Myriophyllum elatinoides growth and rhizosphere bacterial community structure under different nitrogen concentrations in swine wastewater
Graphical abstract
Introduction
With the rapid development of livestock and poultry breeding, livestock wastewater has become a severe environmental contaminant, which affects water bodies worldwide (Hooda et al., 2000, Wang et al., 2016a). Swine wastewater contains a high concentration of ammonia nitrogen (NH4+) (Ye et al., 2010, Huang et al., 2016), which cannot be effectively removed at a large scale without the use of wastewater disposal technology (Xu et al., 2015). Constructed wetlands (CWs) are widely regarded as a low cost, low energy, simple operation and high efficiency technology for treating various wastewater (Vymazal, 2009, Filali et al., 2017, Hernandez-Crespo et al., 2017). Plants are important components of CWs for nitrogen (N) and phosphorus (P) removal due to their strong absorption capacity (Li et al., 2009, Zhang et al., 2011). In addition, plant root exudates and secreted oxygen strongly influence rhizosphere microbes (Bever et al., 2010). The rhizosphere often has higher microbial activity than non-rhizosphere soil and these microbes are involved in the processing of organics and nutrients (Wang et al., 2008). Some researchers have reported that rhizosphere microbes play an essential role in reducing the concentrations of pollutants (Marschner et al., 2011, Bell et al., 2014). Rhizosphere microbial community structure often varies with plant species (Bell et al., 2015).
Myriophyllum elatinoides is one of the best floating plants for removing high concentrations of N and P from swine wastewater due to its tolerance of high nutrient conditions and ability to improve sediment microbial activity (Li et al., 2018, Li et al., 2019). However, the responses of M. elatinoides rhizosphere microbes to different N concentrations, and the effect on N removal from swine wastewater, are still unclear. Moreover, patterns of M. elatinoides growth and the dynamics of N distribution in the plant’s organs under varying N concentrations are not known. Understanding the growth characteristics of M. elatinoides and mechanisms of microbial N removal can inform the management and application of M. elatinoides in treating swine wastewater.
In this study, surface flow constructed wetlands (SFCWs) planted with M. elatinoides were created to treat swine wastewater with five different levels of N concentration. The aims of this study were 1) to examine M. elatinoides growth characteristics and biomass under different N concentrations in swine wastewater; 2) to investigate the community structure of rhizosphere microbes; 3) to determine the N removal mechanisms and understand the interactions between environmental factors and rhizosphere microbes. These results will increase the understanding of the N removal mechanism for treatment different N concentrations swine wastewater in M. elatinoides SFCWs and provide a plant management strategy for M. elatinoide.
Section snippets
Experimental set-up
SFCWs were constructed at the Changsha Research Station for Agricultural and Environmental Monitoring, Hunan Province, China (28°30′N, 113°18′E). The study was conducted from September 1 to November 3, 2017. During the experimental period, average temperature and average precipitation were 26 °C and 23.6 mm, respectively. Fifteen concrete ponds (0.8 m long by 0.5 m wide by 0.4 m deep) were used as SFCWs, and filled to about 0.1 m depth with paddy soil. An inlet was placed at the surface of the
Plant growth under different N concentrations
Fig. 1 shows the fitted growth curve for M. elatinoides under different N concentrations (R2 > 0.94) (Table 1), which shows the variation in biomass over 63 days. Myriophyllum elatinoides growth tended to stabilize at 49 days in all treatments, suggesting that M. elatinoides could be harvested for nutrient removal at this time. Some studies have reported that harvesting plants at regular intervals can improve overall nutrient removal in CWs (Wang et al., 2015, Zheng et al., 2015). The biomass
Conclusions
M. elatinoides SFCWs were studied to determine plant growth and factors driving rhizosphere bacterial community structure under different N concentrations. High N concentrations lead to decreases in biomass and RGR. N concentrations in the roots, stems, and leaves were higher in T2 than those in other treatments. Sequencing showed that the highest bacterial diversity was found in treatment T3. Bacterial community structure changed under different N concentrations. pH was a key factor in shaping
Author contribution
Xi Li design and performed the experiment, analyze the experimental data, and write this manuscript.
Yuyuan Li, Yong Li and Jinshui Wu guide the experiment and revise this manuscript.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
This study was financially supported by the National Key Research and Development Program of China (2018YFD0800100), the Key Science and Technology Project of Henan Province, China (161100310600), and the Natural Science Foundation of Hunan Province, China (2018JJ3581). We thank Public Service Technology Center, Institute of Subtropical Agriculture, and the Chinese Academy of Sciences for providing experimental platform.
References (48)
- et al.
Characterisation of the soil bacterial community structure and composition of natural and constructed wetlands
Sci. Total Environ.
(2014) - et al.
Treatment of domestic wastewater by subsurface flow constructed wetlands in Jordan
Desalination
(2003) - et al.
Physiological plastic responses to acute NH4+-N toxicity in Myriophyllum spicatum L. cultured in high and low nutrient conditions
Environ. Exp. Bot.
(2016) - et al.
Plant nitrogen uptake drives rhizosphere bacterial community assembly during plant growth
Soil Biol. Biochem.
(2015) - et al.
Rooting theories of plant community ecology in microbial interactions
Trends Ecol. Evol.
(2010) - et al.
Effects of plant biomass on bacterial community structure in constructed wetlands used for tertiary wastewater treatment
Ecol. Eng.
(2015) - et al.
Effects of root organic exudates on rhizosphere microbes and nutrient removal in the constructed wetlands
Ecol. Eng.
(2016) - et al.
Microbial community succession and pollutants removal of a novel carriers enhanced duckweed treatment system for rural wastewater in Dianchi Lake basin
Bioresour. Technol.
(2019) - et al.
Plant effects on microbial assemblages and remediation of acidic coal pile run off in mesocosm treatment wetlands
Ecol. Eng.
(2004) - et al.
Review: mechanisms of ammonium toxicity and the quest for tolerance
Plant Sci.
(2016)
High-frequency measurement of N2O emissions from a full-scale vertical subsurface flow constructed wetland
Ecol. Eng.
A review of water quality concerns in livestock farming areas
Sci. Total Environ.
Performance of surface and subsurface flow constructed wetlands treating eutrophic waters
Sci. Total Environ.
Simultaneous removal of ammonia nitrogen and recovery of phosphate from swine wastewater by struvite electrochemical precipitation and recycling technology
J. Clean. Prod.
Enhanced nitrogen and phosphorus removal from eutrophic lake water by Ipomoea aquatica with low-energy ion implantation
Water Res.
Comparison of four aquatic plant treatment systems for nutrient removal from eutrophied water
Bioresour. Technol.
Seasonality distribution of the abundance and activity of nitrification and denitrification microorganisms in sediments of surface flow constructed wetlands planted with Myriophyllum elatinoides during swine wastewater treatment
Bioresour. Technol.
Enhanced nitrogen removal and quantitative analysis of removal mechanism in multistage surface flow constructed wetlands for the large-scale treatment of swine wastewater
J. Environ. Manage.
Rhizosphere interactions between microorganisms and plants govern iron and phosphorus acquisition along the root axis e model and research methods
Soil Biol. Biochem.
Degradation of organophosphate esters in sewage sludge: effects of aerobic/anaerobic treatments and bacterial community compositions
Bioresour. Technol.
Nitrogen removal in a two-chambered microbial fuel cell: establishment of a nitrifying-denitrifying microbial community on an intermittent aerated cathode
Chem. Eng. J.
Components of floating emergent macrophyte treatment wetlands influencing removal of stormwater pollutants
Ecol. Eng.
Microbial community composition and activity controls phosphorus transformation in rhizosphere soils of the Yeyahu Wetland in Beijing
China. Sci. Total Environ.
The use of constructed wetlands with horizontal sub-surface flow for various types of wastewater
Ecol. Eng.
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