Archaeal Richness Research Articles

Revealing the response of microbial communities to polyethylene micro(nano)plastics exposure in cold seep sediment

To date, multiple studies have shown that the accumulation of microplastics (MPs)/nanoplastics (NPs) in the environment may lead to various problems. However, the effects of MPs/NPs on microbial communities and biogeochemical processes, particularly methane metabolism in cold seep sediments, have not been well elucidated. In this study, an indoor microcosm experiment for a period of 120 days exposure of MPs/NPs was conducted. The results showed that MPs/NPs addition did not significantly influence bacterial and archaeal richness in comparison with the control (p > 0.05), whereas higher levels of NPs (1 %, w/w) had a significant adverse effect on bacterial diversity (p < 0.05). Moreover, the bacterial community was more sensitive to the addition of MPs/NPs than the archaea, and Epsilonbacteraeota replaced Proteobacteria as the dominant phylum in the MPs/NPs treatments (except 0.2 % NPs). With respect to the co-occurrence relationships, network analysis showed that the presence of NPs, in comparison with MPs, reduced microbial network complexity. Finally, the presence of MPs/NPs decreased the abundance of mcrA, while promoting the abundance of pmoA. This study will help elucidate the responses of microbial communities to MPs/NPs and evaluate their effects on methane metabolism in cold seep ecosystems.

Dissolved oxygen shapes the archaeal communities in the seawater of Changjiang Estuary

Archaea play a significant role in regulating the biogeochemical processes of marine ecosystems. In this study, the high-throughput sequencing was used to explore the archaeal communities in the seawater from the hypoxic and non-hypoxic zones of the Changjiang Estuary. Thaumarchaeota dominated the archaeal communities in the hypoxic zones (bottom water), and Euryarchaeota were mainly distributed in the non-hypoxic zones (surface water). However, the diversity and richness of the archaeal communities showed no obvious difference in the hypoxic and non-hypoxic zones. Moreover, Thaumarchaeota and Nitrosopumilales were positively correlated with salinity, but negatively correlated with dissolved oxygen (DO) and temperature. Temperature, phosphorus, and dissolved oxygen had significant correlations with archaeal richness, while ammonia nitrogen was correlated with archaeal diversity. The networks of archaeal communities possessed a high proportion of positive interspecific interaction and revealed that the Marine Group II species may play distinct roles in both hypoxic and non-hypoxic zones. The current work assessed the influence of dissolved oxygen on the archaeal community patterns and network interaction, thereby illumining the community structure shift of archaea caused by the hypoxia phenomenon in the Changjiang Estuary, which laid a foundation for the future studies on the ecological functions of archaea in estuary ecosystems.

Vertical and temporal variations of soil bacterial and archaeal communities in wheat-soybean rotation agroecosystem.

Soil microbes are an essential component of terrestrial ecosystems and drive many biogeochemical processes throughout the soil profile. Prior field studies mainly focused on the vertical patterns of soil microbial communities, meaning their temporal dynamics have been largely neglected. In the present study, we investigated the vertical and temporal patterns of soil bacterial and archaeal communities in a wheat-soybean rotation agroecosystem at a depth of millions of sequences per sample. Our results revealed different vertical bacterial and archaeal richness patterns: bacterial richness was lowest in the deep soil layer and peaked in the surface or middle soil layer. In contrast, archaeal richness did not differ among soil layers. PERMANOVA analysis indicated that both bacterial and archaeal community compositions were significantly impacted by soil depth but unaffected by sampling time. Notably, the proportion of rare bacteria gradually decreased along with the soil profile. The rare bacterial community composition was the most important indicator for soil nutrient fertility index, as determined by random forest analysis. The soil prokaryotic co-occurrence networks of the surface and middle soil layers are more connected and harbored fewer negative links than that of the deep soil layer. Overall, our results highlighted soil depth as a more important determinant than temporal variation in shaping the soil prokaryotic community and interspecific interactions and revealed a potential role of rare taxa in soil biogeochemical function.

Shifts on archaeal community structure in pure and mixed Eucalyptus grandis and Acacia mangium plantations

Archaeal community has important contributors to nutrient cycling in the forest ecosystems. However, how soil-litter attributes shift their community structure remains poorly understood. To date, the structure of the archaeal community has never been reported either in pure or in mixed eucalypt and acacia plantations, especially in tropical soils. Here, we analyzed the archaeal community and performed correlations with C, N and P attributes in soil-litter layers of pure Eucalyptus grandis without (E) and with N fertilization (E + N), a mixed system of E. grandis and Acacia mangium (E + A), and a pure A. mangium (A) plantation. We extracted DNA from soil (0–20 cm) and litter samples at 27 and 39 months after planting and sequenced the archaeal 16S rRNA gene. We also analyzed the abundance of 16S rRNA and amoA genes by quantitative PCR and assessed the correlations between molecular data with soil-litter attributes (i.e., microbial and enzyme activities, and C, N and P contents). The high-throughput sequencing of the archaeal 16S rRNA gene revealed that the treatments influenced the archaeal community structure. However, the litter layer showed more significant modifications, since archaeal richness, diversity, and the relative abundance of Thaumarchaeota increased in the litter of pure acacia and mixed treatments at both, 27 and 39 months after planting. There was no clear pattern regarding the abundance of functional genes in the soil, but archaeal structure responded to treatments in the litter layer, in which NH4+, total-N and the C/N ratio were the most important attributes for community group differentiation. Our study provides novel insights into the structure and function of archaea in pure and mixed forest systems, but highlights that young mixed plantations exert a low effect on soil community structure. Archaeal community may have an important role in nutrient cycling in the litter interface, especially related to the N cycle in the initial stages of tree development.

新疆天山北坡不同盐湖微生物菌群结构及其影响因子

新疆分布的众多湖泊由于干旱气候成盐作用强烈，近半数已演化到盐湖发展阶段，不同盐湖中也因此蕴含着丰富的耐盐及嗜盐微生物资源。为更好的掌握新疆盐湖微生物资源分布规律及对环境因子变化的响应规律，利用高通量测序技术对新疆天山北坡5个不同演化阶段盐湖湖底沉积物中细菌、古菌多样性和菌群结构及其主要驱动因子进行研究，探讨盐湖演化过程中原核微生物群落结构变化规律。分别采集5个盐湖湖底沉积物样本，进行理化因子测试与细菌和古菌16S rRNA扩增子测序分析，比较不同盐湖理化性质和原核微生物菌群差异，并对原核微生物丰度与环境因子进行关联分析。实验结果表明：5个盐湖湖底沉积物总盐和Na⁺含量顺序为：巴里坤湖 > 伊吾湖 > 艾比湖 > 盐湖 > 柴窝堡湖，除艾比湖外其他四个盐湖沉积物均呈碱性。Alpha多样性结果显示5个盐湖细菌richness、chao1、ACE和shannon丰富度指数均大于古菌相应丰富度指数，不同盐湖细菌丰富度指数差异较大，古菌丰富度指数差异相对较小。从5个盐湖湖底沉积物中共检测获得细菌58门、68纲、138目、253科和560属，古菌4门、8纲、12目、21科和60属，细菌以变形菌门为主，古菌以广古菌门为主。不同盐湖细菌和古菌优势属种类均不相同，巴里坤湖主要是一些嗜盐和耐盐细菌属，而伊吾湖主要是嗜盐和耐盐古菌属，PCoA分析结果也表明不同盐湖微生物在OTUs水平有其独特菌群结构类型。RDA和Bioenv分析结果表明，盐湖湖底沉积物中微生物菌群群落结构主要受Na⁺和总盐（TS）浓度的影响，对细菌菌群结构影响较大，而古菌菌群结构可能受多种理化因子共同调节。此外，盐湖特殊卤水成分会对微生物群落结构产生重大影响。;There are many lakes in Xinjiang, but nearly half of the lakes have evolved to the stage of salt lake development because of the strong salt formation effect in arid climate. The different salt lakes contain rich resources of halophilic and halotolerant microorganisms. In order to better acquire the distribution of microbial resources and the response to environmental factors of salt lakes in Xinjiang, the bacterial and archaeal diversities of five salt lakes bottom sediment at different evolutionary stages of Xinjiang Tianshan north slope. The main driving factors were studied using the high-throughput sequencing technique in this paper to reveal the pattern of microbial community structure change during the salt lake evolution process. The sediment samples from the bottom of five salt lakes were collected, the sediment properties were tested, and the bacterial and archaeal 16S rRNA gene were sequenced. In the five salt lakes, the differences of sediment properties and microbial community structure were compared and the correlation of microbial richness and environmental factors sediment was analyzed. The results showed that the order of total salt and Na⁺ content in the bottom sediments of the five salt lakes was Barkol lake > Yiwu lake > Ebinur lake > Yanhu lake > Chaiwobao lake. The sediments of other four salt lakes are alkaline except Ebinur lake. Alpha diversity displayed that the bacterial richness, chao1, ACE and Shannon richness indexes of the five salt lakes were all higher than the corresponding richness indexes of archaea. The diversity of bacterial richness indexes was greater than that of archaeal richness indexes in these lakes. Through the annotation with sliva database, the bacterial and archaeal communities containing 58 phyla, 68 classes, 138 orders, 253 families, 560 genera and 4 phyla, 8 classes, 12 orders, 21 families, 60 genera, respectively, were found in the bottom sediments of the five salt lakes, in which Proteobacteria was the main phylum of bacteria and Euryarchaeota was the main phylum of archaea. The dominant genus of bacteria and archaea in different salt lakes are different, for example, Barkol lake was mainly some halophilic and halotolerant bacterial genus and Yiwu lake was mainly some halophilic and halotolerant archaeal genus. The PCoA analysis results also demonstrated that the different salt lakes had their unique microbial community structure at the operational taxonomic units (OTUs) level. The results of RDA and Bioenv analysis showed that the microbial community structure in the sediments of the salt lake bottom was mainly affected by the Na⁺ and total salt concentration, while the archaeal community might be regulated by many physical and chemical factors. Moreover, the special brine components of the salt lake would have a significant impact on the microbial community structure.

A pioneer calf foetus microbiome

Foetus sterility until parturition is under debate due to reports of microorganisms in the foetal environment and meconium. Sufficient controls to overcome sample contamination and provide direct evidence of microorganism viability in the pre-rectal gastrointestinal tract (GIT) have been lacking. We conducted molecular and culture-based analyses to investigate the presence of a microbiome in the foetal GIT of calves at 5, 6 and 7 months gestation, while controlling for contamination. The 5 components of the GIT (ruminal fluid, ruminal tissue, caecal fluid, caecal tissue and meconium) and amniotic fluid were found to contain a pioneer microbiome of distinct bacterial and archaeal communities. Bacterial and archaeal richness varied between GIT components. The dominant bacterial phyla in amniotic fluid differed to those in ruminal and caecal fluids and meconium. The lowest bacterial and archaeal abundances were associated with ruminal tissues. Viable bacteria unique to the ruminal fluids, which were not found in the controls from 5, 6 and 7 months gestation, were cultured, subcultured, sequenced and identified. We report that the foetal GIT is not sterile but is spatially colonised before birth by a pioneer microbiome.

Microbial diversity in fracture and pore filling gas hydrate-bearing sediments at Site GMGS2-16 in the Pearl River Mouth Basin, the South China Sea

Gas hydrate systems are unique habitats for microorganisms in deep marine sediments, and gas hydrate reservoirs can be divided into focused high-flux and distributed low-flux gas hydrate systems. Little is known about the microbial distribution patterns in these systems, especially in the South China Sea (SCS). In this study, a macroscopic fracture filling gas hydrate zone (GHZ) and a microscopic pore filling GHZ, used as analogs to focused high-flux gas hydrate systems and distributed low-flux gas hydrate systems, were sampled and microbial diversity was investigated at Site GMGS2-16 in the northern SCS during the GMGS2 gas hydrate expedition based on high-throughput 16S rRNA gene sequencing. Compared to previous studies of the gas hydrate-bearing sites, high microbial diversity was observed in the sulfate methane transition zone (SMTZ) at Site GMGS2-16, and ANME-1b, a clade of anaerobic methanotrophic archaea (ANME), may mainly perform anaerobic oxidation of methane (AOM) in partnership with Desulfarculaceae and Desulfobacteraceae. For the GHZ (fracture-fill GHZ and pore-fill GHZ) and non-GHZ (SMTZ and Other, Other refers to the depth of 31.0-179.5mbsf), the bacterial richness indices (Shannon and inverse Simpson) revealed higher diversity in the GHZ than in the non-GHZ, while the archaeal richness indices showed a contrary pattern. Non-metric multidimensional scaling ordination revealed no significant differences in archaeal communities between the GHZ and non-GHZ, while differences between these zones were discovered in bacterial communities (P < .05), as the relative abundances of Bacilli and Clostridia (Phylum Firmicutes), Bacteroidia (Phylum Bacteroidetes), Alphaproteobacteria, Acidobacteria were significantly higher in the GHZ samples than in the non-GHZ samples. For the fracture-fill GHZ and pore-fill GHZ, the archaeal richness indices showed a higher diversity in the fracture-fill GHZ than in the pore-fill GHZ. High relative abundance of Hadesarchaea were found in the GHZ, especially in the pore-fill GHZ (accounting for 92.0–94.3% of the archaeal sequences), which might indicate Hadesarchaea play a vital role in the biogeochemical processes. For bacteria, the diversity indices were similar between the fracture-fill GHZ and the pore-fill GHZ, and no significant differences in bacterial communities were discovered between the two zones. Our study has provided new information for understanding the microbial diversity of the gas hydrate systems.

Alterations of bacterial and archaeal communities by freshwater input in coastal wetlands of the Yellow River Delta, China

Freshwater input has been widely used for wetland restoration. However, the consequences of freshwater input on bacteria and archaea remain poorly understood. Here, we examined the bacterial and archaeal diversity and community structure through high-throughput sequencing of 16S rRNA genes. Soil samples at a depth of 0–10 cm were collected in various kinds of Phragmites australis wetlands (flooded freshwater-restored (FW), nonflooding (PW) and tidal flooding (TW)) to investigate how the diversity and community structure of bacteria and archaea responded to freshwater input. The alpha-diversity metrics revealed that the bacterial richness and diversity in FW did not significantly differ from those in PW and TW (p > 0.05). However, archaeal richness and diversity was higher in FW than in PW (p < 0.05). Firmicutes and Crenarchaeota constituted the predominant bacterial and archaeal phyla in FW, respectively, whereas Proteobacteria (bacteria) and Thaumarchaeota (archaea) exhibited the highest relative abundance in both PW and TW. The community structure of bacteria and archaea in TW differed from those in FW and PW, as revealed by beta diversity metrics and the analysis of similarities. Moreover, linear discriminant analysis effect size indicated that the largest number of discriminating bacterial and archaeal taxa was found in TW. The Mantel test and Spearman correlation analysis showed that environmental variables (i.e. salinity, soil organic matter and soil texture) influenced the bacterial and archaeal diversity and community structure. And soil salinity parameters played a predominant role in shaping bacterial and archaeal communities. Overall, our findings indicated that freshwater input led to variations in bacterial and archaeal communities.

Bacterial and archaeal compositions and influencing factors in soils under different submergence time in a mercury-sensitive reservoir.

Soils in the water-level-fluctuating zone (WLFZ) of Three Gorges Reservoir (TGR) inundated by water for different periods of time are confirmed to have disparate characteristics to mercury (Hg), and thus it is of great significance to further investigate microbial compositions and influencing factors. The objective of this study was to compare bacterial and archaeal richness, α-diversities and compositions, as well as affecting variables, especially Hg concentrations, among soils under different submergence time-SI (inundated soil), SS (semi-inundated soil), SN(non-inundated soil) and SSe (sediment)-based on high throughput sequencing. Results showed that sediment had significantly higher bacterial and archaeal richness and α-diversities than the other soil types. Anaerolinea and Aeromonas, as well as Altiarchaeales, Nitrosoarchaeum, and Methanosarta were dominant in SSe, while sharply decreasing in the other soil types, with significant difference among groups. An unclassified genus in SCG critically predominating in SI, SS and SN, drastically reduced in SSe, with extremely significant difference among groups. Bathyarchaeota and Nitrososphaera, both dominating in SSe, decreased dramatically and almost vanished in SI and SN. All the variables except pH posed a significant positive effect on bacterial and archaeal compositions in SSe, while opposite effect in the other three soil types. MeHg and THg concentrations had relatively weaker effects on microbial compositions comparing to variables like NH4+, CEC, OM and SO42+.

Methanogenic community during the anaerobic digestion of different substrates and organic loading rates.

Three anaerobic reactors using pig manure (PM), maize straw (MS), and a mixture of the two as substrates were compared for archaeal community structure and diversity, and for methanogens response to increased organic loading rate (OLR, expressed in the mass of volatile solid (VS)). Methanogenic archaeal richness during codigestion of pig manure with maize straw (ACE: 2412) was greater than that during the others (ACE: 1225, 1467) at an OLR of 4 g L−1 day−1, accompanied by high specific methane yield. Euryarchaeota and Crenarchaeota predominated during overall digestion of different substrates; with relative abundances of 63.5%–99.0% and 1.0%–36.3%, respectively. Methanosarcina was the predominant genus that accounted for 33.7%–79.8% of the archaeal community. The diversity in the PM digester decreased with increase in OLR, but increased in the MS digester. The diversity was stable during the codigestion with increased OLR. The relative abundances of hydrogenotrophic methanogens increased by 2.6 and 2.1 folds; the methanogenic community shifted from acetoclastic to hydrogenotrophic methanogens during digestion of MS, and of the mixture of MS and PM. Canonical correspondence analysis revealed a strong relationship between reactor parameters and methanogenic community.

Increasing aridity affects soil archaeal communities by mediating soil niches in semi-arid regions

Soil archaea plays a vital role in the functioning of dryland ecosystems, which are expected to expand and get drier in the future as a result of climate change. However, compared with bacteria and fungi, the impacts of increasing aridity on archaea in these ecosystems remain largely unknown. Here, soil samples were collected along a typical aridity gradient in semi-arid regions in Inner Mongolia, China, to investigate whether and how the increasing aridity affects archaeal communities. The results showed that archaeal richness linearly decreased with increasing aridity. After partialling out the effects of soil properties based on partial least squares regression, the significant aridity-richness relationship vanished. The composition of archaeal communities was distributed according to the aridity gradient. These variations were largely driven by the changes in the relative abundance of Thaumarchaeota, Euryarchaeota and unclassified phyla. Niche-based processes were predominant in structuring the observed archaeal aridity-related pattern. The structural equation models further showed that aridity indirectly reduced archaeal richness through improving soil electrical conductivity (EC) and structured community composition by changing soil total nitrogen (TN). These results suggested that soil salinization and N-losses might be important mechanisms underlying the increasing aridity-induced alterations in archaeal communities, and highlighted the importance of soil niches in mediating the indirect impacts of increasing aridity on archaea.

Evaluation of different air dosing strategies to enhance H2S removal in microaerobic systems treating low-strength wastewaters

ABSTRACT This study aimed to evaluate different air dosing strategies such as microaeration flow rates and air dosing points to enhance H2S removal in microaerobic systems treating low-strength wastewaters. Efficiency and stability of the reactors, as well as biogas quality, were assessed, and microbial community changes were evaluated using the PCR-DGGE technique. The results showed that the air dosing point affected the H2S concentration and that air dosing at the headspace promoted the highest H2S removal efficiency. The airflow rate also affected the process, since H2S concentration in the biogas was higher at 0.1 mL air.min−1 than at 0.3 mL air.min−1. The methane concentration in the biogas was also affected by both air dosing point and flow rate, since the lowest value was observed at the highest airflow rate of the headspace dosing point, due to dilution by the N2 influx applied to the system. The highest productivity and operational efficiency were observed at this air dosing point, with this airflow (HD0.3), which corroborates with the operational results and the ecological parameters, since the microaeration at this stage promoted high bacterial and archaeal species richness and diversity, optimum functional organization, high COD and H2S removal efficiencies.

Spatio-temporal shifts in the archaeal community of a constructed wetland treating river water

The distribution of archaeal community and the associated environmental variables in constructed wetland (CW), especially in free water surface flow CW (FWSF-CW), remain poorly understood. The present study explored the spatial and temporal dynamics of archaeal community in an FWSF-CW used for surface water treatment and evaluated the driving environmental variables. The archaeal density varied considerably among sites and seasons, ranging from 3.37×108 to 3.59×109 16S rRNA gene copies per gram dry sediment/soil. The archaeal population density was adversely affected by high temperatures and tended to be lower during summer than during spring and winter. Moreover, considerable spatio-temporal variations of archaeal richness, diversity and community structure also occurred in the FWSF-CW. Higher nutrient contents correlated with a lower archaeal richness and diversity. Nitrate and carbon/nitrogen ratio were found to play important roles in shaping the overall archaeal community structure. Euryarchaeota and Bathyarchaeota were the dominant archaeal phyla in wetland sediments, while Thaumarchaeota tended to be dominant in wetland soils. In addition, the wetland archaeal community was related to vegetation type.

Vertical distribution of microbial communities in soils contaminated by chromium and perfluoroalkyl substances

Both Bacteria and Archaea are important players in soil biogeochemical cycles. Both chromium (Cr) and perfluoroalkyl substances (PFASs) are widely present in soil environment. However, the depth-related distribution of microbial community in soils contaminated by Cr or/and PFASs remains unknown. Hence, the present study applied quantitative PCR assay and Illumina MiSeq sequencing to investigate the vertical variations of archaeal and bacterial communities in soils (0.5–12.5m depth) contaminated by chrome plating waste and the potential effects of Cr and PFASs.Both bacterial and archaeal communities displayed the remarkable depth-related changes of abundance (2.16×107–5.05×109 and 4.95×105–2.56×108 16S rRNA gene copies per gram dry soil respectively for Bacteria and Archaea), diversity (bacterial and archaeal Shannon diversity indices of 5.06–6.34 and 2.91–4.61, respectively) and structure. However, at each soil depth, bacterial community had higher abundance, richness and diversity than archaeal community. Soil bacterial communities were mainly composed of Proteobacteria, Chloroflexi, Actinobacteria and Firmicutes, and archaeal communities were dominated by Thaumarchaeota and unclassified Archaea. Moreover, microbial abundance and richness increased with increasing perfluorohexane sulfonate (PFHxS) content. Microbial abundance was correlated to total Cr, and archaeal richness was correlated to total Cr and Cr(IV). In addition, total Cr might be a key determinant of soil microbial community structure.

Direct and indirect effects of native range expansion on soil microbial community structure and function

Summary Analogous to the spread of non‐native species, shifts in native species’ ranges resulting from climate and land use change are also creating new combinations of species in many ecosystems. These native range shifts may be facilitated by similar mechanisms that provide advantages for non‐native species and may also have comparable impacts on the ecosystems they invade. Soil biota, in particular bacteria and fungi, are important regulators of plant community composition and below‐ground ecosystem function. Compared to non‐native plant invasions, there have been relatively few studies examining how soil biota influence – or are influenced by – native species range shifts. Here, we examined how a native range‐expanding sagebrush species (Artemisia rothrockii) affects below‐ground abiotic conditions and microbial community structure and function using next‐generation sequencing coupled with other biotic and abiotic soil analyses. We utilized a range‐expansion gradient, together with a shrub removal experiment and structural equation models, to determine the direct and indirect drivers of these interconnected processes. Sagebrush colonization increased bacterial and archaeal richness and diversity and altered community composition across the expansion gradient. Soil organic C and N and soil moisture increased with sagebrush presence; however, results varied across the expansion gradient. We found no relationship between sagebrush and soil pH; however, pH strongly influenced microbial richness and diversity. Microbial (substrate‐induced) respiration was influenced by soil organic N, as well as microbial diversity and functional group relative abundances, highlighting direct and indirect effects of sagebrush on microbial community structure and function. Microbial community composition of soils after 4 years of sagebrush removal was more similar to communities in shrub interspaces than underneath shrubs, suggesting microbial community resilience. Synthesis. Our results suggest that native range expansions can have important impacts on soil biological communities, soil chemistry and hydrology which can further impact below‐ground ecosystem processes such as nutrient cycling and litter decomposition. The combination of high‐throughput sequencing and structural equation modelling used here offers an exciting yet underutilized approach to understanding how both native and non‐native species’ range expansions may affect the structure and function of soil ecosystems.

Technical, Economical, and Microbiological Aspects of the Microaerobic Process on H2S Removal for Low Sulfate Concentration Wastewaters.

We studied the feasibility of the microaerobic process, in comparison with the traditional chemical absorption process (NaOH), on H2S removal in order to improve the biogas quality. The experiment consisted of two systems: R1, biogas from an anaerobic reactor was washed in a NaOH solution, and R2, headspace microaeration with atmospheric air in a former anaerobic reactor. The microaeration used for low sulfate concentration wastewater did not affect the anaerobic digestion, but even increased system stability. Methane production in the R2 was 14% lower compared to R1, due to biogas dilution by the atmospheric air used. The presence of oxygen in the biogas reveals that not all the oxygen was consumed for sulfide oxidation in the liquid phase indicating mass transfer limitations. The reactor was able to rapidly recover its capacity on H2S removal after an operational failure. Bacterial and archaeal richness shifted due to changes in operational parameters, which match with the system functioning. Finally, the microaerobic system seems to be more advantageous for both technical and economical reasons, in which the payback of microaerobic process for H2S removal was 4.7months.

Substrate influences on archaeal and bacterial assemblages in constructed wetland microcosms

Microorganisms in surface water constructed wetland (CW) play crucial roles in pollutant removal. However, little is known about the diversity and structure of microbial community in surface water CW. The influential factors regulating microbial community diversity and structure remain poorly known. In the present study, Illumina high-throughput sequencing was used to characterize bacterial and archaeal communities in three lab-scale vertical-flow CW (VF-CW) systems with different substrate materials (fine gravel, steel slag or natural zeolite). The depth-related change of archaeal and bacterial community richness, diversity and structure occurred in these three VF-CW systems. Microbial diversity in three VF-CW systems showed the similar depth-related change pattern, but microbial richness illustrated the different change pattern. Substrate type had a profound effect on bacterial richness but only a slight effect on bacterial diversity. Archaeal richness and diversity were affected by substrate type and wetland depth. Moreover, archaeal community had much lower richness and diversity than bacterial community. Archaeal and bacterial community structure was regulated by substrate type and wetland depth. Proteobacteria and Acidobacteria were the most abundant bacterial phyla, while Euryarchaeota was the predominant archaeal phylum.

Bacterial and archaeal communities in the deep-sea sediments of inactive hydrothermal vents in the Southwest India Ridge.

Active deep-sea hydrothermal vents harbor abundant thermophilic and hyperthermophilic microorganisms. However, microbial communities in inactive hydrothermal vents have not been well documented. Here, we investigated bacterial and archaeal communities in the two deep-sea sediments (named as TVG4 and TVG11) collected from inactive hydrothermal vents in the Southwest India Ridge using the high-throughput sequencing technology of Illumina MiSeq2500 platform. Based on the V4 region of 16S rRNA gene, sequence analysis showed that bacterial communities in the two samples were dominated by Proteobacteria, followed by Bacteroidetes, Actinobacteria and Firmicutes. Furthermore, archaeal communities in the two samples were dominated by Thaumarchaeota and Euryarchaeota. Comparative analysis showed that (i) TVG4 displayed the higher bacterial richness and lower archaeal richness than TVG11; (ii) the two samples had more divergence in archaeal communities than bacterial communities. Bacteria and archaea that are potentially associated with nitrogen, sulfur metal and methane cycling were detected in the two samples. Overall, we first provided a comparative picture of bacterial and archaeal communities and revealed their potentially ecological roles in the deep-sea environments of inactive hydrothermal vents in the Southwest Indian Ridge, augmenting microbial communities in inactive hydrothermal vents.

Understanding the anaerobic BTEX removal in continuous-flow bioreactors for ex situ bioremediation purposes

This work aimed to understand the anaerobic BTEX removal in continuous-flow bioreactors for ex situ bioremediation purposes, evaluating the effect of some operational parameters on efficiency, stability and microbial community structure. The influence of the hydraulic retention time, effluent recirculation and co-substrate (ethanol) concentration was investigated on a mesophilic UASB bioreactor operated under methanogenic conditions. The changes on the bacterial and archaeal communities were evaluated in terms of diversity, evenness and richness. Good BTEX removal (∼63%) and reactor stability could still be reached at a HRT of 24h. The impact of the effluent recirculation on BTEX removal was not evident at high co-substrate (ethanol) concentrations, but it was significant when low concentrations were applied. The reduction of ethanol concentration had a positive impact on BTEX removal (from 80% to 86%), especially for benzene (from 51% to 62%). The optimal degree of evenness likely contributed to the relatively high stability of the system in terms of BTEX removal. Changes observed in bacterial and archaeal richness did not match with the functioning of the system. However, dynamics and evenness parameters seemed to be of importance in maintaining a stable reactor performance.

Marine bacterial, archaeal and eukaryotic diversity and community structure on the continental shelf of the western Antarctic Peninsula

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 73:107-121 (2014) - DOI: https://doi.org/10.3354/ame01703 Marine bacterial, archaeal and eukaryotic diversity and community structure on the continental shelf of the western Antarctic Peninsula Catherine M. Luria1,2, Hugh W. Ducklow3, Linda A. Amaral-Zettler1,2,4,* 1Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912, USA 2The Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA 3Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964, USA 4Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, Rhode Island 02912, USA *Corresponding author: amaral@mbl.edu ABSTRACT: The classic view of polar ocean foodwebs emphasizes large predators sustained by energy and material flow through short, efficient diatom-krill-predator food chains. Bacterial activity is generally low in cold polar waters compared to that at lower latitudes. This view appears to be changing, with new studies of microbial foodwebs in Arctic and Antarctic oceans. We characterized bacterial, archaeal, and eukaryotic community diversity and composition from 2 depths (near surface and below the euphotic zone) at 4 sites, including the inshore and offshore, and north and south corners of a sampling grid along the western coast of the Antarctic Peninsula (WAP). We detected up to 2-fold higher richness in microbial eukaryotes at surface and deep inshore northern stations as compared to southern stations, but offshore northern and southern stations revealed either no trend or higher richness at depth in the south. In contrast, bacterial and archaeal richness showed no significant differences either inshore or offshore at northern versus southern extents, but did vary with depth. Archaea were virtually absent in summer surface waters, but were present in summer deep and winter surface samples. Overall, winter bacterial and archaeal assemblages most closely resembled summer sub-euphotic zone assemblages, reflecting well-established seasonal patterns of water column turnover and stratification that result in an isolated layer of ‘winter water’ below the euphotic zone. Inter-domain heterotroph-phototroph interactions were evident from network analysis. The WAP is among the most rapidly warming regions on earth. Our results provide a baseline against which future change in microbial communities may be assessed. KEY WORDS: Antarctica · MIRADA-LTERS · Palmer LTER · Pyrosequencing · V6 · V9 · Microbial oceanography Full text in pdf format Supplementary material PreviousNextCite this article as: Luria CM, Ducklow HW, Amaral-Zettler LA (2014) Marine bacterial, archaeal and eukaryotic diversity and community structure on the continental shelf of the western Antarctic Peninsula. Aquat Microb Ecol 73:107-121. https://doi.org/10.3354/ame01703 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 73, No. 2. Online publication date: October 02, 2014 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2014 Inter-Research.