Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “microbial community composition”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 541 records · Page 30Linked to original sources

An assessment of natural biotransformation of petroleum hydrocarbons and chlorinated solvents at an aquifer plume transect.

Field biogeochemical characterization and laboratory microcosm studies were performed to assess the potential for future biotransformation of trichloroethylene (TCE) and toluene in a plume containing petroleum hydrocarbons and chlorinated solvents at the former Wurtsmith Air Force Base in Oscoda, MI. In situ terminal electron accepting processes (TEAPs), contaminant composition and microbial phylogeny were studied at a plume transect 100 m downgradient of the source. The presence of reduced electron acceptors, relevant microbial communities, and elevated dissolved methane and carbon dioxide concentrations at the transect, as well as downgradient accumulation of BTEX metabolites and dechlorination products, indicated that past or current reductive dechlorination at the transect was likely driven by BTEX biodegradation in the methanogenic zone. However, TCE and toluene mineralization in sediment-groundwater microcosms without added electron acceptors did not exceed 5% during 300 days of incubation and was nearly invariant with original sediment TEAP, even following amendments of nitrogen and phosphorus. Mineralization rates were on the order of 0.0015-0.03 mumol/g day. After 8 months, microcosms showed evidence of methanogenesis, but CH4 and CO2 production arose from the degradation of contaminants other than toluene. Cis-dichloroethylene was observed in only one methanogenic microcosm after more than 500 days. It appears likely that spatially and temporally dynamic redox zonation at the plume transect will prevent future sustained reductive dehalogenation of highly chlorinated solvents, for during the course of a year, the predominant TEAP at the highly contaminated water table shifted from methanogenesis to iron- and sulfate-reduction. It is recommended that biotransformation studies combine considerations of long-term, spatially relevant changes in redox zonation with laboratory-scale studies of electron donor utilization and cometabolic substrate transformation to yield a more accurate assessment of natural bioattenuation of specific pollutants in aquifers contaminated by undefined organic waste mixtures.

Biotransformation↗

A microbial world within us.

The microbial world within us includes a vast array of gastrointestinal (GI) tract communities that play an important role in health and disease. Significant progress has been made in recent years in describing the intestinal microbial composition based on the application of 16S ribosomal RNA (rRNA)-based approaches. These were not only instrumental in providing a phylogenetic framework of the more than 1000 different intestinal species but also illustrated the temporal and spatial diversity of the microbial GI tract composition that is host-specific and affected by the genotype. However, our knowledge of the molecular and cellular bases of host-microbe interactions in the GI tract is still very limited. Here an overview is presented of the most recent developments and applications of novel culture-independent approaches that promise to unravel the mechanisms of GI tract functionality and subsequent possibilities to exploit specifically these mechanisms in order to improve gut health.

Animals↗

Eubacterial 16S-rDNA amplicon profiling: a rapid technique for comparison and differentiation of heterotrophic plate count communities from drinking water.

Determination of the heterotrophic plate count (HPC) is commonly used as a surrogate to assess the general microbial water quality in drinking water. For routine monitoring applications, the HPC is investigated in a quantitative way. However, qualitative data about the HPC bacterial community composition and/or population dynamics are required for particular situations. In order to provide fast and efficient qualitative approaches, molecular biological DNA profiling techniques seem to be suitable tools for the analysis of the total HPC community composition. In this work a DNA profiling technique is presented, which was recently demonstrated by our group to have potential for the rapid qualitative comparison and differentiation of HPC communities from raw and drinking water. The presented approach consists of a polymerase chain reaction (PCR)-based denaturing gradient gel electrophoresis (DGGE) for the generation of 16S-rDNA amplicon fingerprints from whole HPC community DNA extracts. In the context of this proceeding, the methodical background is presented and possible scientific merits as well as potential water management applications are discussed. Selected examples of (i) the demonstration of selective growth of HPC populations on different media and the comparison to the total in situ drinking water eubacterial community, (ii) the screening for HPC community variations at different locations of a drinking water distribution system, and (iii) the influence assessment on groundwater HPC communities by an infiltrating treated sewage effluent (bacterial source tracking) are given.

Colony Count, Microbial↗

From papyrus to compact disc: the microbial deterioration of documentary heritage.

Highly significant evidence of the intellectual and cultural efforts of the human race is contained in documents. They take many forms, from papyri through paper to modern magnetic media and optical records. These items are mainly made of organic materials many of which contain polymers, which span from cellulose and its derivatives to synthetic resins. As with other manmade objects, however, documentary heritage is susceptible to chemical, physical, and biological damage. For the colonization and establishment of any biological community, the composition of materials used, their status of conservation, and environmental and climatic factors, such as temperature and humidity, are important elements to take into account. This article covers the scientific investigation of microbial degradation of documents, which is one of the most serious and underappreciated sources of damage to library and archival materials. In particular, although less known, modern records, including compact discs, are also subjected to biodeterioration. Archival and library material preservation broadly encompasses those activities and functions designed to produce a suitable and safe environment that extends the life of collections in useable condition for as long as is feasible. In the literature quoted, key information is also provided to avoid or limit microbial growth and some conservation treatments are also reported.

Animals↗

Characterization of Microbial Consortia in Paddy Rice Soil by Phospholipid Analysis.

Microbial biomass and community structure in paddy rice soil during the vegetation period of rice were estimated by analysis of their phospholipid fatty acids (PLFA), hydroxy fatty acids of lipopolysaccharides (LPS-HYFA), and phospholipid ether lipids (PLEL) directly extracted from the soil. A clear change in the composition of the community structure at different sampling periods was observed, indicated by the principal component analysis of the PLFA. A dramatic decline of ester-linked PLFA was observed in the soil samples taken at the second sampling time. In contrast to the ester-linked PLFA, the non-ester-linked PLFA composition did not change. The hydroxy fatty acids of lipopolysaccharides as well as ether lipids decreased consecutively during the observation period. Total microbial abundance was estimated to be (4.1-7.3) x 10(9) cells g(-1) soil (dry weight). About 44% account for aerobic and 32% for facultative anaerobic bacteria, and 24% for archaea, on average. According to the profile and patterns of PLFA in the soil sample, it may be suggested that the paddy soil at the August sampling period contained more abundant facultative anaerobic bacteria (ca. 36%) and archaea (ca. 37%), but the total microbial biomass was significantly lower than in the remaining sampling periods. As the plant approached maturity, the microbial community structure in the soil changed to contain more abundant Gram-negative bacteria and methanotrophs.

Journal Article↗

[Experimental study of Microcystis-associated and free-living cyanobacteria].

In the experiment with water from the hypereutrophic Lake Frederiksborg Slotso (Denmark) sampled during the autumn peak of Microcystis growth, the quantity and production of free-living and cyanobacteria-associated heterotrophic bacteria were determined, as well as the extracellular enzymatic (aminopeptidase) activity. The functional diversities of associated and free-living bacterial communities were additionally compared using BIOLOG GN microplates to reveal the possible export of Microcystis-attached bacteria into ambient water. It has been shown that the cell size, production values, and growth rates of associated bacteria were less than those of free-living bacteria. At the same time, the potential aminopeptidase activity of associated bacteria was always higher than that of free-living bacteria. The experimental results have shown significant compositional differences in the structure of bacterial communities from different habitats.

Aminopeptidases↗

Determining rates of change and evaluating group-level resiliency differences in hyporheic microbial communities in response to fluvial heavy-metal deposition.

Prior field studies by our group have demonstrated a relationship between fluvial deposition of heavy metals and hyporheic-zone microbial community structure. Here, we determined the rates of change in hyporheic microbial communities in response to heavy-metal contamination and assessed group-level differences in resiliency in response to heavy metals. A controlled laboratory study was performed using 20 flowthrough river mesocosms and a repeated-measurement factorial design. A single hyporheic microbial community was exposed to five different levels of an environmentally relevant metal treatment (0, 4, 8, 16, and 30% sterilized contaminated sediments). Community-level responses were monitored at 1, 2, 4, 8, and 12 weeks via denaturing gradient gel electrophoresis and quantitative PCR using group-specific primer sets for indigenous populations most closely related to the alpha-, beta-, and gamma-proteobacteria. There was a consistent, strong curvilinear relationship between community composition and heavy-metal contamination (R(2) = 0.83; P < 0.001), which was evident after only 7 days of metal exposure (i.e., short-term response). The abundance of each phylogenetic group was negatively affected by the heavy-metal treatments; however, each group recovered from the metal treatments to a different extent and at a unique rate during the course of the experiment. The structure of hyporheic microbial communities responded rapidly and at contamination levels an order of magnitude lower than those shown to elicit a response in aquatic macroinvertebrate assemblages. These studies indicate that hyporheic microbial communities are a sensitive and useful indicator of heavy-metal contamination in streams.

DNA, Bacterial↗

Host-virus dynamics in anaerobic digesters facing abiotic inhibition.

Viruses play a major role in controlling the structure and dynamics of microbial communities in anaerobic digesters, ecosystems sensitive to disturbances that inhibit methane production. Here, we studied the interplay between abiotic disturbances, microbiome and virome composition, and process performance, to assess whether provirus induction can be triggered by abiotic stresses known to inhibit anaerobic digestion (ammonium, phenol and sodium chloride). We monitored viral dynamics in batch mesophilic anaerobic digesters fed with biowaste through shotgun metavirome sequencing. The diversity of both prokaryotes and viruses was high, with Clostridiales dominating the prokaryotic community and Caudoviricetes dominating the viromes. We identified 132 viral contigs and 19 host genera that were differentially abundant under disturbed conditions. No significant impact of the tested abiotic stresses on provirus induction was observed under the current experimental and analytical framework. The results were consistent with viruses exerting steady, background-level predation through a putative combination of kill-the-winner dynamics at the sub-genus level and piggyback-the-winner dynamics, rather than stress-triggered, synchronous lytic bursts. A few auxiliary metabolic genes were detected, potentially targeting carbon, sulfur and cofactor metabolism in anaerobic digestion. Temperate viruses were dominant, representing up to 71% of the viral genomes confirmed as complete across all conditions. Electron microscopy analysis revealed diverse virus-like particles, including head-tailed particles typical of Caudoviricetes, but also spherical, rod-shaped and spindle-shaped particles typical of archaeal viruses. Notably, we present a new virus family, Eurekaviridae, of spindle-shaped viruses associated with methanogenic archaea.

Anaerobiosis↗

Unveiling microbial risks in Chinese household dust: a comprehensive analysis from absolute abundance to virulence unit.

BACKGROUND: People spend the majority of their lives indoors, yet the risk and virulence potential of household microbiota remain largely unexplored, particularly in developing countries. RESULTS: Here, we conducted a nationwide survey on both dust samples and health information across 118 Chinese households. The microbiota composition and its functional units were analyzed using absolute 16S rRNA/ITS sequencing, metagenomics, and metaproteomics. Cross-domain network analysis of the core microbial communities revealed robust co-occurrence patterns in household dust. The mean absolute abundance of potentially pathogenic bacteria and fungi in households was 2.39&#x2009;&#xd7;&#x2009;105 and 2.83&#x2009;&#xd7;&#x2009;106 DNA copies/g dust. The potentially pathogenic community was primarily influenced by latitude, relative humidity, and average temperature. Although total absolute abundance was substantially lower in urban areas, the relative abundance of potentially pathogenic bacteria was markedly higher compared to rural environments. While urban-rural differences existed, the underlying statistical drivers were the environmental variables. The absolute abundance of potential pathogens was significantly associated with the prevalence of rhinitis, wheeze, and dermatitis in 266 participants. Children were identified as the highest-risk group from inhalation exposure of average daily dose. A total of 170 bacterial, 223 fungal virulence factors (VFs), and 370 antibiotic resistance genes (ARGs) were detected in dust and dust extracellular vesicle (EV)-associated DNA. EV-associated cargoes contributed 47.13% to the bacterial VF profiles, 11.90% to fungal VF&#xa0;profiles, and 44.45% to ARG profiles. Metaproteomic analysis confirmed the presence of VF profiles in dust EVs, which was further verified by curated proteomics data from 35 household pathogens. CONCLUSIONS: This study provides a comprehensive, quantitative framework linking indoor microbial exposure to health risks, highlighting EVs as a non-negligible, novel, extracellular mechanistic pathway for health impact in household environments. Video Abstract.

Child↗

Definitions of infectious and infectious-like conditions in the lower genital tract of the female.

A large number of factors regulate the composition and dynamics of the microbial ecosystems in the lower female genito-urinary tract. Metabolic activities of certain species of e.g. the vaginal microbial community might give rise to symptomatic infectious-like conditions without activation of the host's defense mechanisms. On the other hand, "true" infections might pass without any obvious symptoms. Similar to other mucosal surfaces, the microbial ecosystems on the periurethral, introital, vaginal and urethral mucosa is dominated by anaerobic bacteria. Some of the infectious-like conditions in the lower female genito-urinary tract involve predominantly anaerobic bacteria of the endogenous flora. A "dynamic" thinking including considerations of microbial and host/parasite interactions is currently replacing the concept of "one microorganism-one disease". The traditionally used clinical terminology has not kept pace with the modern ecological views. We have emphasize the need for unequivocal and strictly defined criteria for the clinical definitions of infectious and infectious-like conditions in the lower female genito-urinary tract.

Adolescent↗

Microbial Transport, Survival, and Succession in a Sequence of Buried Sediments.

Abstract Two chronosequences of unsaturated, buried loess sediments, ranging in age from <10,000 years to >1 million years, were investigated to reconstruct patterns of microbial ecological succession that have occurred since sediment burial. The relative importance of microbial transport and survival to succession was inferred from sediment ages, porewater ages, patterns of abundance (measured by direct counts, counts of culturable cells, and total phospholipid fatty acids), activities (measured by radiotracer and enzyme assays), and community composition (measured by phospholipid fatty acid patterns and Biolog substrate usage). Core samples were collected at two sites 40 km apart in the Palouse region of eastern Washington State, near the towns of Washtucna and Winona. The Washtucna site was flooded multiple times during the Pleistocene by glacial outburst floods; the Winona site elevation is above flood stage. Sediments at the Washtucna site were collected from near surface to 14.9 m depth, where the sediment age was approximately 250 ka and the porewater age was 3700 years; sample intervals at the Winona site ranged from near surface to 38 m (sediment age: approximately 1 Ma; porewater age: 1200 years). Microbial abundance and activities declined with depth at both sites; however, even the deepest, oldest sediments showed evidence of viable microorganisms. Same-age sediments had equal quantities of microorganisms, but different community types. Differences in community makeup between the two sites can be attributed to differences in groundwater recharge and paleoflooding. Estimates of the microbial community age can be constrained by porewater and sediment ages. In the shallower sediments (<9 m at Washtucna, <12 m at Winona), the microbial communities are likely similar in age to the groundwater; thus, microbial succession has been influenced by recent transport of microorganisms from the surface. In the deeper sediments, the populations may be considerably older than the porewater ages, since microbial transport is severely restricted in unsaturated sediments. This is particularly true at the Winona site, which was never flooded.

Journal Article↗

Environmental coupling between metal resistance genes and bacterial communities in Beijing urban green-space soils.

Urban green spaces are intensively managed ecosystems exposed to chronic, multisource, low-intensity anthropogenic inputs. These inputs may alter soil microbial communities and influence the distribution of metal resistance genes (MRGs). However, MRG distributions and their relationships with environmental conditions and bacterial communities remain unclear under the complex, non-extreme pollution conditions typical of these ecosystems. We investigated Beijing urban green spaces as a representative system using metagenomic sequencing and metagenome-assembled genome (MAG) analysis. We characterized soil MRG composition, its environmental associations, and the distribution of potential hosts. MRG composition differed significantly among ecological conservation (EC), transitional urban (TU), and central urban (CU) zones. These differences were closely associated with soil physicochemical properties and bacterial community structure. Available phosphorus (AP) was significantly associated with variation in both bacterial community structure and MRG composition. MAG-based analysis identified distinct potential-host compositions across the three functional zones. Proteobacteria were more frequently represented among dereplicated MAGs from EC soils, whereas Actinobacteria were more frequent in TU and CU soils. Heavy metal concentrations correlated with MRG composition. However, variation partitioning analysis did not identify an independent contribution from heavy metals after accounting for soil physicochemical properties and bacterial community structure. These findings indicate that urban green-space soil monitoring should incorporate environmental conditions and microbial community characteristics rather than rely solely on total metal concentrations.

Soil Microbiology↗

Metagenomic analysis reveals global landscape of viruses in biogeochemical cycles and microbial resistance in paddy soils and wetlands.

Paddy soils and wetlands form a critical soil-water interface that supports global crop production and biogeochemical cycling. Understanding the role of viruses in these ecosystems is vital for predicting ecosystem resilience. Considering the significance of viruses in microbial community structure and environmental pollution, we analyzed 163 metagenomes from 18 countries in Asia, Europe, America, and Australia. We characterized the global distribution and potential ecological functions of viruses through viral auxiliary metabolic genes (vAMGs), antibiotic resistance genes (vARGs), and metal(loid) resistance genes (vMRGs). We found viruses with globally consistent compositions and host profiles, characterized by high richness and a dominance of lysogenic families. We identified 497 vAMGs associated with carbon, phosphorus, nitrogen, and sulfur cycling, and detected 279 vARGs (conferring resistance to 10 antibiotic) and 141 vMRGs (against 7 metal(loids)). These genes exhibited strong co-localization and co-selection patterns, and their transduction can promote the emergence of multi-resistant microbes, reshaping microbial communities. Therefore, viruses are key mobile vectors for the environmental spread of these genes. By quantifying these pathways, we provide a crucial advancement for ecological risk identification and assessment. This meta-analysis provides a comprehensive overview of virus-mediated biogeochemical processes and resistance gene propagation. We demonstrate that viruses can disseminate antibiotic and metal(loid) resistance, a pollution-driven process that poses potential health risks. Furthermore, by regulating key metabolic pathways, viruses can influence greenhouse gas fluxes. Our findings underscore the necessity of integrating viruses into climate models, pollution mitigation strategies, and One Health policies to assess ecological risks and to protect ecosystem and public health.

Wetlands↗

Microbial diversity in water and sediment of Lake Chaka, an athalassohaline lake in northwestern China.

We employed culture-dependent and -independent techniques to study microbial diversity in Lake Chaka, a unique hypersaline lake (32.5% salinity) in northwest China. It is situated at 3,214 m above sea level in a dry climate. The average water depth is 2 to 3 cm. Halophilic isolates were obtained from the lake water, and halotolerant isolates were obtained from the shallow sediment. The isolates exhibited resistance to UV and gamma radiation. Microbial abundance in the sediments ranged from 10(8) cells/g at the water-sediment interface to 10(7) cells/g at a sediment depth of 42 cm. A major change in the bacterial community composition was observed across the interface. In the lake water, clone sequences affiliated with the Bacteroidetes were the most abundant, whereas in the sediments, sequences related to low G+C gram-positive bacteria were predominant. A similar change was also present in the archaeal community. While all archaeal clone sequences in the lake water belonged to the Halobacteriales, the majority of the sequences in the sediments were related to those previously obtained from methanogenic soils and sediments. The observed changes in the microbial community structure across the water-sediment interface were correlated with a decrease in salinity from the lake water (32.5%) to the sediments (approximately 4%). Across the interface, the redox state also changed from oxic to anoxic and may also have contributed to the observed shift in the microbial community.

Bacteroides↗

Molecular analysis of microbial communities in mobile deltaic muds of Southeastern Papua New Guinea.

A culture-independent examination of microbial diversity in mobile deltaic sediments from the Gulf of Papua, Papua New Guinea, was conducted by sequence analysis of 16S rDNA clone library. Universal small subunit primers were used to amplify DNA extracted from the sediment. Of 91 clones randomly selected from the library, 33 contained unique non-chimeric sequences. Analysis of these unique sequences showed that the majority of them belonged to bacteria (94.5%), with proteobacteria being the dominant division (74.8%). One sequence belonging to Crenarchaeota and another to Euryarchaeota were found as well. Bacterial sequences belonging to the following major divisions were identified: Cytophaga-Flexibacter-Bacteroides (5.5%), low GC Gram-positives (1.1%), Nitrospira group (3.3%), OP8 candidate division (2.2%), OS-K candidate division (2.2%), Planctomyces (1.1%), alpha, delta, gamma and epsilon-subdivisions of Proteobacteria (4.4, 20.9, 19.8 and 23.1%, respectively) and Spirochaetales (4.4%). The composition of 16S rDNA library of the Gulf of Papua sediments is similar to those for deepwater sediments from around the Japanese Islands, indicating a possible cosmopolitan nature of microbial communities in suboxic and anoxic sediments of the Pacific. It appears that many Papua/New Guinea sequences are loosely affiliated with bacteria involved in sulfur cycling, thus supporting the hypothesis that the sulfur cycle may be important in early diagenesis of suboxic sediments.

Journal Article↗

A Mini-review of Microbial Consortia: Their Roles in Aquatic Production and Biogeochemical Cycling

Molecular oxygen (O2) is a potent inhibitor of key microbial processes, including photosynthesis, N2 fixation, denitrification, sulfate reduction, methanogenesis, iron, and metal reduction reactions. Prokaryote survival and proliferation in aquatic environments is often controlled by the ability to tolerate exposure to oxic conditions. Many prokaryotes do not have subcellular organelles for isolating O2-producing from O2-consuming processes and have developed consortial associations with other prokaryotes and eukaryotes that alleviate metabolic constraints of high O2. Nutrient transformations often rely on appropriate cellular and microenvironmental, or microzonal, redox conditions. The spatial and temporal requirements for microenvironmental overlap among microbial groups involved in nutrient transformations necessitates close proximity and diffusional exchange with other biogeochemically distinct, yet complementary, microbial groups. Microbial consortia exist at different levels of community and metabolic complexity, as shown for detrital, microbial mat, biofilm, and planktonic microalgal-bacterial assemblages. To assess the macroscale impacts of consortial interactions, studies should focus on the range of relevant temporal (minutes to hours) and spatial (microns to centimeters) scales controlling microbial production, nutrient exchange, and cycling. In this review, we discuss the utility and application of techniques suitable for determining microscale consortial activity, production, community composition, and interactions in the context of larger scale aquatic ecosystem structure and function.

Journal Article↗

Seawater type shapes larval development, intestinal microbiota, and water quality in Macrobrachium rosenbergii.

Giant freshwater prawn (Macrobrachium rosenbergii) has high economic value and extensive aquaculture prospects, and larval quality critically restricts the sustainable development of the industry. To investigate the effects of different seawater sources on larval survival and growth, artificial seawater, natural seawater from Beibu Gulf (China) and East China Sea (China) were used as culture media to compare their influences on larval development and intestinal microbiota of M. rosenbergii. Significant intergroup differences were observed in cultivation outcomes. The larval emergence rate reached the maximum value of 52.1% in Group G (Beibu Gulf natural seawater), followed by 43.57% in Group R (artificial seawater), and only 36.4% in Group Z (East China Sea natural seawater), indicating distinct larval emergence gaps and a gradual decline in larval development efficiency. Intestinal microbiota analysis indicated that Pseudomonadota, Actinomycetota and Bacillota were the dominant phyla in all three groups. The relative abundance of Bacillota increased significantly in Group G on day 10. LEfSe analysis proved that this group owned the most stable microbial structure and highest community diversity, and pronounced structural fluctuations occurred in Group R, suggesting that intestinal microbial profiles can reflect larval developmental conditions. Correlation analysis showed that gut microbial composition was closely correlated with water environmental parameters, and microbial metabolic pathways were strongly associated with larval growth and development. This study indicates that natural seawater from the Beibu Gulf of China is more suitable for healthy larval cultivation of M. rosenbergii. Structural stability and diversity of intestinal microbiota are key factors affecting larval growth. The results offer theoretical references for optimizing artificial seawater formula and improving larval rearing efficiency.

16S rRNA↗

Community structure in a methanotroph biofilter as revealed by phospholipid fatty acid analysis.

The microbial community structure of two biofilters used for the oxidation of methane and organic trace gases generated in landfills was analysed by phospholipid fatty acid composition. Community structure varied with biofilter depth, reflecting varying conditions of substrate supply as well as of organic carbon content, nutrient status and osmotic stress determined by the different materials used for the individual biofilter layers. Both biofilters were dominated by type II methanotrophs. In the biofilter charged with landfill gas containing significant amounts of trace organics, fatty acid 18:1omega7c constituted 87% of the methanotrophic PLFA, while the recognised signature fatty acids 16:1omega8 and 18:1omega8, which were well represented in the other biofilter, were entirely absent. This indicates the development of a highly specific methanotrophic population, presumably as a result of the adaption to continuous organic trace gas exposure.

Biodegradation, Environmental↗