The mechanisms behind nitrogen removal by the submersed macrophyte-biofilm complex in wetlands remain to be fully elucidated. This study investigated the role of Myriophyllum spicatum and the biofilm on their leaves in nitrogen removal in mesocosm experiments. ¹⁵N tracking showed that 61.9% and 30% of the ¹⁵N, respectively, was removed from the system and assimilated by the macrophyte-biofilm complex after loading with 5.4 mg L^{−1 15}N labelled NH₄⁺ for 17 days. Nitrogen budget results showed that about 0.2%, 0.2% and 3.6% of the nitrogen were emitted as water-, HCl- and NaOH-soluble nitrogen-gas species, respectively. Bacteria (76.7–91.8%) were the predominant domain in all samples, followed by eukaryotes (8.0–23.0%), archaea and viruses. Network analyses showed that there were positive- and negative-correlative relationships among nitrogen-cycling genes and nitrifiers and denitrifiers. Our data highlight the important role of biofilm on submersed macrophytes for nitrogen removal.

湿地大型植物-生物膜复合物在湿地中除氮的机理尚待充分阐明。这项研究调查的作用，狐尾藻和脱氮围隔实验上的叶子生物膜。¹⁵ N示踪表明，分别从系统中除去了¹⁵ N中的61.9％和30％，并在装载5.4 mg L ^{-1 15} N标记的NH ₄ ⁺后被大型植物生物膜复合物吸收。持续17天。氮预算结果显示，分别以水，HCl和NaOH溶解性氮气形式排放了约0.2％，0.2％和3.6％的氮。细菌（76.7–91.8％）是所有样品中的主要区域，其次是真核生物（8.0–23.0％），古细菌和病毒。网络分析表明，氮循环基因与硝化剂和反硝化剂之间存在正相关和负相关。我们的数据突显了生物膜在沉水大型植物中对脱氮的重要作用。