Biofilms attached to Myriophyllum spicatum play a dominant role in nitrogen removal in constructed wetland mesocosms with submersed macrophytes: Evidence from N-15 tracking, nitrogen budgets and metagenomics analyses


Mu X., Lv X., Liu W., Qiu C., Ma Y., Zhang S., ...More

ENVIRONMENTAL POLLUTION, vol.266, 2020 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 266
  • Publication Date: 2020
  • Doi Number: 10.1016/j.envpol.2020.115203
  • Title of Journal : ENVIRONMENTAL POLLUTION
  • Keywords: Submersed macrophyte, Biofilms, Ammonium, Nitrification, Denitrification, Nitrogen cycle-related genes, COMMUNITY STRUCTURE, STABLE-ISOTOPES, FOOD WEBS, DENITRIFICATION, GENES, NITRIFICATION, EFFLUENTS, SEDIMENT, AERATION, BACTERIA

Abstract

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. N-15 tracking showed that 61.9% and 30% of the N-15, respectively, was removed from the system and assimilated by the macrophyte-biofilm complex after loading with 5.4 mg L-1 N-15 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. (C) 2020 Elsevier Ltd. All rights reserved.