High concentrations of bioavailable heavy metals impact freshwater sediment microbial communities

Abstract

Heavy metal concentrations within freshwater systems can increase as a result of anthropogenic inputs, which in turn can influence microbial community composition and community function. In this study, lake sediments collected from two historically heavy metal impacted geographical regions [Poyang Lake, People's Republic of China (PRC), and sites adjacent to the Muskegon Watershed, MI (USA)] were analyzed for total and available heavy metals (Cd, Cr, Cu, Pb, and Zn), as well as microbial community structure using highthroughput sequencing technology. In PRC tributaries leading into Poyang Lake, Zn was found to be the most available metal species. In USA sites, available Cd was higher in Mona Lake sites than alternate USA sites. In both regions, results indicate a weak influence of metals on microbial alpha and beta diversity, but strong positive and negative correlations of available heavy metals with specific taxonomic groups of bacteria and archaea. Further, individual metal species impacted microbial groups and operational taxonomic units differently, suggesting that individual metal species are important in determining which microbial groups and species prevail under heavy metal stress, particularly in the case of bioavailable metals. In PRC, several taxonomic groups were correlated positively with Zn, including Actinobacteria, Bacteroidetes, Proteobacteria, and Verrucomicrobia. Geobacter and Pedosphaerales were both correlated positively to Cr in the same sites, while other correlations with microbial groups were negative. In sites from the USA, Deltaproteobacteria were correlated positively with Cd, while Betaproteobacteria were negatively correlated, suggesting that Cd resistance may differ at the level of Class within Proteobacteria. This study highlights the importance of analyzing available metals when examining the impact of this disturbance on microbial community structure within aquatic sediments.

Taxon-Function Decoupling as an Adaptive Signature of Lake Microbial Metacommunities Under a Chronic Polymetallic Pollution Gradient

“…One of those studies reported the impact of an extreme poly-metallic gradient (including arsenic) on the diversity and distribution of arsenic-related genes in river waters (Desoeuvre et al, 2016 ). Other studies on AMD polluted freshwater sediments (Sánchez-Andrea et al, 2011 ; Jackson et al, 2015 ; Jie et al, 2016 ; Ni et al, 2016 ) showed the dominance of Proteobacteria in microbial communities as well as community specialization. In lake sediments exposed to AMD gradients, the effects of different metals on specific microbes and microbial activities were correlated with their respective chemical properties.…”

Metal contaminations impact archaeal community composition, abundance and function in remote alpine lakes

“…). Metal inputs (e.g., as a result of industrial activities) can have strong effects over the abundance of microbial clades (Rastogi et al ., ; Ma et al ., ; Ni et al ., ), which potentially can alter nutrient cycling (Niemeyer et al ., ; Ni et al ., ). Our results were in line with previous findings (Gough and Stahl, ; Niemeyer et al ., ) and revealed a recurrent decrease of 16S rRNA copy numbers for all the enumerated microbial groups in those lakes with metal contamination (Fig.…”

Monitoring the Activated Sludge Activities Affected by Industrial Toxins via an Early-Warning System Based on the Relative Oxygen Uptake Rate (ROUR) Index

“…Different experimental system might explain this discrepancy. Most of the previous studies used an enclosed system to test the oxygen consumption after 10 minute-aeration [42,61], which was easy in operation but hardly applied for online OUR monitoring as the wastewater samples required sequential collection. In contrast, our laboratory monitoring system used the batch reactor by injecting wastewater and the activated sludge simultaneously and cultivating the mixture with different HRT (ranging from 1 to 60 min, 10 min for the dose-effect of PTEs), consequently resulting in relative longer exposure of the activated sludge to the toxic substances and lowering the EC50.…”

“…In the present study, the EC 50 of Zn 2+ for the activated sludge (13.40 mg/L) was similar with those obtained from individual bioreporter strains, e.g., 10.9 mg/L by Psychrobacter sp. bioreporters [24] and 16 mg/L by Pseudomonas Shk1 bioreporters [42], but much lower than other previous studies on the activated sludge (around 50 to 60 mg/L) [42,61]. Similarly, the EC 50 of Ni 2+ and phenol in the present study was also lower than previous studies on the activated sludge (21-190 mg/L for Ni 2+ and 416-608 mg/L for phenol) [48,62,63] or by Pseudomonas Shk1 bioreporters (96 mg/L for Ni 2+ and 482 mg/L for phenol) [64,65].…”

“…The oxygen uptake rate (OUR) is a theoretical indicator for characterizing the activated sludge activities, representing the in situ changes of microbial activities in removing pollutants [41][42][43]. The OUR has been used for several cases of toxicity assessment like organic compounds, PTEs, and complex wastewater [14,44].…”