Mangroves, a major ecosystem for carbon sequestration, have been recently identified as a microplastic sink, yet the impact of microplastics on the mangrove microbial community is poorly known. Here, we investigated the metabolic activities of mangrove rhizosphere microbiome in the presence of polyethylene, polystyrene, polyamide, and polyvinylchloride, in microcosms, using Biolog™ Ecoplates. Results show that microbial communities in mangrove sediment hold their functional diversity and comprehensive metabolic activity within 56 days of microplastic exposure. However, polyamide and polyvinylchloride microplastics induced a 59.6–66.7% reduction in the rhizosphere microbes’ utilization for their preferred polymer carbon sources. Microbes exposed to polyethylene microplastics showed an activated biotransformation for nitrogen-contained carbon sources. Polyethylene and polyamide microplastics caused a 20.1–22.4% loss available nitrogen. Overall, microplastics are altering the carbon and nitrogen metabolism activities of microbiomes in mangrove wetlands.

红树林是碳固存的主要生态系统，最近被确定为微塑料汇，但微塑料对红树林微生物群落的影响却鲜为人知。在这里，我们使用 Biolog™ Ecoplates 在微观世界中研究了聚乙烯、聚苯乙烯、聚酰胺和聚氯乙烯存在下红树林根际微生物组的代谢活动。结果表明，红树林沉积物中的微生物群落在微塑料暴露的 56 天内保持其功能多样性和综合代谢活性。然而，聚酰胺和聚氯乙烯微塑料导致根际微生物对其首选聚合物碳源的利用减少了 59.6-66.7%。暴露于聚乙烯微塑料的微生物表现出对含氮碳源的活化生物转化。聚乙烯和聚酰胺微塑料导致有效氮损失 20.1-22.4%。总体而言，微塑料正在改变红树林湿地微生物组的碳和氮代谢活动。