红树林
环境化学
微观世界
生态系统
氮气循环
硝酸盐
环境科学
硝化作用
营养物
碳循环
生物地球化学循环
铵
氮气
总有机碳
湿地
沉积物
营养循环
生态学
化学
生物
有机化学
古生物学
作者
Zetao Dai,Ning Zhang,Xiao Ma,Feifei Wang,Jie Peng,Song Yang,Wenzhi Cao
标识
DOI:10.1016/j.envint.2024.108546
摘要
Mangrove wetlands are hotspots of the global nitrogen (N) cycle and important sinks of microplastics (MPs) due to their ecotone location between terrestrial and marine ecosystems. However, the effects of MPs on N cycle processes in mangrove ecosystems are still poorly understood. Thus, the present study assessed the impacts by adding MPs to mangrove sediments in a microcosm incubation experiment. The results showed that MPs increased dissolved organic carbon and nitrate but reduced ammonium contents in the sediments. MPs increased C:N stoichiometric and N:C-acquiring enzymatic ratios, indicating an intensified N limitation in mangrove sediments following exposure of MPs. MPs decreased microbial community diversity and shifted sediment microbial communities from r- to K-strategists, consistent with the intensified N limitation. In response, dissimilatory nitrate reduction to ammonium (DNRA) rates increased while nitrous oxide (N2O) production reduced suggesting more efficient N utilization in MPs treatments. The MPs with heteroatoms such as PLA- and PVC-MPs, increased DNRA rates by 67.5-78.7%, exhibiting a stronger impact than PE-MPs. The variation partitioning analysis revealed that the variances of DNRA rates and N2O production could be attributed to synergistic effects of physicochemical properties, nutrient limitation, and microbial community in mangrove sediments. Overall, this study provides pertinent insights into the impacts of MPs as a new carbon source on nutrient limitation and N turnover in mangrove ecosystems.
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