Biao Zhang, Jiajun Li, Yansong Li, Xiangyu Guan, Lihua Wang, Guangshuai Zhang, Dandan Wang, Yuntao Xing, Rujia Li
School of Ocean Science, China University of Geosciences, Beijing, China; The Fifth Geology Company of Hebei Geology & Minerals Bureau, Tangshan, Hebei, China; Key Laboratory of Marine Ecosystem Restoration, Ministry of Ecology and Environment, Dalian, Liaoning, China; Key Laboratory of Ecological Prewarning, Protection and Restoration of Bohai Sea, Ministry of Natural Resources, Qingdao, Shandong, China.
The Fifth Geology Company of Hebei Geology & Minerals Bureau, Tangshan, Hebei, China; Key Laboratory of Marine Ecosystem Restoration, Ministry of Ecology and Environment, Dalian, Liaoning, China; Key Laboratory of Ecological Prewarning, Protection and Restoration of Bohai Sea, Ministry of Natural Resources, Qingdao, Shandong, China.
Mar Environ Res. 2025 Sep;210:107283. doi: 10.1016/j.marenvres.2025.107283. Epub 2025 Jun 7.
With the change of global climate and the intensification of human activities, the pollutant load in estuary is increasing. Large estuary and small estuary have different environmental characteristics and ecological functions. This study compared sediment physicochemical properties, microbial communities, and functional genes in a large estuary (Luanhe Estuary = 'LHE') and a small estuary (Shuanglong Estuary = 'SLE') to characterize how estuarine scale influences microbial ecosystems and nitrogen cycling. Results showed significant spatial heterogeneity in environmental factors (e.g., organic matter, total nitrogen, total phosphorus) in the LHE, which drove spatial differentiation in microbial communities and functional gene profiles. In contrast, the SLE exhibited lower environmental variability and homogenized microbial compositional patterns. Microbial community assembly in the SLE was dominated by stochastic processes, leading to higher species mobility and compositional uniformity. Network analysis revealed the LHE harbored more complex, modular microbial networks with greater cohesion and functional redundancy, enhancing resilience to environmental perturbations, while the SLE's simpler linear networks were more vulnerable to stressors. Total salinity (TS), organic matter (OM), total nitrogen (TN), and total phosphorus (TP) were key drivers of microbial composition and nitrogen cycling, but their regulatory mechanisms differed: salinity indirectly influenced nitrogen cycling in the LHE via nutrient modulation, whereas direct salinity effects on microbial composition dominated the SLE's simpler metabolic networks. These findings highlight the critical role of estuarine size and hydrological dynamics in shaping microbial diversity, network stability, and biogeochemical processes, providing insights into predicting microbial responses to environmental changes in estuarine ecosystems.
随着全球气候的变化和人类活动的加剧，河口的污染物负荷不断增加。大型河口和小型河口具有不同的环境特征和生态功能。本研究比较了大型河口（滦河河口='LHE'）和小型河口（双龙河口='SLE'）的沉积物理化性质、微生物群落和功能基因，以描述河口规模如何影响微生物生态系统和氮循环。结果表明，LHE的环境因素（如有机质、总氮、总磷）存在显著的空间异质性，这驱动了微生物群落和功能基因谱的空间分化。相比之下，SLE的环境变异性较低，微生物组成模式较为均匀。SLE中的微生物群落组装主要受随机过程控制，导致更高的物种迁移率和组成均匀性。网络分析表明，LHE拥有更复杂、模块化的微生物网络，具有更强的凝聚力和功能冗余性，增强了对环境扰动的恢复力，而SLE中更简单的线性网络更容易受到压力源的影响。总盐度（TS）、有机质（OM）、总氮（TN）和总磷（TP）是微生物组成和氮循环的关键驱动因素，但其调控机制不同：盐度通过营养调节间接影响LHE中的氮循环，而盐度对微生物组成的直接影响主导了SLE中更简单的代谢网络。这些发现突出了河口规模和水文动态在塑造微生物多样性、网络稳定性和生物地球化学过程中的关键作用，为预测河口生态系统中微生物对环境变化的响应提供了见解。
