysis revealed that the interconnection of microbial communities, DOM components and P fractions decreased from CA (node: 123, edge: 1399) to SA (node: 122, edge: 667) to GA (node: 119, edge: 521). Sediment microbial communities enhanced P cycling via mineralizing organic P and dissolving inorganic P (Ca-P) in CA and coupling DOM mineralization and Fe-P dissolution in SA, while sediment in GA owned the significant potential of P and DOM storage and the abundant P-cycling genes. This finding provides further understanding that underlying mechanisms of internal P-cycling in floodplain lake ecosystem.
内部养分循环，尤其是磷（P）循环，对湖泊富营养化有很大影响。溶解有机物（DOM）和微生物在沉积物中普遍存在，且与磷循环密切相关。然而，在具有不同水文特征的河漫滩湖泊区域，DOM、微生物和磷之间潜在的相互作用仍鲜为人知。本研究分别评估了河漫滩湖泊从河道区域到滞水区再到草地区域（CA、SA、GA）的磷和DOM特性、磷功能基因及微生物群落。结果表明，沉积物溶解有机碳（DOC）和总磷（TP）从GA到SA再到CA逐渐降低。有机磷（64.44%）和铁结合磷（34.86%）是三个区域主要的生物可利用磷组分。水体叶绿素a、溶解氧、DOC和类富里酸C1组分是影响沉积物中磷分布的重要驱动因素（p < 0.05）。三个区域的微生物多样性、群落结构和磷循环功能存在显著差异，且与沉积物磷和DOM密切相关（p < 0.05）。共现网络分析表明，微生物群落、DOM组分和磷组分之间的相互联系从CA（节点：123，边：1399）到SA（节点：122，边：667）再到GA（节点：119，边：521）逐渐减少。沉积物微生物群落在CA区域通过矿化有机磷和溶解无机磷（钙磷）增强磷循环，在SA区域通过耦合DOM矿化和铁磷溶解增强磷循环，而GA区域的沉积物具有显著的磷和DOM储存潜力以及丰富的磷循环基因。这一发现有助于进一步理解河漫滩湖泊生态系统中内部磷循环的潜在机制。
