The influence of water quality on wetland-associated microbial communities (original) (raw)
Related papers
Microbial Ecology, 2019
The impact of contrasting water quality treatments on wetland plant-associated microbial communities was investigated in this study using 12 lab-scale wetland mesocosms (subsurface flow design) planted with reed canary grass (Phalaris arundinacea) or water speedwell (Veronica anagallis-aquatica) over a 13-week period. Mesocosms received water collected from two sites along the Grand River (Ontario, Canada) designated as having either high or poor water quality according to Grand River Conservation Authority classifications. All mesocosms were established using sediment collected from the high water quality site and received water from this source pre-treatment. Resulting changes to microbial community structure were assessed using PCR-denaturing gel gradient electrophoresis (DGGE) on microbial 16S rDNA sequences extracted from rhizoplane, rhizosphere, and water samples before and after exposure to water quality treatments. Functional community changes were determined using Biolog™ EcoPlates which assess community-level carbon source utilization profiles. Wetland mesocosm removal of inorganic nutrients (N, P) and fecal coliforms was also determined, and compared among treatments. Treatment-specific effects were assessed using a repeated measures restricted maximum likelihood (REML) analysis. Structural and functional characteristics of rhizoplane microbial communities were significantly influenced by the interaction between plant species and water treatment (P = 0.04, P = 0.01). Plant species-specific effects were observed for rhizosphere structural diversity (P = 0.01) and wetland water community metabolic diversity (P = 0.03). The effect of water treatment alone was significant for structural diversity measurements in wetland water communities (P = 0.03). The effect of plant species, water quality treatment, and the interaction between the two is dependent on the microhabitat type (rhizoplane, rhizosphere, or water). Rhizoplane communities appear to be more sensitive to water quality-specific environmental changes and may be a good candidate for microbial community-based monitoring of wetland ecosystems.
Ecological Engineering, 2014
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.
Fluctuations in wetland hydrology create an interplay between aerobic and anaerobic conditions, controlling vegetation composition and microbial community structure and activity in wetland soils. In this study, we investigated the vegetation composition and microbial community structural and functional changes along a wetland hydrological gradient. Two different vegetation communities were distinguished along the hydrological gradient; Caricetum gracilis at the wet depression and Arrhenatheretum elatioris at the drier upper site. Microbial community structural changes were studied by a combined in situ 13 CO 2 pulse labeling and phospholipid fatty acid (PLFA) based stable isotope probing approach, which identifies the microbial groups actively involved in assimilation of newly photosynthesized, root-derived C in the rhizosphere soils. Gram negative bacterial communities were relatively more abundant in the surface soils of the drier upper site than in the surface soils of the wetter lower site, while the lower site and the deeper soil layers were relatively more inhabited by gram positive bacterial communities. Despite their large abundance, the metabolically active proportion of gram positive bacterial and actinomycetes communities was much smaller at both sites, compared to that of the gram negative bacterial and fungal communities. This suggests much slower assimilation of rootderived C by gram positive and actinomycetes communities than by gram negative bacteria and fungi at both sites. Ground water depth showed a significant effect on the relative abundance of several microbial communities. Relative abundance of gram negative bacteria significantly decreased with increasing ground water depth while the relative abundance of gram positive bacteria and actinomycetes at the surface layer increased with increasing ground water depth.
Assessing Microbial Community Structure Using LH-PCR in Treatment Microcosm Wetlands
2006
Phosphorus removal in treatment wetlands has been extensively studied over the past thirty years. However, little is known about the structure and diversity of microbial communities that are involved in treatment processes and how these relate to the biogeochemical and phosphorus gradients. We conducted a microcosm study and collected basic data on microbial community structure and diversity as influenced by macrophytes and phosphorus loading that are critical in the treatment efficiency of constructed wetlands. Specifically, we fingerprinted wetland soils using Length Heterogeneity PCR (LH-PCR) and examined microbial diversity of some of those soils by cloning and sequencing community libraries. Principal coordinate analysis (PCO) and analysis of similarity (ANOSIM) of the fingerprints suggested that phosphorus loading has a recognizable impact (Global R= 0.6, p = 2.9 %) in altering soil microbial community structure. LH-PCR products cloned and sequenced also showed that different bacterial groups were selected by either high or low phosphorus treatment. No significant effects of the presence of macrophytes on soil microbial communities were detected (Global R = -0.15; p = 80 %), likely due to sampling errors. Further investigation is needed to more carefully examine the linkages between soil microbial communities and phosphorus removal in treatment wetlands that improves water quality.
Journal of Applied Microbiology, 2006
Aims: To correlate microbial community composition and water quality changes within wetland cells containing varying plant densities and composition in a free water surface (FWS) constructed wetland. Methods and Results: Water chemistry was monitored weekly for nitrate, orthophosphate, and suspended solids, at various sites throughout the wetland for 6 months. Treatment ponds with 50% plant cover had about a 96AE3% nitrate removal. The average change between the influent and effluent was 50-60% nitrate removal and 40-50% orthophosphate removal. Community profile of total DNA, generated by using denaturing gradient gel electrophoresis (DGGE), was used to determine the major microbial composition associated with the wetland sediment, rhizosphere, and surface water. Bacterial cloned libraries were constructed, and 300 clones were analysed by amplified ribosomal DNA restriction analysis (ARDRA) and grouped into operational taxonomic units (OTUs). A total of 35, 31, and 36 different OTU were obtained from sediment, rhizosphere, and surface water, respectively. The bacterial members within the dominant group of our clone library belonged to unclassified taxa, while the second predominant group consisted of members of the phylum Proteobacteria. The dominant organisms within the class were in the c, b, and d classes.
Wetlands Ecology and Management, 2009
We studied redoximorphic features, field indicators and bacterial communities of soils in hummocks and hollows of a palustrine forested wetland in Virginia. We hypothesized that presence of hydric soils, soil physicochemistry and soil bacterial community structure would differ between hummocks and hollows. We fingerprinted soils collected from different microtopographic locations using Length Heterogeneity Polymerase Chain Reaction (LH-PCR) to study their bacterial community structures. Two hummocks had silty/sandy loam soils with mean chroma values of [ 4, showing no indication of 'hydric soils' (i.e., wetland soils). Two hollows, however, had clay loam soils with mean chroma values of 2 with gleying and redox concentrations observed, indicative of seasonally inundated wetlands. The soils of hollows also had higher organic matter content and soil moisture compared to the soils of hummocks (P \ 0.05). Multidimensional scaling (MDS) and Analysis of similarity (ANOSIM) of the fingerprints revealed differences in soil microbial community structures between hummocks and hollows (Global R = 0.30, P \ 0.01). The diversity measures of the fingerprints (Shannon's H 0 ) were also different by microtopography with higher diversity in hollows relative to hummocks (P \ 0.05). LH-PCR proves to be a useful tool in examining bacterial community composition of wetland soils in this study. However, cloning and sequencing of specific community LH-PCR profiles of interest is necessary to fully characterize the community down to genus/species level. With species identities we should be able to not only better explain differences observed in the community profiles, but study their relations to hydrologic and/or physicochemical conditions of wetlands.
Environmental and anthropogenic controls over bacterial communities in wetland soils
Proceedings of the National Academy of Sciences, 2008
Soil bacteria regulate wetland biogeochemical processes, yet little is known about controls over their distribution and abundance. Bacteria in North Carolina swamps and bogs differ greatly from Florida Everglades fens, where communities studied were unexpectedly similar along a nutrient enrichment gradient. Bacterial composition and diversity corresponded strongly with soil pH, land use, and restoration status, but less to nutrient concentrations, and not with wetland type or soil carbon. Surprisingly, wetland restoration decreased bacterial diversity, a response opposite to that in terrestrial ecosystems. Community level patterns were underlain by responses of a few taxa, especially the Acidobacteria and Proteobacteria, suggesting promise for bacterial indicators of restoration and trophic status.
Alteration of soil microbial communities and water quality in restored wetlands
Soil Biology and Biochemistry, 2006
Land usage is a strong determinant of soil microbial community composition and activity, which in turn determine organic matter decomposition rates and decomposition products in soils. Microbial communities in permanently flooded wetlands, such as those created by wetland restoration on Sacramento-San Joaquin Delta islands in California, function under restricted aeration conditions that result in increasing anaerobiosis with depth. It was hypothesized that the change from agricultural management to permanently flooded wetland would alter microbial community composition, increase the amount and reactivity of dissolved organic carbon (DOC) compounds in Delta waters; and have a predominant impact on microbial communities as compared with the effects of other environmental factors including soil type and agricultural management. Based on phospholipid fatty acid (PLFA) analysis, active microbial communities of the restored wetlands were changed significantly from those of the agricultural fields, and wetland microbial communities varied widely with soil depth. The relative abundance of monounsaturated fatty acids decreased with increasing soil depth in both wetland and agricultural profiles, whereas branched fatty acids were relatively more abundant at all soil depths in wetlands as compared to agricultural fields. Decomposition conditions were linked to DOC quantity and quality using fatty acid functional groups to conclude that restricted aeration conditions found in the wetlands were strongly related to production of reactive carbon compounds. But current vegetation may have had an equally important role in determining DOC quality in restored wetlands. In a larger scale analysis, that included data from wetland and agricultural sites on Delta islands and data from two previous studies from the Sacramento Valley, an aeration gradient was defined as the predominant determinant of active microbial communities across soil types and land usage. q
Factors influencing microbial community, structure, diversity and function in treatment wetlands
The use of treatment wetlands (TWs) in the treatment of domestic, municipal and industrial wastewater has been well-documented in past years. Although there are a number of different mechanisms at play in the removal of pollutants in these wetlands, it has been shown that one of the most significant means of wastewater polishing is due to the contribution of microbial communities (Cui et al., 2013; Wu et al., 2012). Microorganisms that occur naturally in wetland environments have the ability to degrade organic compounds and metabolize contaminants, effectively contributing to the transformation and removal of key wastewater parameters such as nitrogen, ammonia, biochemical/chemical oxygen demand (BOD/COD), phosphorus and heavy metals (Faulwetter et al., 2009; Saeed & Sun, 2013). As well, the ability of microorganisms to aggregate together and form unique biofilms creates an even more potent method of wastewater treatment, contributing to pollutant removal by the indirect impact on hydrological parameters and interactions with the rhizosphere (Gagnon & Weber, 2014). Although the specific metabolic processes contributing to wastewater treatment are relatively well understood, the characterization and community structure of microorganisms in TWs are not, and there has been little research conducted on the engineering of wetlands aimed at enhancing microbial activity or specific bacterial processes. In recent years, however, techniques for assessing the function, enumeration, diversity and distribution of microorganisms in treatment wetlands have become increasingly sophisticated, leading to the emergence of more and more studies attempting to identify and control the specific factors influencing microorganisms (Gagnon & Weber, 2014). This paper begins with a summary of the main microbial functions and processes leading to contaminant reduction. It then moves on to outline some of the wetland characteristics that have proven to influence these processes as well as the density, activity and/or structural community of microorganisms. In addition, suggestions will be made throughout this paper about the ability to attenuate microbial treatment by making alterations to these variable wetland characteristics.
Microorganisms, 2020
Constructed wetlands (CWs) are complicated ecosystems that include vegetation, sediments, and the associated microbiome mediating numerous processes in wastewater treatment. CWs have various functional zones where contrasting biochemical processes occur. Since these zones are characterized by different particle-size composition, physicochemical conditions, and vegetation, one can expect the presence of distinct microbiomes across different CW zones. Here, we investigated spatial changes in microbiomes along different functional zones of a free-water surface wetland located in Moscow, Russia. The microbiome structure was analyzed using Illumina MiSeq amplicon sequencing. We also determined particle diameter and surface area of sediments, as well as chemical composition of organic pollutants in different CW zones. Specific organic particle aggregates similar to activated sludge flocs were identified in the sediments. The highest accumulation of hydrocarbons was found in the zones with...