Download or read book Cycling of Biogenic Manganese Oxides in a Model Microbial Predator prey System written by Carolyn Alexandra Zeiner and published by . This book was released on 2004 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geomicrobiology written by Henry Lutz Ehrlich and published by CRC Press. This book was released on 2008-12-22 with total page 630 pages. Available in PDF, EPUB and Kindle. Book excerpt: Uncovers the Key Role Microbes Play in the Transformation of Oxidizable and Reducible MineralsMany areas of geomicrobial processes are receiving serious attention from microbiologists, specifically the role microbes play in the formation and degradation of minerals and fossil fuels and elemental cycling. Most notably, the latest research finds that
Download or read book Engineered manganese redox cycling for utilisation of biogenic manganese oxides to remove micropollutants written by and published by . This book was released on with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of a Model to Predict Effects of Microbial Predation on Lead Phase Distribution and Toxicity written by Leslie Elizabeth Patton and published by . This book was released on 2007 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interactions between microbial predators and their prey can significantly influence the behavior of toxic trace metals. Metals associated with bacterial prey can be released into the dissolved phase following digestion by a predator, and/or metals can remain in the predator and potentially be transferred to the next level of the food chain. Toxic metal ions in the aqueous phase are also expected to modify the growth and predation rate of a microbial predator. A defined predator-prey system was developed to study metal behavior in simple microbial food chains using lead (Pb) as a representative metal. Desired features of this system were the ability to define the chemical speciation of dissolved metals as well as to distinguish between prey and predator-bound metals. Pseudomonas putida and the ciliate protozoan Tetrahymena thermophila were selected as representative bacterial prey and predator species, respectively. Batch reactors were used to measure microbial growth parameters, effects of prey density on predation and Pb phase distribution. A mathematical model was developed to describe predator-prey dynamics and their influence on the behavior and fate of Pb. Growth data were used to obtain model parameters, and model simulations for Pb fractionation were compared to experimental observations. The methodological studies demonstrated successful predator-prey separation techniques with little metal loss. Results of batch reactor experiments demonstrated that some kinetic parameters related to prey consumption and growth of T. thermophila are altered by Pb. Upon addition of predator to prey cells in equilibrium with dissolved Pb, dissolved and prey-bound Pb became associated with the predator through ingestion and adsorption. Ingested Pb was later excreted as a bound metal associated with T. thermophila waste matter. Experimental observations that did not match model predictions prompted further mathematical modeling of this predatorprey system. These simulations also explored Pb behavior under other hypothetical experimental conditions such as a chemostat reactor and a pulsed Pb dosing regime. The generality of the model was demonstrated by matching the trends in experimental data reported by other investigators for a different trace metal (Cd) in a different predator-prey system. (Abstract).
Download or read book Anaerobic Reduction of Manganese Oxides and Its Effect on the Carbon and Nitrogen Cycles written by Hui Lin and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The biogenic reduction of Mn(IV) oxides is one of the most favorable anaerobic electron transfer processes in aquatic systems and likely plays an important role in the redox cycle of both carbon and nitrogen in anaerobic environments; yet, the different pathways involved in the microbial transformation of Mn(IV) oxides remain unclear. The coupling between the reduction of Mn(IV) to Mn(II) and the oxidation of organic carbon to CO2 is largely catalyzed by microorganisms in various environments such as redox stratified water columns and sediments. The recent discovery that soluble Mn(III) exists in natural systems and is formed during biological oxidation of Mn(II) implies the possibility that Mn(III) is formed as an intermediate during the microbial reduction of Mn(IV). In this dissertation, mutagenesis studies and kinetic analysis were combined to study the mechanism of microbial reduction of Mn(IV) by Shewanella oneidensis MR-1, one of the most studied metal-respiring prokaryotes. We show for the first time that the microbial reduction of Mn(IV) proceeds step-wise via two successive one-electron transfer reactions with soluble Mn(III) as intermediate produced in solution. The point mutant strain Mn3, generated via random chemical mutagenesis, presents a unique phenotype that reduces solid Mn(IV) to Mn(III) but not to Mn(II), suggesting that these two reduction steps proceed via different electron transport pathways. Mutagenesis studies on various in-frame deletion mutant strains demonstrate that the reduction of both solid Mn(IV) and soluble Mn(III) occurs at the outer membrane of the cell and Mn(IV) respiration involves only one of the two potential terminal reductases (c-type cytochrome MtrC and OmcA) involved in Fe(III) respiration. Interestingly, only the second electron transfer step is coupled to the respiration of organic carbon, which opposes the long-standing paradigm that microbial reduction of Mn(IV) proceeds via the single transfer of two electrons coupled to the mineralization of carbon substrates. The coupling between anaerobic nitrification and Mn reduction has been demonstrated to be thermodynamically favorable. However, the existence of this process in natural system is still in debate. In this dissertation, characterization of coastal marine sediments was combined with laboratory incubations of the same sediments to investigate the effect of Mn oxides on the redox cycle of nitrogen. Our slurry incubations demonstrate that anaerobic nitrification is catalyzed by Mn oxides. In addition, mass balance calculations on NH4 link the consumption of NH4 to anaerobic ammonium oxidation in the presence of Mn oxides and confirm the occurrence of Mn(IV)-catalyzed anaerobic nitrification. The activity of anaerobic nitrification is greatly affected by the initial ratio of Mn(IV) to NH4+, the reactivity of Mn oxides, and the reducing potential of the system. Overall, Mn(IV)-catalyzed anaerobic nitrification may be an important source of nitrite/nitrate in anaerobic marine sediments and provide an alternative pathway for subsequent nitrogen losses in the marine nitrogen cycle.
Download or read book Reactivity of Biogenic Manganese Oxide for Metal Sequestration and Photochemistry written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Many microbes, including both bacteria and fungi, produce manganese (Mn) oxides by oxidizing soluble Mn(II) to form insoluble Mn(IV) oxide minerals, a kinetically much faster process than abiotic oxidation. These biogenic Mn oxides drive the Mn cycle, coupling it with diverse biogeochemical cycles and determining the bioavailability of environmental contaminants, mainly through strong adsorption and redox reactions. This mini review introduces recent findings based on quantum mechanical density functional theory that reveal the detailed mechanisms of toxic metal adsorption at Mn oxide surfaces and the remarkable role of Mn vacancies in the photochemistry of these minerals.
Download or read book Ecology Abstracts written by and published by . This book was released on 1991 with total page 802 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coverage: 1982- current; updated: monthly. This database covers current ecology research across a wide range of disciplines, reflecting recent advances in light of growing evidence regarding global environmental change and destruction. Major ares of subject coverage include: Algae/lichens, Animals, Annelids, Aquatic ecosystems, Arachnids, Arid zones, Birds, Brackish water, Bryophytes/pteridophytes, Coastal ecosystems, Conifers, Conservation, Control, Crustaceans, Ecosyst em studies, Fungi, Grasses, Grasslands, High altitude environments, Human ecology, Insects, Legumes, Mammals, Management, Microorganisms, Molluscs, Nematodes, Paleo-ecology, Plants, Pollution studies, Reptiles, River basins, Soil, TAiga/tundra, Terrestrial ecosystems, Vertebrates, Wetlands, Woodlands.
Download or read book Oceanic Abstracts with Indexes written by and published by . This book was released on 1983 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Practical Guide to Ecological Modelling written by Karline Soetaert and published by Springer Science & Business Media. This book was released on 2008-10-14 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mathematical modelling is an essential tool in present-day ecological research. Yet for many ecologists it is still problematic to apply modelling in their research. In our experience, the major problem is at the conceptual level: proper understanding of what a model is, how ecological relations can be translated consistently into mathematical equations, how models are solved, steady states calculated and interpreted. Many textbooks jump over these conceptual hurdles to dive into detailed formulations or the mathematics of solution. This book attempts to fill that gap. It introduces essential concepts for mathematical modelling, explains the mathematics behind the methods, and helps readers to implement models and obtain hands-on experience. Throughout the book, emphasis is laid on how to translate ecological questions into interpretable models in a practical way. The book aims to be an introductory textbook at the undergraduate-graduate level, but will also be useful to seduce experienced ecologists into the world of modelling. The range of ecological models treated is wide, from Lotka-Volterra type of principle-seeking models to environmental or ecosystem models, and including matrix models, lattice models and sequential decision models. All chapters contain a concise introduction into the theory, worked-out examples and exercises. All examples are implemented in the open-source package R, thus taking away problems of software availability for use of the book. All code used in the book is available on a dedicated website.
Download or read book Bioavailability of Contaminants in Soils and Sediments written by National Research Council and published by National Academies Press. This book was released on 2003-05-03 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bioavailability refers to the extent to which humans and ecological receptors are exposed to contaminants in soil or sediment. The concept of bioavailability has recently piqued the interest of the hazardous waste industry as an important consideration in deciding how much waste to clean up. The rationale is that if contaminants in soil and sediment are not bioavailable, then more contaminant mass can be left in place without creating additional risk. A new NRC report notes that the potential for the consideration of bioavailability to influence decision-making is greatest where certain chemical, environmental, and regulatory factors align. The current use of bioavailability in risk assessment and hazardous waste cleanup regulations is demystified, and acceptable tools and models for bioavailability assessment are discussed and ranked according to seven criteria. Finally, the intimate link between bioavailability and bioremediation is explored. The report concludes with suggestions for moving bioavailability forward in the regulatory arena for both soil and sediment cleanup.
Download or read book Size Limits of Very Small Microorganisms written by National Research Council and published by National Academies Press. This book was released on 1999-10-13 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: How small can a free-living organism be? On the surface, this question is straightforward-in principle, the smallest cells can be identified and measured. But understanding what factors determine this lower limit, and addressing the host of other questions that follow on from this knowledge, require a fundamental understanding of the chemistry and ecology of cellular life. The recent report of evidence for life in a martian meteorite and the prospect of searching for biological signatures in intelligently chosen samples from Mars and elsewhere bring a new immediacy to such questions. How do we recognize the morphological or chemical remnants of life in rocks deposited 4 billion years ago on another planet? Are the empirical limits on cell size identified by observation on Earth applicable to life wherever it may occur, or is minimum size a function of the particular chemistry of an individual planetary surface? These questions formed the focus of a workshop on the size limits of very small organisms, organized by the Steering .Group for the Workshop on Size Limits of Very Small Microorganisms and held on October 22 and 23, 1998. Eighteen invited panelists, representing fields ranging from cell biology and molecular genetics to paleontology and mineralogy, joined with an almost equal number of other participants in a wide-ranging exploration of minimum cell size and the challenge of interpreting micro- and nano-scale features of sedimentary rocks found on Earth or elsewhere in the solar system. This document contains the proceedings of that workshop. It includes position papers presented by the individual panelists, arranged by panel, along with a summary, for each of the four sessions, of extensive roundtable discussions that involved the panelists as well as other workshop participants.
Download or read book Modern Biogeochemistry written by Vladimir N. Bashkin and published by Springer Science & Business Media. This book was released on 2006-12-29 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is aimed at generalizing the modern ideas of both biogeochemical and environmental risk assessment that have been developed in recent years. Only a few books are available in this interdisciplinary area, since most deal mainly with various technical aspects of ERA description and calculations. This text aims at supplementing the existing books by providing a modern understanding of mechanisms responsible for ecological risks for human beings and ecosystems.
Download or read book Atmospheric Evolution on Inhabited and Lifeless Worlds written by David C. Catling and published by Cambridge University Press. This book was released on 2017-04-13 with total page 595 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive and authoritative text on the formation and evolution of planetary atmospheres, for graduate-level students and researchers.
Download or read book Primary Productivity and Biogeochemical Cycles in the Sea written by Paul G. Falkowski and published by Springer Science & Business Media. This book was released on 2013-11-22 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biological processes in the oceans play a crucial role in regulating the fluxes of many important elements such as carbon, nitrogen, sulfur, oxygen, phosphorus, and silicon. As we come to the end of the 20th century, oceanographers have increasingly focussed on how these elements are cycled within the ocean, the interdependencies of these cycles, and the effect of the cycle on the composition of the earth's atmosphere and climate. Many techniques and tools have been developed or adapted over the past decade to help in this effort. These include satellite sensors of upper ocean phytoplankton distributions, flow cytometry, molecular biological probes, sophisticated moored and shipboard instrumentation, and vastly increased numerical modeling capabilities. This volume is the result of the 37th Brookhaven Symposium in Biology, in which a wide spectrum of oceanographers, chemists, biologists, and modelers discussed the progress in understanding the role of primary producers in biogeochemical cycles. The symposium is dedicated to Dr. Richard W. Eppley, an intellectual giant in biological oceanography, who inspired a generation of scientists to delve into problems of understanding biogeochemical cycles in the sea. We gratefully acknowledge support from the U.S. Department of Energy, the National Aeronautics and Space Administration, the National Science Foundation, the National Oceanic and Atmospheric Administration, the Electric Power Research Institute, and the Environmental Protection Agency. Special thanks to Claire Lamberti for her help in producing this volume.
Download or read book Principles of Terrestrial Ecosystem Ecology written by F Stuart Chapin III and published by Springer Science & Business Media. This book was released on 2006-04-10 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: Features review questions at the end of each chapter; Includes suggestions for recommended reading; Provides a glossary of ecological terms; Has a wide audience as a textbook for advanced undergraduate students, graduate students and as a reference for practicing scientists from a wide array of disciplines
Download or read book Guide to Best Practices for Ocean Acidification Research and Data Reporting written by and published by . This book was released on 2011 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Prokaryotes written by Edward F. DeLong and published by Springer. This book was released on 2014-10-13 with total page 567 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Prokaryotes is a comprehensive, multi-authored, peer reviewed reference work on Bacteria and Achaea. This fourth edition of The Prokaryotes is organized to cover all taxonomic diversity, using the family level to delineate chapters. Different from other resources, this new Springer product includes not only taxonomy, but also prokaryotic biology and technology of taxa in a broad context. Technological aspects highlight the usefulness of prokaryotes in processes and products, including biocontrol agents and as genetics tools. The content of the expanded fourth edition is divided into two parts: Part 1 contains review chapters dealing with the most important general concepts in molecular, applied and general prokaryote biology; Part 2 describes the known properties of specific taxonomic groups. Two completely new sections have been added to Part 1: bacterial communities and human bacteriology. The bacterial communities section reflects the growing realization that studies on pure cultures of bacteria have led to an incomplete picture of the microbial world for two fundamental reasons: the vast majority of bacteria in soil, water and associated with biological tissues are currently not culturable, and that an understanding of microbial ecology requires knowledge on how different bacterial species interact with each other in their natural environment. The new section on human microbiology deals with bacteria associated with healthy humans and bacterial pathogenesis. Each of the major human diseases caused by bacteria is reviewed, from identifying the pathogens by classical clinical and non-culturing techniques to the biochemical mechanisms of the disease process. The 4th edition of The Prokaryotes is the most complete resource on the biology of prokaryotes. The following volumes are published consecutively within the 4th Edition: Prokaryotic Biology and Symbiotic Associations Prokaryotic Communities and Ecophysiology Prokaryotic Physiology and Biochemistry Applied Bacteriology and Biotechnology Human Microbiology Actinobacteria Firmicutes Alphaproteobacteria and Betaproteobacteria Gammaproteobacteria Deltaproteobacteria and Epsilonproteobacteria Other Major Lineages of Bacteria and the Archaea
