Download or read book Bacterial Community Composition in Stream Biofilms is Influenced by Algal Response to Varying Light and Phosphorus Ratios written by Yu-rui Chang and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Strong correlations between bacterial communities and algal seasonal succession have been previously observed. In aquatic systems, dissolved organic carbon derived by algae is an important resource for bacteria. Light and phosphorus availability are two factors that influence biomass and abundance of algae, and the changes will be reflected in the bacterial portion of the microbial community. Glycolate is an algal-specific exudate produced under excess light conditions. Glycolate uptake by bacteria has been shown to correlate with algal primary productivity. Bacterial populations that utilize glycolate possess the gene, glycolate oxidase subunit D (glcD). This gene was used as a marker to identify changes in specific bacterial populations that respond to algal exudates. In this study, development of periphyton biofilms in an experimental stream system was monitored across different light and phosphorus levels. Samples were collected every two days for community and chemistry analyses. Bacterial communities were monitored using DNA fingerprinting techniques based on ribosomal RNA genes and the glcD gene. We demonstrated that bacterial community composition changed significantly over the course of biofilm development, and light and phosphorus availability contributed to those differences in community composition. Our results suggest that a strong coupling between carbon flow and bacterial community composition. These results increase our understanding of the ecological drivers that impact benthic biofilm communities that carry out transformation of nutrients in streams.

Download or read book River Biofilm Structure and Function in a Resource Landscape Modified by Agriculture written by Hannah M. Fazekas and published by . This book was released on 2018 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anthropogenic alterations to nitrogen, carbon, and phosphorus bioavailability have increased the flux of these resources into the biosphere and altered stream ecosystem function. Streams modify the transport of these resources to receiving ecosystems through uptake, transformation, and mineralization. Understanding how streams process carbon, nitrogen, and phosphorus can provide insight about how stream ecosystems function in landscapes where human modification is inescapable. I investigated how land use in agricultural regions affect resource availability to primary producers and consumers and the subsequent impact on stream processes. I surveyed headwater streams in three Lake Erie watersheds to determine spatiotemporal nutrient limitation of attached algae. I found that low-order streams exhibit phosphorus limitation and the severity of phosphorus limitation was greatest post-fertilizer application when the imbalance between water column nitrogen: phosphorus concentrations was greatest. These results suggest that biofilm nutrient uptake responded to landscape level influences and attached algae actively sequestered phosphorus from the water column. Agriculture alters the availability of carbon through modification of riparian vegetation. I used genomic techniques to describe longitudinal changes in microbial community composition along a stream with headwaters that lacked riparian vegetation due to row crop agriculture but the width of the forested riparian area increased downstream. The relative abundance of the most abundant microbial phyla varied along physical and chemical (light, phosphorus concentration) gradients. Land use affected physical-chemical characteristics of the river, which in turn, influenced sediment microbial community composition. The removal of riparian forested vegetation leads to increased light availability to attached algae. I investigated the effect of attached algal productivity on consumers across an experimental gradient in light intensity. Attached algal productivity and consumer production were coupled across the light gradient. I also studied how land use influenced carbon resource use by common macroinvertebrate functional feeding groups in Midwestern streams. I found that invertebrates consistently used attached algal carbon. This reliance was not affected by riparian vegetation nor the percent of the watershed dedicated to agriculture. Food web structure remained similar across the gradient in land use. This work demonstrates that attached assemblages in streams respond to landscape level processes that propagate to consumers.

Download or read book Microbial Ecology of Phototrophic Biofilms written by Guus Roeselers and published by Guus Roeselers. This book was released on 2007 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biofilms are layered structures of microbial cells and an extracellular matrix of polymeric substances, associated with surfaces and interfaces. Biofilms trap nutrients for growth of the enclosed microbial community and help prevent detachment of cells from surfaces in flowing systems. Phototrophic biofilms can best be defined as surface attached microbial communities mainly driven by light as the energy source with a photosynthesizing component clearly present. Eukaryotic algae and cyanobacteria generate energy and reduce carbon dioxide, providing organic substrates and oxygen. The photosynthetic activity fuels processes and conversions in the total biofilm community, including the heterotrophic fraction. This thesis starts with a brief introduction in the ecology of phototrophic biofilms and discusses their actual and potential applications in wastewater treatment, bioremediation, fish-feed production, biohydrogen production, and soil improvement and their role in biofouling. The next chapter describes the diversity of phototrophic bacteria in hot spring microbial mats found on the east coast of Greenland. In this study we utilized a polyphasic approach using a combination of isolation techniques, microscopic observation of morphological features, and cultivation-independent molecular methods. We observed a relationship between the cyanobacterial community composition and the in situ temperatures of different microbial mat parts. Chapter 4 focuses on the successional changes in community composition of freshwater phototrophic biofilms growing under different light intensities. Our results suggest that surface colonization by heterotrophic pioneers facilitates the development of phototrophic biofilms. In Chapter 5 we compared the community composition of phototrophic biofilms cultivated in three microcosm systems operated under identical conditions but placed in different laboratories. Denaturing Gradient Gel Electrophoresis (DGGE) analysis of both 16S and 18S rRNA gene fragments showed that the communities developed differently in terms of species richness and community composition. Chapter 6 demonstrates that nifD gene sequences, coding for a nitrogenase subunit, can be used to detect and identify diazotrophic cyanobacteria in natural communities. PCR products generated using primers homologous to conserved regions in the cyanobacterial nifD genes were subjected to DGGE and clone library analysis in order to determine the genetic diversity of diazotrophic cyanobacteria in environmental samples. In the last chapter we describe the development of PCR primers targeting conserved regions within the cyanobacterial hupS gene family. This gene is involved in the hydrogen metabolism of diazotrophic microorganisms. We analyzed hupS diversity and transcription in cultivated phototrophic biofilms by the direct retrieval and analysis of mRNA that was reverse transcribed, amplified with hupS specific primers, and cloned. Overall, the community composition and species richness of phototrophic biofilms was shown to be highly variable. Cultivation-independent molecular methods proved very useful to study diversity and function in phototrophic biofilms.

Download or read book The Interrelation of Carbon Phosphorus in Regulating Heterotrophic and Autotrophic Populations in Aquatic Ecosystems written by Pat C. Kerr and published by . This book was released on 1970 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Micro ecology of Stream Biofilm Dynamics Environmental Drivers Successional Processes and Forensic Applications written by Jennifer M. Lang and published by . This book was released on 2015 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microbial activity has an essential role in ecosystem processes, and in stream ecosystems, biofilms are the base of the food web that is fueled by photosynthesis and they are integral to nutrient processing. Stream biofilms are microbial communities of algae, bacteria, fungi, and protozoa encased in an extracellular polymeric substance (EPS) (molecules secreted by the microbes) that are attached to a substrate (e.g. rocks, leaves) in an aqueous environment. The substrate categorizes the biofilm, and organic matter like leaves and carrion such as salmon carcasses are important substrates for nutrient dynamics. In special instances, human remains may be deposited into streams and colonized by biofilms; therefore, assessing these biofilms can have direct application to the forensic sciences. Stream ecologists have extensively investigated how environmental factors influence algal community composition, while environmental microbiologists have focused on the role of bacterial communities in nutrient dynamics. My dissertation marries these two approaches by considering biofilm communities as a functioning ecosystem and uses ecological theory as a framework to understand the dynamics of this micro-ecosystem. This framework uses aspects from landscape ecology within a larger context of community ecology to explain how the development of biofilm communities is altered by environmental factors. In addition, this framework was used to investigate biofilm development on carrion (dead animal) in a forensic science context.

Download or read book The Microbial Ecology of Stream Biofilms written by Kelly Michelle Roberts and published by . This book was released on 2011 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Oceanographic and Biological Aspects of the Red Sea written by Najeeb M.A. Rasul and published by Springer. This book was released on 2018-12-06 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book includes invited contributions presenting the latest research on the oceanography and environment of the Red Sea. In addition to covering topics relevant to research in the region and providing insights into marine science for non-experts, it is also of interest to those involved in the management of coastal zones and encourages further research on the Red Sea

Download or read book Understanding the Impacts of Organic Matter on Microbial Biofilms in Engineered Drinking Water Systems written by Lei Li and published by . This book was released on 2020 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: The increasing occurrence and severity of cyanobacterial harmful algal blooms (HABs) in freshwater have continuously challenged the safe drinking water supply. During HAB, public attention mainly focuses on the cyanotoxins, which associated with health issues, while HAB also generated massive amounts of algal cells, increasing the loading of algal organic matter (AOM) in the drinking water treatment plants (DWTPs). AOM is an algae-derived autochthonous natural organic matter (NOM), which contains high fraction of hydrophilic and nitrogenous compounds. Conventional treatment processes, comprised of coagulation, sedimentation, and granular media filtration, are known to be ineffective in completely removing NOM, including AOM [1, 2]. Although ozone has been widely adopted by water utilities to break down complex organic compounds and reduce DBP formation, ozonation practices can adversely increase concentrations of assimilable organic carbon (AOC), which in turn can be rapidly utilized and support biofilm growth in downstream filters and drinking water distribution systems [3, 4]. Currently, remain largely unknown for the growth of biofilms under the impacts of different NOM, including AOM in the filters and drinking water distribution systems (DWDSs). Therefore, the main research goal of this study is to investigate the impacts of organic matter on microbial biofilms in engineered drinking water systems (EDWSs). Specifically, the first objective of this study aimed to examine how the assembly processes and their associated factors (e.g., influent characteristics, biological interactions) drive the temporal dynamics of bacterial communities in full-scale BAC filters, which underwent ozone implementation to better handle the adverse effects of HABs. The obtained results revealed that along with the increase of bacterial taxonomic richness and evenness, stochastic processes became more crucial to determine the bacterial community assembly in the summer and autumn after ozone implementation. Moreover, their corresponding networks possessed simple network structures with lower modularity than other seasons, which implied lesser biological interactions among bacterial populations. Among the monitored physiochemical properties of filter influents, temperature and nutrient bioavailability (i.e., AOC concentrations) as well as biological interactions can be crucial drivers that impact the balance between these two processes and the taxonomic diversity of bacterial communities in BAC filters. The second objective of this study was to examine the effects of two widely present NOM, treated AOM and humic substances (HS), on biofilm development under unchlorinated DWDS conditions. Although great efforts have been made to remove NOM in DWTPs, remaining NOM still exists in the filter effluent and subsequently enter DWDSs. This unremoved NOM can support the growth of microbial biofilms in DWDS. Thus, the impact of AOM and HS on the formation, chemical composition, and microbial community structures of biofilms was evaluated. The 16S rRNA gene sequencing analyses revealed that the bacterial communities in biofilms were clustered with the organic matter types in bulk water, where Family Comamonadaceae was the most dominant but showed different temporal dynamics depending on the organic matter characteristics in bulk water. Higher diversity was observed in the biofilms grown in AOM-impacted bulk water (BFAOM) than biofilms grown in HS-impacted (BFHS) and R2A-impacted bulk water (BFR2A) as the biofilms matured. In addition, some taxa (e.g., Rhodobacteraceae, and Sphingomonadaceae) were enriched in BFAOM compared to BFHS and BFR2A. The biofilm image analysis results indicated that compared to BFHS, BFAOM and BFR2A had relatively thinner and heterogeneous physical structures with lower amounts of cell biomass, extracellular polymeric substances (EPS), and higher EPS protein/polysaccharide ratios. The third objective of this study was to elucidate how different types of organic matter, including AOM and HS, affect biomolecular compositions of biofilms and subsequent DBP formation. In order to control biofilm formation in DWDS, water utilities apply disinfectants such as chlorine or monochloramines. However, these applied disinfectants can lead to the formation of toxic DBPs due to the presence of organic-rich substances within biofilms. Therefore, the impact of organic matter composition on biomulecular composition of biofilms and their correlations with DBP formation were explored. The obtained results indicated that all biofilm samples comprised mostly of protein-like components (~90%), and to a lesser extent, humic-like components (~10%). Strong correlations were generally found between tryptophan-like substances and the studied DBP formation (R2min ≥ 0.76, P

Download or read book The Interrelation of Carbon and Phosphorous in Regulating Heterotrophic and Autotrophic Populations in Aquatic Ecosystems written by United States. Federal Water Quality Administration and published by . This book was released on 1971 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Understanding the Impacts of Harmful Algal Blooms on Biologically active Filtration for Drinking Water Treatment written by Youchul Jeon and published by . This book was released on 2020 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: Harmful algal blooms (HABs) dominated by toxic cyanobacteria have been increasingly detected in water bodies worldwide. During such blooms, cyanobacterial cells may produce and release undesirable algal metabolites such as cyanotoxins and taste and odor causing compounds, which can severely impair water quality. Among the cyanotoxins produced by different cyanobacteria, the most prevalent in freshwater systems are microcystins (MCs). Microcystin-LR (MC-LR), one of the most toxic and frequently detected among microcystin congeners, is a hepatotoxin that can be lethal. In addition, cyanobacterial cells release algal organic matter (AOM) containing a wide spectrum of components such as amino acids, peptides, proteins, and polysaccharides. These are known to serve as precursors for disinfection byproducts (DBPs). However, much remains unknown about how HABs affect drinking water treatment processes, especially a biologically-active filtration (BAF) which is considered as a last barrier in a drinking water treatment plant (DWTP) and plays an important role in removing various natural organic matter and meditating the source water's ecological influence on tap water bacterial community. Therefore, the main research goal of this study is to investigate the impacts of HABs on a biological filtration system in a DWTP. Specifically, the first objective of this study aimed to examine the influence of severe HABs on microbial communities in a full-scale BAF for drinking water treatment. The obtained results showed that microbial diversity in BAF significantly decreases during severe HAB due to the predominance of bloom-associated bacteria (e.g., Sphingopyxis, Porphyrobacter, and Sphingomonas). In addition, severe HAB results in enhanced BAF community function utilizing fatty and amino acids, and modularity, suggesting a presence of biodegradable compounds from AOM. Lastly, the higher relative importance of stochastic processes was observed during the severe HAB than the mild HAB, while stochastic processes were dominant BAF bacterial community assembly. The second objective of this study was to assess the impact of AOM on the performance, MC-LR removal, and biofilms of BAF. Based on the component analysis (excitation and emission matrix analysis) results, terrestrial humic-like substances showed the highest removal among all the identified AOM components and were strongly correlated to MC-LR removal. In addition, reduced empty bed contact time and deactivation of biofilms significantly decreased BAF performances for both AOM and MC-LR. The active biofilm, bacterial community structure, and mlrA gene (involved in microcystin degradation) abundance demonstrated that bacterial biofilm composition responded to AOM and MC-LR, in which Rhodocyclaceae, Saprospiraceae, and Comamonadaceae were dominant. The third objective of this study was to understand the effects of bioagumentation on the removal of MC-LR and bacterial community structure in BAF for drinking water treatment. The non-bioaugmented column showed less than 1 μg/L of MC-LR in effluent after two weeks of operation. In contrast, no improved removal efficiency of MC-LR was observed in the bioaugmented column and more than 1 μg/L of MC-LR was continuously detected in effluent. During the operation, regular backwashing had no significant effect on the MC-LR removal performance in both columns. On the basis of mlrA gene abundance and 16S rRNA amplicon sequencing, the decreasing pattern of Sphingopyxis sp. IM-1 abundance was observed in every backwashing. In addition, indigenous bacterial groups (e.g., the family Burkholderiaceae and Methylotenera) were positively correlated with MC-LR removal in the columns. Phylogenetic molecular ecological networks showed that the bioaugmented column possessed more complex network and negative links than the control column, indicating that bioaugmentation caused a negative influence on indigenous bacterial community.

Download or read book The Effects of Low level Pharmaceuticals on Stream Biofilm Structure and Function Across a Land use Gradient in Streams of the Huron River Watershed written by Elizabeth Mae Stover and published by . This book was released on 2020 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pharmaceuticals and personal care products (PPCPs) are a contaminant class of worldwide concern. Their environmental omnipresence indicates they may be a potential source of global change, and ecosystem-scale impacts at non-lethal levels have not been fully explored. We used stream biofilms to assess ecosystem responses to PPCPs. Biofilms were cultivated in streams draining areas of different land use and then exposed to triclosan, diphenhydramine, and sulfamethoxazole-trimethoprim treatments. We found evidence that low levels of these PPCPs affected some, but not all, aspects of biofilm processes and bacterial community composition. Bacterial carbon uptake was reduced (p = 0.06) and we found shifts in biofilm community composition following treatments. However, maximum photosynthetic efficiency, decomposition, and microbial physiological profiles showed no significant effect of PPCPs. Still, changes in bacterial activity and composition suggest that PPCPs may act as ecological disruptors at low levels, and further research is needed to assess ecosystem-scale effects

Download or read book Response of Stream Biofilms to Pulsed Versus Steady state Phosphorus Additions written by Aaron M. Gordon-Weaver and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The purpose of this study was to compare the effects of a steady-state P [phosphorus] release versus successive pulse events on algae-dominated biofilms colonizing artificial streams."--leaf 2.

Download or read book The Effects of Light Level and Temperature on Freshwater Microbial Biomass Production Enzyme Activity and Community Composition written by Joel Bonney and published by . This book was released on 2020 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: Algae can stimulate the production of heterotrophic microbes in periphyton communities, but the synergistic effects of light and temperature on this phenomenon are not well understood and have implications on carbon cycling and energy flow. We employed recirculating mesocosms held at different temperatures and light levels and filled with Typha litter and attached microbes to assess these effects. Heterotrophic microbial production was greater in the presence of light, as were some periphytic enzyme activities. Few response variables increased in a near-linear fashion with ascending temperature, suggesting different temperature optima. The strength of heterotrophic microbial production responses to algal photosynthesis did not vary with respect to temperature, but some enzyme activities did. The magnitude of light stimulation of bacterial production and several enzymatic activities were positively correlated, suggesting a similar driving mechanism. These findings advance our limited understanding of the synergistic effects of light and temperature on microbial communities..

Download or read book Microbiological Aspects of Biofilms and Drinking Water written by Steven Lane Percival and published by CRC Press. This book was released on 2000-05-23 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of biofilms and their role in public health - particularly drinking water - is often overlooked. Ideal for anyone interested in water related issues, Microbiological Aspects of Biofilms and Drinking Water presents an overview of the public health effects associated with drinking water. It highlights the microbiological aspects relat

Download or read book Freshwater Microbiology written by David C. Sigee and published by John Wiley & Sons. This book was released on 2005-09-27 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique textbook takes a broad look at the rapidly expanding field of freshwater microbiology. Concentrating on the interactions between viruses, bacteria, algae, fungi and micro-invertebrates, the book gives a wide biological appeal. Alongside conventional aspects such as phytoplankton characterisation, seasonal changes and nutrient cycles, the title focuses on the dynamic and applied aspects that are not covered within the current textbooks in the field. Complete coverage of all fresh water biota from viruses to invertebrates Unique focus on microbial interactions including coverage of biofilms, important communities on all exposed rivers and lakes. New information on molecular and microscopical techniques including a study of gene exchange between bacteria in the freshwater environment. Unique emphasis on the applied aspects of freshwater microbiology with particular emphasis on biodegradation and the causes and remediation of eutrophication and algal blooms.

Download or read book Control of Biofilm Growth in Drinking Water Distribution Systems written by and published by . This book was released on 1992 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Use of Stream Biofilm Microbial Communities and Associated Metals as Indicators of Urban Runoff Impact on Freshwater Ecosystems written by Pierre-Yves Ancion and published by . This book was released on 2010 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The main focus of this project was to investigate how anthropogenic activities affect stream biofilm microbial communities and to assess the potential uses of biofilms as indicators of freshwater ecosystem health. The work improves our understanding of the impact of urbanisation on stream ecosystems and provides innovative techniques to assess this impact more accurately. Stream biofilms are the complex aggregation of microorganisms, covering almost every surface in freshwater environments. They play key roles in stream ecosystems and are grazed by many other organisms. Therefore, the potential impact of urbanisation on biofilm microbial communities could alter the functions of biofilms and affect the whole stream ecosystem. A wide range of experiments was conducted in both flow chamber microcosms and natural stream environments to investigate the impact of urban runoff on microbial community structure and composition. Using community fingerprinting techniques such as Terminal-Restriction Fragment Length Polymorphism and Automated Ribosomal Intergenic Spacer Analysis, as well as sequencing of bacterial 16S rRNA genes, we investigated changes occurring in biofilm bacterial and ciliate protozoan communities under exposure to urban contaminants. Flow chamber experiments revealed that significant differences in the structure of the microbial community could be detected within only a few days of exposure to urban runoff contaminants and remained detectable weeks after transfer to uncontaminated water. The rapid and persistent changes highlight the sensitivity of microbial communities and suggest that natural biofilm communities frequently exposed to urban runoff are significantly altered. Experiments carried out in natural streams confirmed the differences in composition and tolerance to contaminants between biofilm communities from preserved and impacted streams, suggesting critical implications for the whole stream ecosystem. The structure and composition of microbial communities associated with biofilms result from the influence of past and present environmental conditions and therefore constitute potential integrative indicators of stream health. Rapid changes in bacterial and ciliate community structure during exposure to metal contaminants demonstrated the sensitivity of these communities and their potential use as indicators of the influence of urban areas on stream ecosystem. Additional investigation conducted in natural streams indicated that bacterial and ciliate communities can reveal changes occurring along an urbanisation gradient and confirmed their reliable use as ecological bio-indicators. These novel indicators were implemented successfully to investigate the efficiency of an enclosed stormwater treatment system where traditional biological indicators such as benthic macroinvertebrates are not available. Results revealed the successful improvement of water through the treatment train and the minimal impact on the receiving creek. As biofilms are sessile structures, they may also accumulate urban contaminants and could form a critical link in the movement of urban contaminants from abiotic to biotic components of the stream. Therefore, the absorption and release rates of metals (Zn, Cu and Pb) in biofilms were investigated. Results revealed the fast accumulation of metals in the matrix during the first few days. High enrichment factors were recorded between the biofilm wet weight and the water, reaching 500:1 for zinc, 1500:1 for copper and 6000:1 for lead after 21 days of exposure. During recovery in uncontaminated water, metals were retained in the biofilm and 10 to 16 % of zinc and copper accumulated during exposure still remained in the biofilm after 14 days of recovery. The release of lead was even slower and more than 35 % of accumulated lead remained in the biofilm after 14 days of recovery. Investigation in natural streams confirmed the accumulation of metals in biofilms from urban streams and highlighted the potential risk for organisms at a higher trophic level. These results suggested that metals associated with biofilms could provide a highly relevant indicator of the presence of metals in freshwater systems at concentrations detrimental to aquatic biota. Using biofilm bacterial, ciliate and macro-invertebrate communities as bio-indicators, the relevance of biofilm associated metals (As, Cd, Cr, Cu, Pb, Ni and Zn) was investigated and compared to sediment associated metals. A greater proportion of the changes occurring in each of the communities could be explained by metal concentrations in biofilm than in sediments confirming the ecological relevance of biofilm associated metals. This project provides an insight into the effect of urban contaminants on stream microorganisms and contributes to the understanding of how urbanisation affects the entire stream ecosystem. Novel tools emerging from the use of biofilm as an indicator of stream health will assist land planners, aquatic resource managers and decision makers by facilitating better assessment of urban influences on aquatic environments"--Abstract.