Differentiation of nitrogen and microbial community in the littoral and limnetic sediments of a large shallow eutrophic lake (Chaohu Lake, China)
Nitrogen (N) is one of the major elements causing eutrophication in freshwater lakes, and the N cycle is mainly driven by microorganisms. Lake littoral zones are found to be “hotspots” for N removal from both the basin and receiving waters. However, the environmental factors that drive the distribution of microorganisms are diverse and unclear. Here, we examined the differentiation of nitrogen and microbial community between the littoral and limnetic sediments to explore their interactions.
Materials and methods
Sediment samples were collected in the littoral and limnetic zones of Chaohu Lake in winter (ca. 7 °C) and autumn (ca. 22 °C). Abundances of the bacterial and archaeal genes amoA (ammoxidation), nirS and nirK (denitrification), hzsB (anaerobic ammonium oxidation; anammox), and nrfA (dissimilatory nitrate reduction to ammonium; DNRA) were measured via quantitative real-time polymerase chain reaction (qPCR). Clone libraries were constructed for further phylogenetic analysis to study the community composition.
Results and discussion
We observed significant higher concentration values in terms of sedimentary NH4+-N and NO3−-N in the limnetic zone than littoral zone (p < 0.05; n = 12). In general, abundance values of the above six genes in the littoral zone were all higher than those in the limnetic zone, while higher in winter (7 °C) than in autumn (22 °C) (p < 0.05; n = 6). The spatial heterogeneity had the most significant effect on the distribution of ammonia-oxidizing archaea (AOA) and anammox bacteria abundance. Both temporal (temperature) and spatial heterogeneity affected the abundance of ammonia-oxidizing bacteria (AOB). The variation in the abundance of denitrifying bacteria and DNRA bacteria mainly reflected the temporal (temperature) heterogeneity.
The six N-cycle-related microorganisms were affected by different environmental factors and presented different distribution patterns. The lower nitrogen content and the higher microbial abundance and diversity showed that the littoral zone was the “hotspot” of N-cycling-related microorganisms in a large, eutrophic, and turbid lake. It is suggested that increasing the area and restoring the ecological function of the littoral zone was effective and significant in eutrophic lake management.
KeywordsAbundance Eutrophic freshwater lake Littoral zone Microbial N-cycle Sediment
This research is financially supported by the Major National Water Pollution Control and Management Project (2014ZX07405-003 and 2017ZX07201004-002), National Natural Science Foundation of China (No. 41671471, 41322012 and 51278487), Strategic Priority Research Program of the Chinese Academy of Sciences (XDB15020303), National Key R&D Program (2016YFA0602303), Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (2017BT01Z176), special fund from the State Key Joint Laboratory of Environment Simulation and Pollution Control (Research Center for Eco-environmental Sciences, Chinese Academy of Sciences) (18Z02ESPCR), Open Research Fund of Key Laboratory of Drinking Water Science and Technology, Chinese Academy of Sciences (16Z03KLDWST), CAS/SAFEA International Partnership Program for Creative Research Teams, and Jiaxing Science and Technology Project (2015AY23008). The author Guibing Zhu gratefully acknowledges the support of a Humboldt Research Fellowship (1152633), and Program of the Youth Innovation Promotion Association (CAS).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
- Bruesewitz DA, Tank JL, Hamilton SK (2012) Incorporating spatial variation of nitrification and denitrification rates into whole-lake nitrogen dynamics. J Geophys Res Biogeo 117:G00N07Google Scholar
- Haworth EY, Lund JWG, Tutin W (1984) Lake sediments and environmental history. J Ecol 73(2):713Google Scholar
- Juretschko S, Timmermann G, Schmid M, Schleifer KH, Pommerening-Roser A, Koops HP, Wagner M (1998) Combined molecular and conventional analyses of nitrifying bacterium diversity in activated sludge: Nitrosococcus mobilis and Nitrospira-like bacteria as dominant populations. Appl Environ Microbiol 64:3042–3051Google Scholar
- Megonigal JP, Mines ME, Visscher PT (2005) Linkages to trace gases and aerobic processes. Biogeochemistry 8:350–362Google Scholar
- Purkhold U, Pommerening-Röser A, Juretschko S, Schmid MC, Koops HP, Wagner M (2000) Phylogeny of all recognized species of ammonia oxidizer based on comparative 16S rRNA and amoA sequence analysis: implications formolecular diversity surveys. Appl Environ Microbiol 66:5368–5382CrossRefGoogle Scholar
- Saitou N, Nei M (1987) The neighbor-joining method: a new method for reconstructing phylogenetic trees. Mol Biol Evol 4:406–425Google Scholar
- Tiedje JM (1988) Ecology of denitrification and dissimilatory nitrate reduction to ammonium. In: John W (ed) Methods of soil analysis. John Wiley and Sons, New York, pp 179–244Google Scholar
- Xie BK (2016) Study on the process characteristics and influence factors of disssimilatory nitrate reduction to ammonium by strain desulfovibrio sp. CMX. Dalian University of Technology (in Chinese)Google Scholar
- Yang GS, Ma RH, Zhang L, Jiang JH, Yao SC, Zhang M, Zeng HA (2010) Lake status, major problems and protection strategy in China. J Lake Sci 22:799–810 (in Chinese) Google Scholar
- Yin CQ (1999) The ecological function, protection and utilization of land/inland water ecotones. J Environ Sci 11:120–124Google Scholar
- Yin FC (2011) Study on the evaluation and control strategy of eutrophication in Lake Chaohu. Jia WL, Beijing, pp 35–36Google Scholar
- Zhao SY, Zhuang LJ, Wang C, Li YF, Wang SY, Zhu GB (2017) High-throughput analysis of anammox bacteria in wetland and dryland soils along the altitudinal gradient in Qinghai-Tibet Plateau. Microbiologyopen 7(2):e00556Google Scholar
- Zhou LL, Wang SY, Zou YX, Xia C, Zhu GB (2015) Species, abundance and function of ammonia-oxidizing archaea in inland waters across China. Sci Rep 5:159–169Google Scholar
- Zumft WG (1997) Cell biology and molecular basis of denitrification. Microbiol Mol Biol R 61:533–616Google Scholar