Dynamics of coastal bacterial community average ribosomal RNA operon copy number reflect its response and sensitivity to ammonium and phosphate

Tianjiao Dai; Yanan Zhao; Daliang Ning; Bei Huang; Qinglin Mu; Yunfeng Yang; Donghui Wen

doi:10.1016/j.envpol.2020.113971

Dynamics of coastal bacterial community average ribosomal RNA operon copy number reflect its response and sensitivity to ammonium and phosphate

Environ Pollut. 2020 May:260:113971. doi: 10.1016/j.envpol.2020.113971. Epub 2020 Jan 11.

Authors

Tianjiao Dai¹, Yanan Zhao², Daliang Ning³, Bei Huang⁴, Qinglin Mu⁴, Yunfeng Yang⁵, Donghui Wen⁶

Affiliations

¹ College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China; State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China.
² College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China.
³ State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China; Institute for Environmental Genomics, Department of Microbiology and Plant Biology, And School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, OK, USA; Consolidated Core Laboratory, University of Oklahoma, Norman, OK, USA.
⁴ Zhejiang Provincial Zhoushan Marine Ecological Environmental Monitoring Station, Zhoushan, 316021, China.
⁵ State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China.
⁶ College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China. Electronic address: dhwen@pku.edu.cn.

PMID: 31972418
DOI: 10.1016/j.envpol.2020.113971

Abstract

The nutrient-rich effluent from wastewater treatment plants (WWTPs) constitutes a significant disturbance to coastal microbial communities, which in turn affect ecosystem functioning. However, little is known about how such disturbance could affect the community's stability, an important knowledge gap for predicting community response to future disturbances. Here, we examined dynamics of coastal sediment microbial communities with and without a history of WWTP's disturbances (named H1 and H0 hereafter) after simulated nutrient input loading at the low level (5 mg L^-1 NH₄⁺-N and 0.5 mg L^-1 PO₄^3--P) or high level (50 mg L^-1 NH₄⁺-N and 5.0 mg L^-1 PO₄^3--P) for 28 days. H0 community was highly sensitive to both low and high nutrient loading, showing a faster community turnover than H1 community. In contrast, H1 community was more efficient in nutrient removal. To explain it, we found that H1 community constituted more abundant and diversified r-strategists, known to be copiotrophic and fast in growth and reproduction, than H0 community. As nutrient was gradually consumed, both communities showed a succession of decreasing r-strategists. Accordingly, there was a decrease in community average ribosomal RNA operon (rrn) copy number, a recently established functional trait of r-strategists. Remarkably, the average rrn copy number of H0 communities was strongly correlated with NH₄⁺-N (R² = 0.515, P = 0.009 for low nutrient loading; R² = 0.749, P = 0.001 for high nutrient loading) and PO₄^3--P (R² = 0.378, P = 0.034 for low nutrient loading; R² = 0.772, P = 0.001 for high nutrient loading) concentrations, while that of H1 communities was only correlated with NH₄⁺-N at high nutrient loading (R² = 0.864, P = 0.001). Our results reveal the potential of using rrn copy number to evaluate the community sensitivity to nutrient disturbances, but community's historical contingency need to be taken in account.

Keywords: Bacterial community; Nutrients loading; Sensitivity; Wastewater disposal; rRNA operon copy number.

MeSH terms

Ammonium Compounds*
DNA Copy Number Variations
Environmental Monitoring*
Operon
Phosphates*
RNA, Ribosomal
Water Microbiology*
Water Pollution

Substances

Ammonium Compounds
Phosphates
RNA, Ribosomal