Aquatic Microbial Community Structure and Function Across a Gradient of Logging, Fire, and Industrial Watershed Disturbance

Aquatic Microbial Community Structure and Function Across a Gradient of Logging, Fire, and Industrial Watershed Disturbance
Title Aquatic Microbial Community Structure and Function Across a Gradient of Logging, Fire, and Industrial Watershed Disturbance PDF eBook
Author Caroline Emilson
Publisher
Pages
Release 2014
Genre
ISBN

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The role of microbial communities in the recovery of aquatic ecosystems from watershed disturbance has received little attention despite their important role in energy and nutrient cycling. This study investigates the structure and function of microbial communities on a standardized substrate (alder leaves) in small streams across a wide gradient of watershed disturbances. Microbial communities exhibited variation with disturbance regime with lower hydrolase enzyme activities at all disturbed streams compared to undisturbed streams, and the lowest rates of microbial decomposition, fungal biomass, and differences in microbial community composition at the most severely disturbed streams. Forest and wetland cover were identified as important watershed features that provide DOC to fuel microbial activity in aquatic ecosystems. Increasing road density within the watershed was identified as having a negative impact or association on microbial activity that appeared to be linked to inputs of inorganic solutes that were measured through increased levels of specific conductance in stream water samples. This study is one of the first of its kind and it provides some important evidence that leaf litter associated microbial communities can be influenced by factors linked to watershed disturbance and as such may be useful as indicators of watershed disturbance and potentially the state of recovery of aquatic ecosystems.

Microbial Community Structure and Function in Coarse Woody Debris and Boreal Forest Soils After Intensified Biomass Harvests

Microbial Community Structure and Function in Coarse Woody Debris and Boreal Forest Soils After Intensified Biomass Harvests
Title Microbial Community Structure and Function in Coarse Woody Debris and Boreal Forest Soils After Intensified Biomass Harvests PDF eBook
Author Elizabeth Emily Smenderovac
Publisher
Pages 0
Release 2014
Genre
ISBN

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Intensified biomass harvesting could prove to be negative for forest ecological health through the impacts this type of forest management could exert on microbial community structure and function in forest soils and in CWD pools. Microbial community functional characteristics as well as community structure (through T-RFLP and pyrotag sequencing of ssu rRNA) were assayed soils in a boreal jack pine forest exposed to a clearcut intensified harvesting gradient. Microbial communities within CWD of various decay stages were also assessed in order to determine habitat specificity of the decomposer communities within them. Soil microbial communities were altered by harvesting, but intensification did not cause further disturbance. Soils in harvested sites were different from fire sites also assayed, meaning that these disturbance types may have different impacts on microbial community structure and functioning. CWD communities within logs had different characteristics in different sites. Intensification could reduce site specific organisms important in decay initiation.

Anthropogenic Impacts on the Microbial Ecology and Function of Aquatic Environments

Anthropogenic Impacts on the Microbial Ecology and Function of Aquatic Environments
Title Anthropogenic Impacts on the Microbial Ecology and Function of Aquatic Environments PDF eBook
Author Maurizio Labbate
Publisher Frontiers Media SA
Pages 250
Release 2016-09-06
Genre Microbiology
ISBN 2889199398

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Aquatic ecosystems are currently experiencing unprecedented levels of impact from human activities including over-exploitation of resources, habitat destruction, pollution and the influence of climate change. The impacts of these activities on the microbial ecology of aquatic environments are only now beginning to be defined. One of the many implications of environmental degradation and climate change is the geographical expansion of disease- causing microbes such as those from the Vibrio genus. Elevating sea surface temperatures correlate with increasing Vibrio numbers and disease in marine animals (e.g. corals) and humans. Contamination of aquatic environments with heavy metals and other pollutants affects microbial ecology with downstream effects on biogeochemical cycles and nutrient turnover. Also of importance is the pollution of aquatic environments with antibiotics, resistance genes and the mobile genetic elements that house resistance genes from human and animal waste. Such contaminated environments act as a source of resistance genes long after an antibiotic has ceased being used in the community. Environments contaminated with mobile genetic elements that are adapted to human commensals and pathogens function to capture new resistance genes for potential reintroduction back into clinical environments. This research topic encompasses these diverse topics and describes the affect(s) of human activity on the microbial ecology and function in aquatic environments and, describes methods of restoration and for modelling disturbances.

Microbial Role in the Carbon Cycle in Tropical Inland Aquatic Ecosystems

Microbial Role in the Carbon Cycle in Tropical Inland Aquatic Ecosystems
Title Microbial Role in the Carbon Cycle in Tropical Inland Aquatic Ecosystems PDF eBook
Author André Megali Amado
Publisher Frontiers Media SA
Pages 146
Release 2017-03-15
Genre
ISBN 2889451275

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Aquatic microorganisms are tidily related to the carbon cycle in aquatic systems, especially in respect to its accumulation and emission to atmosphere. In one hand, the autotrophs are responsible for the carbon input to the ecosystems and trophic chain. On the other hand, the heterotrophs traditionally play a role in the carbon mineralization and, since microbial loop theory, may play a role to carbon flow through the organisms. However, it is not yet clear how the heterotrophs contribute to carbon retention and emission especially from tropical aquatic ecosystems. Most of the studies evaluating the role of microbes to carbon cycle in inland waters were performed in high latitudes and only a few studies in the tropical area. In the prospective of global changes where the warm tropical lakes and rivers become even warmer, it is important to understand how microorganisms behave and interact with carbon cycle in the Earth region with highest temperature and light availability. This research topic documented microbial responses to natural latitudinal gradients, spatial within and between ecosystems gradients, temporal approaches and temperature and nutrient manipulations in the water and in the sediment.

Spatio-temporal Variation and Dissolved Organic Carbon Processing of Streambed Microbial Community

Spatio-temporal Variation and Dissolved Organic Carbon Processing of Streambed Microbial Community
Title Spatio-temporal Variation and Dissolved Organic Carbon Processing of Streambed Microbial Community PDF eBook
Author Philips Olugbemiga Akinwole
Publisher
Pages 168
Release 2013
Genre Electronic dissertations
ISBN

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Sedimentary microbial communities play a critical ecological role in lotic ecosystems and are responsible for numerous biogeochemical transformations, including dissolved organic matter (DOM) uptake, degradation, and mineralization. The goals of this study were to elucidate the benthic microbes responsible for utilization of humic DOM in streams and to assess overall variability in microbial biomass and community structure over time and across multiple spatial scales in stream networks, as DOM quality and quantity will likely change with stream order. In Chapter 2, multiple spatial patterns of microbial biomass and community structure were examined in stream sediments from two watersheds; the Neversink River watershed (NY; 1st, 3rd and 5th order streams sampled) and the White Clay Creek watershed (PA; 1st through 3rd order streams sampled). Microbial biomass and community structure were estimated by phospholipid phosphate and phospholipid fatty acids (PLFA) analyses. Multivariate analysis showed that sedimentary C:N ratios, percent carbon, sediment surface area and percent water content explained 68% of the variations in total microbial biomass. Overall, the magnitude of within stream variation in microbial biomass was small compared to the variability noted among streams and between watersheds. Principal component analysis (PCA) of PLFA profiles showed that microbial community structure displayed a distinct watershed-level biogeography, as well as variation along a stream order gradient. Chapter 3 demonstrated that benthic microbial biomass was seasonally dynamic and significantly correlated to a combination of high and low flood pulse counts, variability in daily flow and DOC concentration in the White Clay Creek. Additionally, the seasonal pattern of variation observed in microbial community structure was as a result of shift between the ratios of prokaryotic to eukaryotic component of the community. This shift was significantly correlated with seasonal changes in median daily flow, high and low flood pulse counts, DOC concentrations and water temperature. Compound-specific 13C analysis of PLFA showed that both bacterial and microeukaryotic stable carbon isotope ratios were heaviest in the spring and lightest in autumn or winter. Bacterial lipids were isotopically depleted on average by 2 - 5 / relative to δ13C of total organic carbon suggesting bacterial consumption of allochthonous organic matter, and enriched relative to δ13C algae-derived carbon source. In Chapter 4, heterotrophic microbes that metabolize humic DOM in a third-order stream were identified through trace-additions of 13C-labeled tree tissue leachate (13C-DOC) into stream sediment mesocosms. Microbial community structure was assessed using PLFA biomarkers, and metabolically active members were identified through 13C-PLFA analysis (PLFA-SIP). Comparison by PCA of the microbial communities in stream sediments and stream sediments incubated in both the presence and absence of 13C-DOC showed our mesocosm-based experimental design as sufficiently robust to investigate the utilization of 13C-DOC by sediment microbial communities. After 48 hours of incubation, PLFA-SIP identified heterotrophic α, β, and γ- proteobacteria and facultative anaerobic bacteria as the organisms primarily responsible for humic DOC consumption in streams and heterotrophic microeucaryotes as their predators. The evidence presented in this study shows a complex relationship between microbial community structure, environmental heterogeneity and utilization of humic DOC, indicating that humic DOC quality and quantity along with other hydro-ecological variables should be considered among the important factors that structure benthic microbial communities in lotic ecosystems.

Microbial Diversity and Ecosystem Functioning in Fragmented Rivers Worldwide

Microbial Diversity and Ecosystem Functioning in Fragmented Rivers Worldwide
Title Microbial Diversity and Ecosystem Functioning in Fragmented Rivers Worldwide PDF eBook
Author Lunhui Lu
Publisher Frontiers Media SA
Pages 188
Release 2023-11-27
Genre Science
ISBN 2832539874

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Dams or barriers are among the most significant anthropogenic threats to global freshwater ecosystems, although they provide invaluable services for shipping, hydropower generation, flood protection, and storage of drinking and irrigation water. River fragmentations due to dams and barriers lead the aquatic landscape into isolated river sections, resulting in hydromorphological discontinuities along longitudinal or lateral gradients. Fragmented river habitats are unstable. They experience uncertain disturbances in both time and space with random and complex hydrological and environmental processes, such as water flow, particulate matter sedimentation, reservoir regulation, and terrestrial input. The diversity, composition, functionality, and activity of microbial communities are important indicators of river ecosystem functions and services. Yet, river fragmentations are likely to disrupt and reconstruct microbial communities, redirecting the patterns of biogeochemical cycles of biogenic elements. Methodology, such as mathematical models, is still limited to describing and elucidating microbial processes under changing hydrological environments in the fragmented rivers. Thus, how do the riverine microbial communities and ecosystem functions respond to the fragmentation in rivers? This Research Topic represents a collective focus on microbial ecology, functional diversity, and new microbial modeling in fragmented rivers. We wish to present new findings in community assembly mechanisms, biotic interactions, functional diversity, and ecosystem functioning responses to the river fragmentations. New perspectives will also provide us with deep insights into the ecological effects of river fragmentation. This Research Topic aims to present the original research articles and reviews to provide new findings on microbial diversity and ecosystem functioning in fragmented rivers worldwide. We welcome original research, reviews, mini-reviews, opinions, methods, hypotheses and theories, and perspectives. The directions include but are not limited to the following aspects: - The continuum of the microbial community in responses to dams or barriers. - Novel microbial community assembly mechanisms, functional traits, and biotic interactions in fragmented rivers at local, regional, and global scales. - Functional genes, functional groups, and functional diversity in driving biogenic element cycles. - Mathematical modeling in aquatic microbial ecology.

Microbial Community Analysis

Microbial Community Analysis
Title Microbial Community Analysis PDF eBook
Author Thomas E. Cloete
Publisher IWA Publishing
Pages 108
Release 1997-01-01
Genre Science
ISBN 9781900222020

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Microbial Community Analysis surveys the vast amount of theoretical and practical knowledge on the design of biological treatment systems. It describes the different types of biological wastewater systems, the role of microbial diversity in these systems, and how this affects design and operation, methods for studying microbial community dynamics, and mathematical modelling of these systems. Contents Biological methods for the treatment of wastewaters Biodiversity and microbial interactions in the biodegradation of organic compounds Microbial population dynamics in biological wastewater treatment plants Molecular techniques for determining microbial community structures in activated sludge Principles in the modelling of biological wastewater treatment plants Practical considerations for the design of biological wastewater treatment systems Scientific and Technical Report No.5