Biochemical Responses Of Arctic Soil Communities To Anthropogenic Stress

We are living in the era of climate change which becomes more complicated whenever some new environmental issue emerges only to get linked with this already existing challenge. Engineered nanoparticle (NP) contamination is of such issue which may become a major environmental problem under some circumstances in the decades to come. NP-based technologies have proven themselves useful and have the potential for greater promise, but they could become more than a nuisance. Unfortunately, very limited information is available on the environmental impacts of NPs in general and soil in particular. In this thesis, I examined the impact of NPs on soil microbial communities and by trying to avoid the presence of existing NPs I used soil from arctic regions. To examine the effect of another anthropogenic change on the same soil, I investigated the impacts of freeze-thaw cycles (FTCs). This thesis demonstrated that Ag-NPs and Cu-NPs cause a shift in microbial communities. The use of culture-dependent and culture-independent assessment techniques for microbial communities inspired the development of a toxicity indicator. This tool assigned the highest toxicity index to Ag-NPs and a low toxicity to SiO2-NPs. Supporting in vitro studies confirmed that Bradyrhizobium canariense was particularly sensitive towards Ag-NPs. Further analysis showed that a mixture of Ag-, Cu-, and SiO2-NPs were toxic. FTCs were also a significant stress; they had a differential impact upon soil communities derived from different arctic sites. My results suggest that the impact of climate change at high latitudes may not be predictable. Finally, I used a FTC regime shown not have an impact on low arctic sites and compared two different concentrations of Ag-NPs and Ag-microparticles and validated the higher toxicity impact of Ag-NPs on both bacterial and fungal communities. Taken together, these findings represent an initial attempt to try to understand the impacts of two stresses attributable to human activities on arctic soils, soils that are crucial to the health of our planet.

In this dissertation several research studies are discussed that characterize the effects of anthropogenic, or human-induced, stress on both ammonia-oxidizing and total bacterial soil microbial communities. The disturbances of land-use change in tropical, South American rainforests and artificial warming and nitrogen (N) fertilization in temperate, North American forests were investigated as these disturbances represent past and current disturbances caused by human landscape alteration and climate change. Initially, the response of soil ammonia-oxidizing microbial communities to land-use change from primary rainforest to pasture and, finally, back to secondary forest was determined. Next, these analyses of land-use change effects were expanded to the total bacterial community in these rainforest soils sampled annually for three years. Lastly, the effects of increasing soil temperature and N-deposition on ammonia-oxidizing microbial communities in temperate forests were characterized. Land-use change affected ammonia-oxidizing communities in tropical soils. Both the abundance of ammonia-oxidizer marker genes and their community structure shifted due to land-use changes. Interestingly, phylogenetic analyses showed that community structural changes in ammonia-oxidizing thaumarchaea are driven by a shift away from primary rainforest, old pasture, and secondary forest clusters to separate clusters for young pasture. Additionally, there was a nearly complete disappearance in young pasture, old pasture, and secondary forest sites of a thaumarchaeal ammonia-oxidizing genus, the Nitrosotalea. We found that many of the bacterial community responses to land-use change stayed consistent between land-use types across all three years, especially in regards to OTU richness and Faith's phylogenetic diversity. Bacterial community turnover, or distance-decay, was significantly greater (P 0.05) in forests compared to pastures for two out of three years sampled. Lastly, two bacterial species, Rhodomicrobium udaipurense and Anaeromyxobacter dehalogens, were found to be exclusive indicator species for the pasture land-use type across all sampling time points. Finally, when investigating the effects of increasing soil temperatures and N-deposition rates on temperate forest soil N-cycling, potential N-mineralization and nitrification rates and chitinase enzyme activity showed no difference between treatments (P 0.05). Bacterial, fungal, and archaeal rRNA genes and thaumarchaeal amoA genes showed no significant difference between treatments. There were significant differences in ammonia-oxidizer community structure between control and heated plus nitrogen treatments. The majority of archaeal ammonia-oxidizer species were most closely related to Nitrosotalea and Nitrososphaera spp. However, the organic horizon in the heated plus nitrogen treatment was dominated by sequences most closely related to Nitrosopumilus maritimus. Taken together, these results can provide a conceptual foundation as to how anthropogenic stressors can alter microbial communities in tropical and temperate forests soils. These communities are critical to global biogeochemical cycling and climate regulation. By charactering how these communities respond to various anthropogenic stressors, the scientific community can begin to use this information to develop more holistic biogeochemical models to predict shifts in nutrient flow and greenhouse gas production.

V. 1 - Natural and anthropogenic organics; v. 2 - Metals, other inorganics, and microbial activities. General soil quality as influenced by interactions of soil minerals with organics and microorganisms: Organic-inorganic interections in soils and their effects on soil quality; Sorption phenomena between inorganic and organic compounds in soils: impacts on transformation processes; Role of aluminium and iron in the accumulation of organic matter in soils with variable charge; Sorption of ions by soil organic matter and clay-organics at low ionic strength; Water potential, soil microhabitats, and microbial development; Effect of citric acid on interlayer adsorption of hydroxy-aluminosilicate ions by montmorillonite; Microbial oxidation of pyrites in relation to its efficiency in alkali soil reclamation; Modification of gelation properties of colloidal solids from oil sands: extraction impact on fine tailings formation; Position paper of part I; Transformations of natural and anthropogenic organic compounds as affected by soil minerals and microorganisms: Natural organics; Recent advances in organomineral interactions: implications for carbon cycling and soil structure; The role of short-range ordered mineral colloids in abiotic transformations of organics components in the environment; Influence of pyrogallol on the catalytic action of iron and managenese oxides in amino acid transformation; Photochemical effect on the abiotic transformations of polyphenolics as catalyzed by Mn(IV) oxide; Potential of the supercitical fluid extraction technique for characterizing organic-inorganic interactions in soils; Dissolution and fractionation of calcium-bound and iron-and aluminium-bound humus in soils; Rhe quality of soil organic matter as characterized by soil CPMAS C-NMR, and Py-FIMS; Extracellular polysaccharides: an interface between microorganisms and soil constituents; Low-molecular-weigh aliphatic carboxylic acids in some andisols of Japan; Relationship between organic acids and microorganisms on a kong-term cropping site in southeastern Australia; Effect of the addition of plant residues on the mineralization of sulfur in Costa Rican soils; Anthropogenic organics: Sorption and biodegradation of organic contaminants in soils: conceptual representations of process coupling; The role of dissolved metals and metal-containing surfaces in catalyzing the hydrolysis of organic pollutants; The role of abiotic and biotic catalysts in the transformation of phenolic compounds; The role of abiotic interections with humic substances on the environmental impact of organic pollutants; Adsorption mechanisms and abiotic catalytic transformations of some agrochemicals by clay minerals; Interactions between manganese oxides and multiple ringed aromatic compounds; Mobility and persistence of metolachlor and terbuthylazine in field lysimeters; Soil-pesticide interactions and their impact on the volatilization process; Factors affecting the movements, reactions, and biotransformations ox xenobiotics; Effect of soil minerals on the microbial formation of enzymes and their possible use in remediation of chemically polluted sites; Position paper of part II; Effect of microorganisms on mobility of heavy metals in soils; Interactions of copper with soil humic substances; Adsorption of phosphate on variable charge minerals: competitive effect of organic ligands; Cadmium adsorption on the hydroxyaluminum-montmorillonite complex as influencend by oxalate; Influence of citrate on selenite sorption-desorption on short-range ordered aluminum hydroxides; Role of amorphous fe oxides in controlling retention of heavy metal elements in soils; Effect of natural organic matter and pH on the bioavailability of metal ions in soils; Seasonal changes of organic matter, pH, nitrogen and some metals in forest topsoils in Austria: a case study of two soils with and whithout a litter layer; Substituion of rock phosphate and legumes for commercial fertilizers; Effect of single and combined inoculation with azotobacter and VA mycorrhizal fungi on growth and mineral nutrient contents of maize and wheat plants; Position paper of part I; Interactions of clays with microorganisms and bacterial survival in soil: a physicochemical perspective; Enumeration, survival, and beneficial activities of microorganisms introduced into soil; Effects of clay minerals, oxyhydroxides, and humic matter on microbial communities of soil, sediment, and water; Activity, stability, and kinetc properties of enzymes immobilized on clay minerals and organomineral complexes; Influence of site conditions and heavy metals on enzyme activities of forest topsoils; Aluminum toxicity: a major stress for microbes in the environment; Biological response to contamination with pentachlorophenol and mercuric chloride in a high organic matter soil; Ecology of 2,4-D degradation in three palouse silt loam soils.

The fourth edition of Soil Microbiology, Ecology and Biochemistry updates this widely used reference as the study and understanding of soil biota, their function, and the dynamics of soil organic matter has been revolutionized by molecular and instrumental techniques, and information technology. Knowledge of soil microbiology, ecology and biochemistry is central to our understanding of organisms and their processes and interactions with their environment. In a time of great global change and increased emphasis on biodiversity and food security, soil microbiology and ecology has become an increasingly important topic. Revised by a group of world-renowned authors in many institutions and disciplines, this work relates the breakthroughs in knowledge in this important field to its history as well as future applications. The new edition provides readable, practical, impactful information for its many applied and fundamental disciplines. Professionals turn to this text as a reference for fundamental knowledge in their field or to inform management practices. New section on "Methods in Studying Soil Organic Matter Formation and Nutrient Dynamics" to balance the two successful chapters on microbial and physiological methodology Includes expanded information on soil interactions with organisms involved in human and plant disease Improved readability and integration for an ever-widening audience in his field Integrated concepts related to soil biota, diversity, and function allow readers in multiple disciplines to understand the complex soil biota and their function

How can we understand and rise to the environmental challenges of global change? One clear answer is to understand the science of global change, not solely in terms of the processes that control changes in climate and the composition of the atmosphere, but in how ecosystems and human society interact with these changes. In the last two decades of the twentieth century, a number of such research effortsâ€"supported by computer and satellite technologyâ€"have been launched. Yet many opportunities for integration remain unexploited, and many fundamental questions remain about the earth's capacity to support a growing human population. This volume encourages a renewed commitment to understanding global change and sets a direction for research in the decade ahead. Through case studies the book explores what can be learned from the lessons of the past 20 years and what are the outstanding scientific questions. Highlights include: Research imperatives and strategies for investigators in the areas of atmospheric chemistry, climate, ecosystem studies, and human dimensions of global change. The context of climate change, including lessons to be gleaned from paleoclimatology. Human responses toâ€"and forcing ofâ€"projected global change. This book offers a comprehensive overview of global change research to date and provides a framework for answering urgent questions.

The available literature on freshwater fungi is limited. Over the subsequent years a considerable volume of scientific papers have appeared scattered throughout numerous journals. There is therefore no recent synthesis of the subject and this is the objective of the proposed book. Freshwater habitats are rich in fungi with some 3,000 described species, most of papers focussing on their identification, substrata they grow on and world distribution. However, these fungi play an important role in the freshwater ecosystem, and are primarily involved in the breakdown of leaf litter contributing food for detritus feeders. Our book will bring together a wide range of acclaimed mycologists to review recent developments on the biology and ecology of freshwater fungi, particularly their molecular phylogeny, biodiversity, causative diseases of freshwater amphibians, fishes and invertebrate animals, decomposition of leaf litter, stream pollution and their potential role in bioremediation.

Arctic environments are subject to acute nitrogen deposition events, in which 40% or more of annual atmospheric N input can be deposited as acidic rainfall in less than one week. The overall aim of this research was to investigate the impact of acute N deposition events upon soil microbial communities in High Arctic tundra. A plot scale field experiment, established on the High Arctic tundra (Ny-Ålesund, Svalbard), and a microcosm experiment, were used to simulate acute N deposition over the summer by the application of NH4NO3 solution at ~pH 4, at rates of 0.4, 4 and 12 kg N ha-1 yr-1. Changes in soil characteristics were measured on soil samples from the organic and mineral horizons. Variation in the structure and abundance of bacterial, archaeal, and fungal communities and in the presence and abundance of N-cycling functional guilds were investigated using molecular (DNA)-based approaches such as Terminal Restriction Fragment Polymorphism (T-RFLP) and quantitative-PCR. T-RFLP analysis revealed significant (P

Authored by world-class scientists and scholars, The Handbook of Natural Resources, Second Edition, is an excellent reference for understanding the consequences of changing natural resources to the degradation of ecological integrity and the sustainability of life. Based on the content of the bestselling and CHOICE-awarded Encyclopedia of Natural Resources, this new edition demonstrates the major challenges that the society is facing for the sustainability of all well-being on the planet Earth. The experience, evidence, methods, and models used in studying natural resources are presented in six stand-alone volumes, arranged along the main systems of land, water, and air. It reviews state-of-the-art knowledge, highlights advances made in different areas, and provides guidance for the appropriate use of remote sensing and geospatial data with field-based measurements in the study of natural resources. Volume 1, Terrestrial Ecosystems and Biodiversity, provides fundamental information on terrestrial ecosystems, approaches to monitoring, and impacts of climate change on natural vegetation and forests. New to this edition are discussions on biodiversity conservation, gross and net primary production, soil microbiology, land surface phenology, and decision support systems. This volume demonstrates the key processes, methods, and models used through many case studies from around the world. Written in an easy-to-reference manner, The Handbook of Natural Resources, Second Edition, as individual volumes or as a complete set, is an essential reading for anyone looking for a deeper understanding of the science and management of natural resources. Public and private libraries, educational and research institutions, scientists, scholars, and resource managers will benefit enormously from this set. Individual volumes and chapters can also be used in a wide variety of both graduate and undergraduate courses in environmental science and natural science at different levels and disciplines, such as biology, geography, earth system science, and ecology.

The ocean has absorbed a significant portion of all human-made carbon dioxide emissions. This benefits human society by moderating the rate of climate change, but also causes unprecedented changes to ocean chemistry. Carbon dioxide taken up by the ocean decreases the pH of the water and leads to a suite of chemical changes collectively known as ocean acidification. The long term consequences of ocean acidification are not known, but are expected to result in changes to many ecosystems and the services they provide to society. Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean reviews the current state of knowledge, explores gaps in understanding, and identifies several key findings. Like climate change, ocean acidification is a growing global problem that will intensify with continued CO2 emissions and has the potential to change marine ecosystems and affect benefits to society. The federal government has taken positive initial steps by developing a national ocean acidification program, but more information is needed to fully understand and address the threat that ocean acidification may pose to marine ecosystems and the services they provide. In addition, a global observation network of chemical and biological sensors is needed to monitor changes in ocean conditions attributable to acidification.

The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for assessing the science related to climate change. It provides policymakers with regular assessments of the scientific basis of human-induced climate change, its impacts and future risks, and options for adaptation and mitigation. This IPCC Special Report on the Ocean and Cryosphere in a Changing Climate is the most comprehensive and up-to-date assessment of the observed and projected changes to the ocean and cryosphere and their associated impacts and risks, with a focus on resilience, risk management response options, and adaptation measures, considering both their potential and limitations. It brings together knowledge on physical and biogeochemical changes, the interplay with ecosystem changes, and the implications for human communities. It serves policymakers, decision makers, stakeholders, and all interested parties with unbiased, up-to-date, policy-relevant information. This title is also available as Open Access on Cambridge Core.