Zhao Junkai, Lai Sheng, Cao Jian, Yu Jinli, Zou Long, Jian Minfei, Liu Shuli
College of Life Sciences, Key Laboratory of Biodiversity Conservation and Bioresource Utilization of Jiangxi Province, Jiangxi Normal University, Nanchang, 330022, China.
Jiangxi Provincial Technology Innovation Center for Ecological Water Engineering in Poyang Lake Basin, Jiangxi Academy of Water Science and Engineering, Nanchang, 330022, China.
J Environ Manage. 2025 Sep;391:126531. doi: 10.1016/j.jenvman.2025.126531. Epub 2025 Jul 13.
Under the backdrop of increasingly frequent wetland alternation between dry and wet conditions driven by global climate change, the differential impact mechanisms of microplastics (MPs) on microbial communities under drought and flooding conditions remain insufficiently characterized. This study established a sediment microcosm experimental system for Poyang Lake wetland to systematically analyze the regulatory effects of polyethylene (PE) and polypropylene (PP) microplastics on sediment bacterial community structure, functional genes, and ecological processes over 180 days under simulated drought and flooded conditions. The results demonstrated that microplastics significantly enhanced the richness (Chao1 index +95.9 %) and diversity (Shannon index +61.6 %) of sediment bacterial communities, with a more pronounced promoting effect under flooded conditions (η = 0.36). Furthermore, PE exhibited a more pronounced influence on community structure than PP, particularly under drought conditions. Under flooding microplastics upregulated nitrogen and sulfur cycling functional genes by enriching Nitrospira and Desulfatiglans, but concurrently increased the abundance of potential pathogenic bacteria (p < 0.001). Under drought conditions, Streptomyces emerged as the core genus, driving the expression of carbon metabolism genes (rho >0.56) and enhancing stress resistance. Null model analysis revealed that bacterial community succession was primarily driven by deterministic processes (contribution rate >51.3 %), while MPs restructured ecological niche by significantly reducing ammonium nitrogen (-14.35 %),and nitrate nitrogen (-13.64 %), while regulating pH and organic carbon levels. This study provides insights into the specific risks associated with "plasticosphere" formation under flooded and drought conditions: flooded conditions may exacerbate pathogen dissemination and metabolic dysregulation, whereas drought promotes carbon sequestration. Based on these findings, a hierarchical governance strategy is proposed, offering new insights for wetland ecological restoration.
在全球气候变化导致湿地干湿交替日益频繁的背景下，微塑料（MPs）在干旱和洪水条件下对微生物群落的差异影响机制仍未得到充分表征。本研究建立了鄱阳湖湿地沉积物微观实验系统，以系统分析聚乙烯（PE）和聚丙烯（PP）微塑料在模拟干旱和洪水条件下180天内对沉积物细菌群落结构、功能基因和生态过程的调控作用。结果表明，微塑料显著提高了沉积物细菌群落的丰富度（Chao1指数+95.9%）和多样性（Shannon指数+61.6%），在洪水条件下促进作用更明显（η = 0.36）。此外，PE对群落结构的影响比PP更显著，尤其是在干旱条件下。在洪水条件下，微塑料通过富集硝化螺旋菌属和脱硫菌属上调了氮和硫循环功能基因，但同时增加了潜在病原菌的丰度（p < 0.001）。在干旱条件下，链霉菌成为核心属，驱动碳代谢基因的表达（rho > 0.56）并增强抗逆性。零模型分析表明，细菌群落演替主要由确定性过程驱动（贡献率>51.3%），而微塑料通过显著降低铵态氮（-14.35%）和硝态氮（-13.64%），同时调节pH和有机碳水平，重塑了生态位。本研究揭示了洪水和干旱条件下“塑料球”形成相关的特定风险：洪水条件可能加剧病原体传播和代谢失调，而干旱则促进碳固存。基于这些发现，提出了分层治理策略，为湿地生态恢复提供了新的见解。
