State Key Laboratory of Organic Geochemistry and Guangdong-Hong Kong-Maco Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, No. 511, Kehua Street, Tianhe District, Guangzhou 510640, P. R. China.
Guangdong Key Laboratory of Environmental Protection and Resources and Utilization, No. 511, Kehua Street, Tianhe District, Guangzhou 510640, P. R. China.
ISME J. 2024 Jan 8;18(1). doi: 10.1093/ismejo/wrae186.
Plastic marine debris is known to harbor a unique microbiome (termed the "plastisphere") that can be important in marine biogeochemical cycles. However, the temporal dynamics in the plastisphere and their implications for marine biogeochemistry remain poorly understood. Here, we characterized the temporal dynamics of nitrifying communities in the plastisphere of plastic ropes exposed to a mangrove intertidal zone. The 39-month colonization experiment revealed that the relative abundances of Nitrospira and Candidatus Nitrosocosmicus representatives increased over time according to 16S rRNA gene amplicon sequencing analysis. The relative abundances of amoA genes in metagenomes implied that comammox Nitrospira were the dominant ammonia oxidizers in the plastisphere, and their dominance increased over time. The relative abundances of two metagenome-assembled genomes of comammox Nitrospira also increased with time and positively correlated with extracellular polymeric substances content of the plastisphere but negatively correlated with NH4+ concentration in seawater, indicating the long-term succession of these two parameters significantly influenced the ammonia-oxidizing community in the coastal plastisphere. At the end of the colonization experiment, the plastisphere exhibited high nitrification activity, leading to the release of N2O (2.52 ng N2O N g-1) in a 3-day nitrification experiment. The predicted relative contribution of comammox Nitrospira to N2O production (17.9%) was higher than that of ammonia-oxidizing bacteria (4.8%) but lower than that of ammonia-oxidizing archaea (21.4%). These results provide evidence that from a long-term perspective, some coastal plastispheres will become dominated by comammox Nitrospira and thereby act as hotspots of ammonia oxidation and N2O production.
塑料海洋垃圾中已知存在独特的微生物组（称为“塑料球层”），它们在海洋生物地球化学循环中很重要。然而，塑料球层的时间动态及其对海洋生物地球化学的影响仍知之甚少。在这里，我们描述了暴露于红树林潮间带的塑料绳的塑料球层中硝化群落的时间动态。39 个月的定植实验表明，根据 16S rRNA 基因扩增子测序分析，硝化螺旋菌和候选硝化球菌代表的相对丰度随着时间的推移而增加。宏基因组中 amoA 基因的相对丰度暗示了共氨氧化菌 Nitrospira 是塑料球层中主要的氨氧化菌，其丰度随着时间的推移而增加。共氨氧化菌 Nitrospira 的两个宏基因组组装基因组的相对丰度也随着时间的推移而增加，并与塑料球层中胞外聚合物物质的含量呈正相关，与海水中的 NH4+浓度呈负相关，表明这两个参数的长期演替显著影响了沿海塑料球层中的氨氧化群落。在定植实验结束时，塑料球层表现出高的硝化活性，导致在 3 天的硝化实验中释放出 N2O（2.52ng N2O N g-1）。共氨氧化菌 Nitrospira 对 N2O 产生的预测相对贡献（17.9%）高于氨氧化细菌（4.8%）但低于氨氧化古菌（21.4%）。这些结果表明，从长期来看，一些沿海塑料球层将由共氨氧化菌 Nitrospira 主导，并成为氨氧化和 N2O 产生的热点。
