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

Xiaoying Mu; Xiaoyang Lv; Wei Liu; Changhao Qiu; Yu Ma; Songhe Zhang; Erik Jeppesen

doi:10.1016/j.envpol.2020.115203

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

Environ Pollut. 2020 Nov;266(Pt 2):115203. doi: 10.1016/j.envpol.2020.115203. Epub 2020 Jul 10.

Authors

Xiaoying Mu¹, Xiaoyang Lv¹, Wei Liu², Changhao Qiu¹, Yu Ma¹, Songhe Zhang³, Erik Jeppesen⁴

Affiliations

¹ Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing, 210098, PR China.
² Department of Bioscience, Aarhus University, Silkeborg, Denmark.
³ Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing, 210098, PR China. Electronic address: shzhang@hhu.edu.cn.
⁴ Department of Bioscience, Aarhus University, Silkeborg, Denmark; Sino-Danish Centre for Education and Research, Beijing, 100049, PR China; Limnology Laboratory, Department of Biological Sciences and Centre for Ecosystem Research and Implementation, Middle East Technical University, Ankara, Turkey.

PMID: 32711247
DOI: 10.1016/j.envpol.2020.115203

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. 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^-1¹⁵N 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.

Keywords: Ammonium; Biofilms; Denitrification; Nitrification; Nitrogen cycle-related genes; Submersed macrophyte.

MeSH terms

Biofilms
Denitrification
Metagenomics
Nitrification
Nitrogen / analysis*
Wastewater
Wetlands*

Substances

Waste Water
Nitrogen