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Silver nanomaterials (Ag NMs) have been used in a variety of commercial products to take advantage of their antimicrobial properties. However, there are concerns that these AgNMs can be released during/after use and enter wastewater streams, potentially impacting aquatic systems or accumulating in wastewater biosolids. Biosolids, which are a residual of wastewater treatment processes, have been found to contain AgNMs and are frequently used as agricultural fertilizer. Since the function of soil microbial communities is imperative to nutrient cycling and agricultural productivity, it is important to characterize and assess the effects that silver nanomaterials could have in agricultural soils. In this study agricultural soil was amended with pristine engineered (PVP-coated or uncoated AgNMs), aged silver (sulphidized or released from textiles) nanomaterials, and ionic silver to determine the fate and toxicity over the course of three months. Exposures were carried out at various environmentally relevant concentrations (1 and 10 mg Ag/kg soil) representing between 30 to over 800 years of equivalent biosolid loadings. Over thirteen different methodologies and measures were used throughout this study to assess for potential effects of the silver nanomaterials on soil, including microbial community composition, average well colour development (AWCD) and enzymatic activity. Overall, the AgNM exposures did not exhibit significant toxic effects to the soil microbial communities in terms of density, activity, function and diversity. However, the positive ionic silver treatment (100 mg Ag/kg soil) resulted in suppression to microbial activity while also resulting in significantly higher populations of Frankia alni (nitrogen-fixer) and Arenimonas malthae (phytopathogen) as compared to the negative control (p < 0.05, Tukey HSD) which warrants further investigation.

The discharge from food production greenhouses (greenhouse effluent) contains high nutrient and salt concentrations, which, if directly released, can have adverse effects on the environment. Wood-chip bioreactors are increasingly popular passive water treatment systems favoured for their economical denitrification in treating agricultural field tile drainage. Microbial communities are central to denitrification; however little is known about the maturation of microbial communities in wood-chip bioreactors treating greenhouse effluents. In this study, multiple subsurface flow wood-chip bioreactors, each vegetated with a different plant species, together with an unplanted unit, received synthetic greenhouse effluent with elevated nitrate concentrations. The hybrid bioreactors were operated for over 2 years, during which time water samples were collected from the inlet, outlet and within the reactors. The increasing denitrification rate in the bioreactor planted with Typha angustifolia (narrowleaf cattail) correlated with increasing microbial activity and metabolic richness, measured by the carbon utilization patterns in Biolog® EcoPlates. Increased denitrifying gene (nirS) copies (determined by quantitative polymerase chain reaction, qPCR), and near-complete nitrate removal were observed in the T. angustifolia and unplanted reactors after 16 and 23 months of operation respectively. The findings suggested that an acclimation period of at least one year can be expected in unseeded bioreactors planted with T. angustifolia, while bioreactors without vegetation may require a longer time to maximize their denitrification capacity. These results are important for the design and operation of wood-chip bioreactors, which are expected to be more commonly applied in the future.

The microbial characteristics of four vegetated and one unplanted wood-chip bioreactors treating greenhouse effluent were investigated in a continuous experiment operated for over 2.5 years. The bioreactors were designed to reduce nitrate concentrations via naturally induced microbial denitrification. The vegetation type and reactor depth were both found to be significant factors in defining the mixed microbial activity. However, a consistent correlation between the abundance of the denitrifying communities and reactor depth could not be found across all reactors. The media samples from the unit planted with Typha angustifolia displayed higher microbial activities compared with the other reactors. This plant&rsquo, s root-associated bacteria also demonstrated the greatest copies of the denitrifying genes nirK and nosZ. The most abundant denitrifier communities and those encoding the nosZ gene were found in the unplanted reactor, followed by the T. angustifolia unit. The T. angustifolia reactor demonstrated greater microbial activity and denitrification capacity at the depth of 20 cm, while the greatest denitrification capacity in the unplanted reactor was found at the depth of 60 cm. These findings indicated the importance of the T. angustifolia rhizosphere to support microbial community establishment and growth in the vicinity of the plant&rsquo, s roots, although those populations may eventually develop in an unplanted environment.

The objective of this research was to study the differences in microbial community metabolic function in planted and unplanted saturated constructed wetland mesocosm systems with five different wetland plant species, Typha latifolia, Phragmites australis, Iris pseudacorus, Berula erecta and Juncus effusus treating the pesticides imazalil and tebuconazole. Community level physiological profiling (CLPP) was used to determine the microbial community metabolic function from each mesocosm. Microbial activity and metabolic richness were in general not differentiated by pesticides presence. Significantly lower values in comparison with a non-pesticide control were only found in the Iris mesocosms exposed to imazalil and tebuconazole and in the Berula mesocosms exposed to tebuconazole during winter. Planted mesocosms had different microbial community carbon source utilization patterns in comparison to the unplanted mesocosms. In comparison to pesticide presence, plant species had a larger effect on differentiating the microbial community carbon source utilization patterns. Seasonal effects on carbon source utilization patterns were observed for both planted and unplanted mesocosms. In summer, microbial activity and metabolic richness were negatively correlated with TN, NH4+-N, TP concentration and pH in the control group, but not in the pesticide treatment groups, again suggesting a microbial community functional shift in the presence of pesticides. The main factors driving microbial community activity and functional diversity were plant species and season, while carbon source utilization revealed some pesticide adaptation in the summer period.

The aim of the present study was to elucidate the microbial community metabolic profiles in saturated constructed wetland (CW) mesocosms planted with five different wetland plant species fed with water individually spiked with 100 μg L-1 ibuprofen or iohexol. Community-level physiological profiling (CLPP) using Biolog Ecoplates was performed and coupled with the assessment of water quality parameters (water temperature, pH, DO and TOC, TN, NH4-N, PO4-P removal efficiency). The microbial community metabolic profiles (microbial acitivity, richness, and carbon source utilization), as well as the water quality parameters revelead similar trends among the control mesocosms and the mescocosms fed with water spiked with iohexol and ibuprofen. Significant differences were observed between the planted and unplanted mesocosms and between seasons (summer and winter) within each of the feeding lines (control, iohexol or ibuprofen). The microbial community metabolic profiles in the saturated CW were shaped by plant presence and plant species, while no impact of iohexol and ibuprofen presence was noticed at the 100 μg L-1. In addition, the microbial activity and richness were generally higher in planted mesocosms than in the unplanted systems in the summer. For the first time, a positive correlation between iohexol removal and the microbial community metabolic profiles (activity, richness and amines and amides utilization in summer, and carbohydrates utilization in winter) in the saturated mesocosms was observed. Biodegradation was a main driver for iohexol and ibuprofen removal. Putrescine utilization in the summer and D-cellobiose, D,L-alpha-glycerol phosphate in winter were linked with the metabolic processing of iohexol, while glycogen in summer and L-phenylalanine, Glycyl-L-glutamic acid in winter linked with the ibuprofen removal efficiency in the saturated CW.

Silver nanoparticles (AgNPs) are increasingly used as an antimicrobial agent in various consumer products. Silver release from these products occurs during use, washing and disposal at varying rates, into the wastewater system and eventually into aquatic ecosystems. Constructed wetlands (wetlands designed for water pollution control) represent a unique type of water treatment system which are beginning to receive growing amounts of influent AgNP loadings. In order to examine potential impacts to the health and ongoing utility of constructed wetlands we evaluated the susceptibility and the developed resistence of constructed wetland microbial communities to two types of AgNPs (citrate and polyvinylpyrrolidone (PVP)-coated), and ionic Ag (Ag+). Microcosms representing an unplanted batch-fed subsurface flow constructed wetland were exposed to an AgNP contaminated (100 mu g/l) simulated wastewater for 28 days. Experiments were triplicated and included unexposed controls. Analysis of total Ag in the interstitial water and biofilm matrix via inductively coupled plasma mass-spectrometry (ICP-MS) revealed the majority (>98%) of AgNPs partitioned from the interstitial water and accumulated in the biofilm and presumably the sediment matrix. No significant alteration to the microbial community function (assessed via community-level physiological profiling, CLPP) or structure (using denaturing gradient gel electrophoresis, DGGE) was observed following the initial 28 day exposure. Subsequent ex-situ dose-response testing over a wide concentration range (0-5 mu g/l) provided some evidence for increased resistance to Ag toxicity in the previously exposed microbial communities when compared to the controls. The ex-situ evaluated susceptibility of the microbial communities to AgNPs varied between treatments with significant reductions in catabolic activity observed at 0.5 mg/l for ionic Ag, 1 mg/l for citrate coated AgNPs and 5 mg/l for PVP coated AgNPs. These findings suggest that wetland microbial communities can tolerate and develop resistance to lower levels of in-situ AgNP exposure in a relatively short time, however ex-situ toxicity is observed past certain threshold concentrations and this threshold varies depending on the original form of the AgNP. (C) 2016 Elsevier B.V. All rights reserved. This work was financially supported by the Erasmus Mundus programme IMETE (Ghent University, Belgium) and COST action ES1205. The authors thank Nico Boon for access to the Laboratory of Microbial Ecology and Technology (LabMET) and for fruitful discussions. Support from NSERC in the form of a Discovery and an SPG grant to KPW is gratefully acknowledged. We would also like to thank Tim Lacoere for his help with the molecular techniques, Xiao Yi for help with CLPP and Quenten Denon for the assistance with the PCS analysis.

Both the presence and diversity of plants are integral to the development and functional abilities of microbial communities within constructed wetlands (CWs). The aim of this study was to assess the impacts of different individual and paired plant species combinations on microbial community function in HSSF mesocosm CWs. Experimental systems were quadruplicated and operated as two mesocosms in series planted with Phragmites australis (X) or Phalaris arundinacea (O), giving four possible sequential combinations (XX, XO, OX, OO). Wastewater was loaded each day into position 1 mesocosm with the outflow entering position 2 mesocosm, and the corresponding position 2 mesocosm outflow representing an overall experimental system effluent. The metabolic function of the interstitial-based microbial communities within each of the 16 mesocosm pairs was assessed at a single time point in the spring (May) based on community-level physiological profiles (CLPPs) gathered using Biolog ® EcoPlates. Microbial activity and metabolic richness (number of carbon sources utilised) were found to be higher in position 1 mesocosms compared to position two. Microbial community carbon source utilisation patterns (CSUPs), overall activity and metabolic richness were similar between all mesocosms from position 1—irrespective of plant species. When assessing microbial communities in position 2 of each pairing a greater variety of CSUPs, activities and metabolic richness' could be found suggesting the sequence and choice of plant can alter the microbial community function in the HSSF mesocosms. Of particular interest were the mesocosm/plant species combinations containing Phalaris in the position 2 which led to higher overall microbial activity and richness, distinct carbon source utilisation patterns (CSUPs) and an increased utilisation of specific carbon sources further from the inlet. More specifically the XO pairings ( Phragmites-Phalaris ) seemed to offer the most promising overall microbial function throughout both positions 1 and 2 in series suggesting plant diversity may help enhance microbial community function, and therefore microbial based water treatment capacity. The findings also suggest that the microbial communities associated with each plant species respond differently to factors such as nutrient availability, and although not yet clearly defined, further highlights the potential for improved or tailored water treatment in CWs through selection of specific plant species and combinations. Broader microbial community function or greater activity did not correlate with improved water treatment efficiency in this study. This may have been due to the relatively low contaminant loads utilised, or the limited amount of data collected. Further study across several seasons or with higher contaminant loads is recommended.

We collected over 40 groundwater samples from a per- and polyfluoroalkyl substances (PFAS) impacted legacy fire fighting training area in Canada to develop an in-depth assessment of the relationship between PFAS and in situ microbial communities. Results suggest differential transport of PFAS of differing chain-length and head group. There is also evidence of PFAS degradation, in particular 6:2 FTS degradation. Although PFAS constituents were not major drivers of microbial community structure, the relative abundance of over one hundred individual genera were significantly associated with PFAS chemistry. For example, lineages within the Oxalobacteraceae family had strong negative correlations with PFAS, whilst the Desulfococcus genus has strong positive correlations. Results also suggest a range of genera may have been stimulated at low to mid-range concentrations (e.g., Gordonia and Acidimicrobium), with some genera potentially inhibited at high PFAS concentrations. Any correlations identified need to be further investigated to determine the underlying reasons for observed associations as this is an open field site with the potential for many confounding factors. Positive correlations may ultimately provide important insights related to development of biodegradation technologies for PFAS impacted sites, while negative correlations further improve our understanding of the potential negative effects of PFAS on ecosystem health.

The impacts to microbial function, overall performance and eventual fate were assessed for triclosan (TCL) and sulfamethoxazole (SMX) in intensified (re-circulating) vertical subsurface flow (VSSF) constructed wetlands (CWs). The potential toxicity of each pharmaceutical to the intrinsic microbial communities was first assessed over a wide exposure range (0–1000 μg/l) via an ex-situ dose-response assay to estimate the concentration at which adverse effects were likely to occur. Based on these results an acute (7 day) in-situ exposures (500 μg/l) were then performed and impacts to the mesocosm systems monitored for 1 month via community-level physiological profiling (CLPP) alongside chemical oxygen demand (COD) removal rates and a range of water quality, and hydrological parameters. Despite the clear potential for negative impacts to microbial function from both compounds observed at 100 μg/l in the ex-situ dose-response test, no impacts were observed for the 500 μg/l in-situ exposure in the VSSF mesocosms. COD removal, water chemistry, plant health, and hydrological parameters did not significantly change in response to the in-situ exposure. In terms of fate, the removal efficiency for both TCL and SMX was high (>80%) after 1 h and complete removal (>99.7%) was observed after 168 h. Following the in-situ exposure, and subsequent one month effects-monitoring period, the mesocosms were decommissioned with the media biofilm spatially assessed for organic content as well as TCL and SMX concentrations. TCL and SMX were found to have persisted in the media and demonstrated spatial variation with an overall 2–20% and 5–6% recovered respectively. This suggests that biofilm bound TCL and SMX were biologically degraded in VSSF CWs, however may also accumulate in the biofilm if TCL and SMX are maintained in the influent. These results reinforce the robustness and potential of constructed wetlands for the treatment of pharmaceutical and personal care product (PPCP) contaminated wastewater.

Microorganisms are central to the biogeochemical processes in constructed treatment wetlands. In this study we explored the spatial dynamics of microbial community metabolic function in several different constructed treatment wetland designs at the pilot-scale constructed wetlands of the UFZ Ecotechnology Research Facility in Langenreichenbach, Germany. The constructed wetland designs differed in terms of flow direction, degree of saturation, depth, and intensification. Internal sampling was conducted in April 2013 at different locations along the flow path of each system. The microbial community metabolic function was characterized via community level physiological profiling (CLPP). Microbial community activity (substrate utilization rate) and metabolic richness (number of carbon sources utilize) decreased dramatically with increasing distance along the flow path for most systems. Variation in the metabolic function of microbial communities was observed based on carbon source utilization patterns (CSUPs) and was found to be strongly influenced by system design and sample location within the wetland but not by the presence of plants or depth of media. Analysis of specific carbon source guilds highlighted increased utilization of polymers and carbohydrates in the early stages of all systems, pointing to the establishment of microbial communities optimized to best utilize more easily degradable compounds close to the inlet. Correlations between measures of microbial functionality (activity, richness, and diversity) and turbidity, total organic carbon (TOC), total nitrogen (TN) were observed in horizontal-flow systems but less so in vertical-flow systems. The results presented provide useful insight into the spatial dynamics of microbial community function in constructed wetlands. Potential opportunities for system optimization, based on the results of this study, are provided.

Microbial degradation is an important pathway during the removal of pharmaceuticals in constructed wetlands (CWs). However, the effects of CW design, plant presence, and different plant species on the microbial community in CWs have not been fully explored. This study aims to investigate the microbial community metabolic function of different types of CWs used to treat ibuprofen via community-level physiological profiling (CLPP) analysis. We studied the interactions between three CW designs (unsaturated, saturated and aerated) and six types of mesocosms (one unplanted and five planted, with Juncus, Typha, Berula, Phragmites and Iris) treating synthetic wastewater. Results show that the microbial activity and metabolic richness found in the interstitial water and biofilm of the unsaturated designs were lower than those of the saturated and aerated designs. Compared to other CW designs, the aerated mesocosms had the highest microbial activity and metabolic richness in the interstitial water, but similar levels of biofilm microbial activity and metabolic richness to the saturated mesocosms. In all three designs, biofilm microbial metabolic richness was significantly higher (p

The objective of this study was to investigate if the catabolic capabilities (the overall ability to utilize a wide range of carbon sources) and catabolic profiles (the overall pattern of carbon source usage based on the carbon source types and relative usage extent) of microbial communities in free-floating plant treatment wetlands differ based on the presence or combination of different plant species. Free Floating-plant treatment wetland mesocosms were established using four different plant species: Limnobium laevigatum (L), Salvinia molesta (S), Eichhornia crassipes (E), and Pistia stratiotes (P). Mesocosms were either arranged as a monoculture (one plant species), biculture (two different plant species; all possible pairings), or quadricultures (one of each plant species). Mesocosms were fed twice weekly with 20 L of reconstituted wastewater using diluted fish farm sludge effluent. The microbial communities in each mesocosm were assessed after a 4 month operational period using the community level physiological profiling (CLPP) method. It was observed that monoculture wetland systems had different catabolic activities and catabolic richness’ (number of carbon sources utilized) with the following respective trends: (L) > (P) = (S) > (E) and (L) > (E) = (P) > (S). It was also found that the carbon source utilization patterns of the microbial communities from the monoculture mesocosms were distinctly different from each other, and that the polyculture communities were different from the respective monoculture counterparts. These findings further support the hypothesis that plant type and combination plays a critical role in the development of the microbial communities present in treatment wetlands. It was also found that increasing the number of plant species did not, on average, promote the development of microbial communities with a more active and diverse catabolic capability, but rather specific plant selection and plant/plant interactions were important. In comparison to the other plant species E. crassipes had the largest amount of root mass available for microbial community attachment. Observations suggested that this larger root mass translated into E. crassipes having a dominating effect on defining the carbon source utilization patterns of microbial communities from polyculture mesocosms. Although microbial communities from the monoculture mesocosms containing E. crassipes had the lowest activities (on a per unit volume basis), E. crassipes mesocosms generally had the best COD removal rates in either monoculture or polyculture systems, potentially because of the greater amount of root mass available.

The effect of gold nanoparticles (AuNPs) and ciprofloxacin on the catabolism of microbial communities was assessed. This was accomplished through an ex situ methodology designed to give a priori knowledge on the potential for nanoparticles, or other emerging contaminants, to affect the catabolic capabilities of microbial communities in the environment. Microbial communities from a variety of sources were incubated with 31 prespecified carbon sources and either National Institute of Standards and Technology reference material 10-nm AuNPs or ciprofloxacin on 96-well microtiter plates. From the ciprofloxacin study, dose−response curves were generated and exemplified how this method can be used to assess the effect of a toxicant on overall catabolic capabilities of microbial communities. With 10-nm AuNPs at concentrations ranging from 0.01 µg/mL to 0.5 µg/mL, rhizosphere communities from Typha roots were only slightly catabolically inhibited at a single concentration (0.05 µg/mL); no effects were seen on wetland water communities, and a minor positive (i.e., enhanced catabolic capabilities) effect was observed for loamy soil communities. This positive effect might have been because of a thin layer of citrate found on these AuNPs that initiated cometabolism with some of the carbon sources studied. Under the conditions considered, the possible adverse effects of AuNPs on the catabolic capabilities of microbial communities appears to be minimal. Environ Toxicol Chem 2013;33:44–51. © 2013 SETAC

Microbial communities play a vital role in maintaining soil health. A multiphasic approach to assess the effect of pulp and paper mill effluent on both the structure and function of microbial soil communities is taken. Bacterial communities from agricultural soils irrigated with pulp and paper mill effluent were compared to communities form soils irrigated with well water. Samples were taken from fields in the state of Uttarakhand, India, where pulp and paper mill effluent has been used for irrigation for over 25 years. Comparisons of bacterial community structure were conducted using sequencing of the 16S rRNA gene from both isolates and clone libraries attained from the soil. Community-level physiological profiling was used to characterize the functional diversity and catabolic profile of the bacterial communities. The multiphasic approach using both physiological and molecular techniques proved to be a powerful tool in evaluating the soil bacterial community population and population differences therein. A significant and consistent difference in the population structure and function was found for the bacterial communities from soil irrigated with effluent in comparison to fields irrigated with well water. The diversity index parameters indicated that the microbial community in pulp and paper mill effluent irrigated fields were more diverse in both structure and function. This suggests that the pulp and paper mill effluent is not having a negative effect on the soil microbial community, but in fact may have a positive influence. In terms of soil health, this finding supports the continued use of pulp and paper mill effluent for irrigation. This is however only one aspect of soil health which was evaluated. Further studies on soil resistance and robustness could be undertaken to holistically evaluate soil health in this situation.

Microbial communities play a critical role in degrading organic contaminants in treatment wetlands; however, an understanding of the different roles played by rhizospheric, gravel-associated and interstitial microbial communities is deficient due to a lack of data directly comparing these microbial communities. Community level physiological profiling (CLPP) was used to compare the catabolic capabilities of rhizospheric, gravel-associated and interstitial microbial communities in vertical-flow planted and unplanted wetland mesocosms. Wetland mesocosms were decommissioned to gather microbial community samples associated with the roots and gravel bed media taken from the top (10 cm depth), middle (30 cm depth) and bottom (60 cm depth). The catabolic capabilities of the rhizospheric microbial communities were seen to be much greater than those of the gravel-associated communities. A decrease in catabolic capability was seen with increasing depth, suggesting that communities near the surface play a larger role in the degradation of carbon-based compounds. A general difference in catabolic profiles based on plant presence/absence was observed for the interstitial water and all gravel-associated samples at all depths, suggesting that the presence of roots within part of the mesocosm not only has a localized effect on the attached microbial population, but also on gravel-associated microbial communities throughout the mesocosms.

Nanoscale zerovalent iron (nZVI) is an emerging technology for the remediation of contaminated sites. However, there are concerns related to the impact of nZVI on in situ microbial communities. In this study, the microbial community composition at a contaminated site was monitored over two years following the injection of nZVI stabilized with carboxymethyl cellulose (nZVI-CMC). Enhanced dechlorination of chlorinated ethenes to nontoxic ethene was observed long after the expected nZVI oxidation. The abundance of Dehalococcoides (Dhc) and vinyl chloride reductase (vcrA) genes, monitored using qPCR, increased by over an order of magnitude in nZVI-CMC-impacted wells. The entire microbial community was tracked using 16S rRNA gene amplicon pyrosequencing. Following nZVI-CMC injection, a clear shift in microbial community was observed, with most notable increases in the dechlorinating genera Dehalococcoides and Dehalogenimonas. This study suggests that coupled abiotic degradation (i.e., from reaction with nZVI) and biotic degradation fueled by CMC led to the long-term degradation of chlorinated ethenes at this field site. Furthermore, nZVI-CMC addition stimulated dehalogenator growth (e.g., Dehalococcoides) and biotic degradation of chlorinated ethenes.

The study of bacterial communities in microbially-mediated water treatment systems is becoming increasingly popular. Aquatic bacterial communities are often found in fixed-film environments, residing within a matrix of extracellular polymeric substances commonly referred to as a biofilm. A method for detaching the biofilm is required to either enumerate or characterize these bacterial communities. There are a variety of detachment methods including scraping, swabbing, shaking, sonication, blending, and digestion. The objective of this work was to develop an agitation-based protocol for detachment of culturable bacterial communities from the biofilm surrounding pea gravel from constructed wetland mesocosms. Three different protocol factors were systematically investigated using a triplicated 2(3) factorial design to determine the most effective detachment protocol. Factors studied included: the use of either tap water or phosphate buffer as the shaking/detachment solution; the use of either manual-shaking at room temperature or mechanical shaking at 30 degrees C; and the presence or absence of an enzyme cocktail consisting of lipase, beta-galactosidase and alpha-glucosidase. The resulting suspensions were evaluated for organics, inorganics, culturable bacteria, community level physiological profile (CLPP) and several BIOLOG ECO plate substrate related diversity indices. Using these metrics, the most effective shaking/detachment protocol was identified as mechanical shaking for 3h at 30 degrees C using a phosphate buffer with an enzyme cocktail.

Microbial communities certainly have an influence on the treatment performance of constructed wetlands (CWs); however, microbial community structure or microbial activity (MA) is rarely concurrently or comparatively quantified in relation to treatment performance. The objective of this study was to better understand the influence of the resident CW microbial community on water treatment performance in CWs. Using laboratory-scale mesocosm wetlands, several CW design variables and water chemistry variables were quantitatively and comparatively determined to assess their role in Fe(II) removal from simulated acid mine drainage (AMD). Initial AMD pH, initial AMD Fe(II) concentration, and overall wetland MA had a significant effect on an apparent first-order iron removal rate constant. Under the aerobic conditions used in this study, the presence of Phragmites australis did not have a significant effect on treatment performance. Of all the factors studied, the MA associated with the fixed microbial co...

The field of treatment wetlands (TWs) is rapidly expanding and, arguably, is tasked with studying and understanding one of the most complex water treatment systems available. Microbial communities are generally considered to be responsible for the majority of wastewater constituent degradation in TWs. However, they are also known to be spatially heterogeneous, temporally dynamic, as well as structurally and functionally diverse. Presented here is a meta-analysis of all peer reviewed TW journal articles which utilized a microbial community assessment methodology over the period of 1988 to July 2016. A total of 1101 papers were reviewed, 512 from 1988 to 2012, 215 of which included a microbial community assessment aspect and were subsequently classified as representing past research, and 589 from 2013 to July 2016, 196 of which were classified as representing current TW microbial community research. In general, TW microbial community research has increased over time, with a marked surge in the past four years. Microbial community structure is currently the most commonly used methodological type followed by activity, enumeration and function, respectively. Areas of research focus included nitrogen transformations (156), organic degradation (33), and emerging contaminants (32), with general characterization studies also accounting for a significant proportion (243). Microbial communities from a range of TW systems have been investigated over the last four years with meso-scale (10–1000 L) being the most commonly studied system size followed by large-scale (>100,000 L), micro-scale (

Community-level physiological profiling (CLPP) is a technique which offers an easily applied protocol yielding information regarding mixed microbial community function and functional adaptations over space and time. Different communities can be compared and classified based on sole carbon source utilization patterns (CSUPs) gathered using BIOLOG microplates. One of the most challenging aspects associated with the CLPP method is in the data analysis. This chapter describes the relatively simple CLPP laboratory protocol and provides a detailed description of different data analysis techniques.

Changes in the bacterial community in the interstitial water of 5 different constructed wetland mesocosms were studied over a 22-day period following exposure to simulated acid mine drainage (AMD). The community-level physiological profile (CLPP) of each mesocosm was assessed using substrate utilization patterns gathered via BIOLOG™ ECO plates. Principal component analysis (PCA) of the BIOLOG™ ECO plate data proved feasible and useful in characterizing the interstitial bacterial community in the constructed wetland mesocosms based on mesocosm characteristics such as fixed biological regime development and plant presence, and was also used to successfully track changes in the interstitial bacterial community in response to AMD exposure. Clustering analysis of the BIOLOG™ ECO plate data was used to characterize the interstitial bacterial community and to validate the mesocosm groupings observed through PCA ordination. The calculation of substrate-based diversity indices from the BIOLOG™ ECO plate data was used to assess the robustness and the degree of change shown by the metabolic fingerprint of the interstitial bacterial community within the mesocosms. The interstitial bacterial community in the constructed mesocosms was shown to be significantly affected after exposure to AMD. Exposure to AMD caused similar bacterial species to detach from the fixed biotic regime of the mesocosms. It was also shown that mesocosms planted with Phragmites australis did not experience as great an ecological shift in the microbial ecology of the interstitial water after exposure to AMD as did the unplanted mesocosms. The substrate-based diversity indices for the planted mesocosms were also found to be more stable, after exposure to AMD, than those for the unplanted mesocosms. It is possible that the interaction between the plant root system and the substrate biological regime, collectively called the rhizosphere, may create a more ecologically robust and stable treatment system.