Changes in Stoichiometry of Carbon and Nitrogen Trigger Transition in the States of Aquatic Microbiota in Full-Scale Constructed Wetlands

Abstract

Constructed wetlands (CWs) are broadly adopted technology for ecosystem service and various types of wastewater treatment. However, their unstable and unpredictable performance hindered their application and promotion. Transitions in microbial community are strong indicators of treatment performance of CWs. The unstable treatment of perturbed CWs is reflected not only in water quality indices but also in altered aquatic microbial composition. A comprehensive analysis was performed to elucidate the multistable microbial communities and their relationship nutrient concentration. Changes in environmental gradients modulate the strength of microbiota feedbacks and, together with molecular ecological networks, provide positive feedbacks for the generation and maintenance of alternative states. The community succession responding to the concentration of carbon and nitrogen was manipulated by stochastic instead of deterministic processes. The relative abundance of stochastic processes increased from state A (73.34%) to state B (89.28%). Furthermore, the high proportion of stochastic events in microbial communities easily trigger the transition to alternative states. To summarize, this study proposes a better understanding of the hypothesis of alternative stable states in the response of ecosystems to nutrient concentration, which could provide a strategy for the stoichiometric regulation of carbon and nitrogen changes along from the inlet to outlet in CWs.

Linking ecological niches to bacterial community structure and assembly in polluted urban aquatic ecosystems

“…® Soil DNA Kit (Omega Bio-tek, Norcross, GA, U.S.) according to manufacturer's protocols. In contrast, the microorganism samples concentrated on the filter membranes were initially immersed in the DNA extraction solution to resuspend the microorganisms prior to subsequent DNA extraction (De Lorenzi et al, 2022;Tong et al, 2022). The V4-V5 region of the bacteria 16S ribosomal RNA gene were amplified by PCR using primers 515F (5′-GTGCCAGCMGCCGCGG-3′) and 907R (5'-CCGTCAATTCMTTTRAGTTT-3′).…”