A Practicum Project Researching the Microbial Community in Sediment Cores and the Current Chemical Parameters of Lake Qinghai, China PDF Download
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Author: Nicole Kay Berzins
Publisher:
ISBN:
Category : Biotic communities
Languages : en
Pages : 23
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Book Description
Saline lakes at high altitudes represent an important and extreme microbial ecosystem, yet little is known about microbial diversity in such environments. The objective of this study was to examine the change of microbial diversity from the bottom of the lake to sediments from Qinghai Lake and the two sister lakes, Erhai and Garhi Lake in China. The lakes are saline and alkaline and are located on the Qinghai-Tibetan Plateau at an altitude of 3196 m above sea level. An interdisciplinary approach was taken in this long term study and specifically this report provides in depth laboratory cultivation and enrichment procedures along with field results. This data was used to assess microbial communities in the lake ecosystems and better understand the bacterial responses to climatic and environmental changes of Qinghai Lake.
Author: Nicole Kay Berzins
Publisher:
ISBN:
Category : Biotic communities
Languages : en
Pages : 23
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Book Description
Saline lakes at high altitudes represent an important and extreme microbial ecosystem, yet little is known about microbial diversity in such environments. The objective of this study was to examine the change of microbial diversity from the bottom of the lake to sediments from Qinghai Lake and the two sister lakes, Erhai and Garhi Lake in China. The lakes are saline and alkaline and are located on the Qinghai-Tibetan Plateau at an altitude of 3196 m above sea level. An interdisciplinary approach was taken in this long term study and specifically this report provides in depth laboratory cultivation and enrichment procedures along with field results. This data was used to assess microbial communities in the lake ecosystems and better understand the bacterial responses to climatic and environmental changes of Qinghai Lake.
Author: Lunhui Lu
Publisher: Frontiers Media SA
ISBN: 2832539874
Category : Science
Languages : en
Pages : 188
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Book Description
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.
Author: Hongchen Jiang
Publisher:
ISBN:
Category : Geomicrobiology
Languages : en
Pages : 206
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Book Description
Lakes constitute an important part of the global ecosystem as habitats in these environments play an important role in biogeochemical cycles of life-essential elements. The cycles of carbon, nitrogen and sulfur in these ecosystems are intimately linked to global phenomena such as climate change. Microorganisms are at the base of the food chain in these environments and drive the cycling of carbon and nitrogen in water columns and the sediments. Despite many studies on microbial ecology of lake ecosystems, significant gaps exist in our knowledge of how microbial and geological processes interact with each other. In this dissertation, I have studied the ecology and biogeochemistry of lakes on the Tibetan Plateau, NW China. The Tibetan lakes are pristine and stable with multiple environmental gradients (among which are salinity, pH, and ammonia concentration). These characteristics allow an assessment of mutual interactions of microorganisms and geochemical conditions in these lakes. Two lakes were chosen for this project: Lake Chaka and Qinghai Lake. These two lakes have contrasting salinity and pH: slightly saline (12 g/L) and alkaline (9.3) for Qinghai Lake and hypersaline (325 g/L) but neutral pH (7.4) for Chaka Lake. We have taken an integrated approach combining geochemistry, molecular phylogeny (both DNA and RNA based, both 16S rRNA and amoA gene), quantitative PCR (total Bacteria, Archaea, total crenarchaeota, AOA, and AOB), and cultivation and isolation. Both lake water and sediments have been analyzed. The results are divided into four chapters and they are summarized below. In addition, I also studied microbial communities and functions in sediments from South China Sea, a potential site for gas hydrate deposits. This work was done as extra add-on to the microbial ecology studies in Titeban lakes.
Author: Sally Graham Hornor
Publisher:
ISBN:
Category : Pond ecology
Languages : en
Pages : 172
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Book Description
Author: Marit Rianne van Erk
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Microbial mineralization in intertidal sandy sediments plays an essential role in coastal carbon cycling. Surface sediments in these dynamic systems frequently switch between oxic and anoxic conditions depending on factors such as tides and waves. Additionally, they are occasionally subjected to the sudden, high deposition of organic material. When the production rate of the reduced products of anaerobic degradation is higher than the transport rate of oxygen into the sediments, reduced intermediates can accumulate and eventually be exported from the sediments. The aim of this study was to improve the understanding of the response of microbial activity to dynamics in electron donor and acceptor availability, particularly of anaerobic microbial degradation of the organic material. In Chapter 2, a sandy beach on the island of Helgoland was explored, which regularly receives large depositions of kelp debris. A combination of in situ and laboratory microsensing, 35S radiotracer incubations, porewater and sediment analyses, and molecular analyses was used to address the impact of kelp deposition on microbial mineralization and community composition in underlying sandy sediments. The sedimentary biogeochemical conditions on the beach were distinct, with high concentrations of nutrients, dissolved organic and inorganic carbon, and a low pH. Kelp deposition shaped the microbial community, which is optimized for the use of kelp material. The community could immediately degrade kelp upon deposition, which fostered high production rates of reduced products. As these rates were higher than the transport rate of oxygen into the sediments, sulfide accumulated and was exported from the sediments. The export of sulfide to the sea led to the development of a diverse community of filamentous sulfide-oxidizing bacteria. As Chapter 2 highlighted that the microbial community in sediments associated with kelp deposits must be highly specialized to be able to deal with the complex organic material in kelp, Chapter 3 aimed to illuminate the adaptation of microbial communities in these sediments to the degradation of kelp-derived carbohydrate substrates. Oxygen microsensor and 35S radiotracer methods showed strong increases in aerobic respiration and sulfate reduction rates after the addition of specific carbohydrates. The community was indeed specialized to the degradation of kelp-derived carbohydrates. Remarkably, kelp-derived polysaccharides often led to higher aerobic respiration rates than monomers. Monosaccharide analysis and microarray analysis were used to determine the substrate pools in sediments. Respiration rates were up two orders of magnitude higher than in reference sediments, though substrate pools were approximately equal. Thus, substrate turnover rates are much higher on beaches with regular kelp deposition, where microbial communities are more active and are specialized in the carbohydrates they often encounter. Chapter 4 focused on illuminating the effect of transient oxygen exposure on the efficiency of microbial mineralization in an intertidal sandflat in the Wadden Sea. This included testing the hypothesis that reactive oxygen species (ROS) are present in high concentrations in intertidal permeable sediments and control microbial mineralization rates. We incubated sediment slurries that transitioned from oxic to anoxic conditions and slurries that were anoxic throughout the incubation period. Furthermore, we measured hydrogen peroxide concentrations in porewater. Sulfate-reducing bacteria in intertidal permeable sediments are frequently exposed to oxygen. Yet, this did not select for sulfate-reducing bacteria that perform sulfate reduction in the presence of oxygen. Whereas oxygen inhibited sulfate reduction, the sulfate-reducing bacteria were not eliminated by oxygen, but sulfate reduction instantly resumed after oxygen was depleted. The presence of oxygen even boosted subsequent sulfate reduction in the anoxic period. This could be related to oxygen-stimulated hydrolysis of macromolecules during the oxic period. High levels of ROS were found in the porewater of the intertidal flat. ROS are detrimental for microorganisms, as they are able to degrade cellular components and thus lead to cell death. Indeed, removal of ROS in slurry incubations led to strongly increased microbial mineralization rates. This study highlights the contradictory effects of redox shifts on mineralization efficiency, with the presence of oxygen increasing efficiency of subsequent anaerobic processes, even though ROS appeared to inhibit mineralization. In Chapter 5, a sulfide-oxidizing community forming egg-shaped sulfur structures on top of a hot smoker in the deep-sea was studied. Hydrodynamics around such structures are dominated by diffusion, contrary to the advection-dominated system of Chapter 2. Both studied systems are characterized by input of reduced material in an oxic ecosystem, and are therefore out of thermodynamic equilibrium. Comparison between the systems described in Chapter 2 and Chapter 5 aimed to further illuminate the oxidative side of the sulfur cycle in the two contrasting energy-rich redox-variable systems. Different environmental conditions, including hydrodynamics, select for specific sulfide-oxidizing communities and morphologies. The mixing of sulfide into turbulent oxygenated seawater led to the development of filamentous mats of sulfide-oxidizing bacteria growing on rocks at the low tide waterline of the beach (Chapter 2). This attachment prevents the sulfide-oxidizing bacteria from being washed away, and the filamentous structure allows them to make optimal use of the dynamic conditions of the turbulent seawater. On the other hand, the egg-shaped gelatinous sulfur structure produced by sulfide-oxidizing bacteria (Chapter 5) might result from the narrow overlap of oxygen and sulfide which are provided from the same direction. Overall, this study shows that changes in the availability of electron donors and acceptors, and thus redox dynamics, have a large effect on microbial activity. Large influxes of organic material result in a system that is out of thermodynamic equilibrium, and exports reduced compounds towards the sea. Microbial communities are optimized for these conditions, and can directly access the available organic material, while also being able to make use of the reduced compounds that result from microbial mineralization. Sulfide-oxidizing bacteria at the low tide waterline are adapted to the especially dynamic conditions of this environment. While the production of ROS reduces microbial mineralization, the presence of oxygen should not only be seen as an inhibitor of anaerobic microbial mineralization, but also as crucial to the production of electron donors available at the start of anoxia. This study therefore highlights the importance of spatio-temporal dynamics in electron donor and acceptor availability for microbial activity.
Author: Aaron M. Ellison
Publisher: MDPI
ISBN: 3039213091
Category : Science
Languages : en
Pages : 274
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Book Description
This book is a printed edition of the Special Issue Causes and Consequences of Species Diversity in Forest Ecosystems that was published in Forests
Author: Dietrich Werner
Publisher: Springer Science & Business Media
ISBN: 9781402035425
Category : Technology & Engineering
Languages : en
Pages : 380
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Book Description
Sustainability has a major part to play in the global challenge of continued development of regions, countries, and continents all around the World and biological nitrogen fixation has a key role in this process. This volume begins with chapters specifically addressing crops of major global importance, such as soybeans, rice, and sugar cane. It continues with a second important focus, agroforestry, and describes the use and promise of both legume trees with their rhizobial symbionts and other nitrogen-fixing trees with their actinorhizal colonization. An over-arching theme of all chapters is the interaction of the plants and trees with microbes and this theme allows other aspects of soil microbiology, such as interactions with arbuscular mycorrhizal fungi and the impact of soil-stress factors on biological nitrogen fixation, to be addressed. Furthermore, a link to basic science occurs through the inclusion of chapters describing the biogeochemically important nitrogen cycle and its key relationships among nitrogen fixation, nitrification, and denitrification. The volume then provides an up-to-date view of the production of microbial inocula, especially those for legume crops.
Author: Beth A. Middleton
Publisher: John Wiley & Sons
ISBN: 0471423238
Category : Technology & Engineering
Languages : en
Pages : 322
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Book Description
The latest cutting-edge research on flood pulsing and wetland restoration in North America Presenting the latest research from leaders in the field of restoration ecology, Flood Pulsing in Wetlands reflects the current movement to incorporate flood pulsing into wetland restoration efforts. Emphasizing how integral flood pulsing is to successful wetland restoration, the book's contributors provide descriptions of restoration projects across North America in which flood pulsing has been primarily used to restore beneficial hydrodynamic conditions to floodplain areas, and improve or save vegetation, wildlife, and terrain. Detailing the importance and applicability of recreating flood-pulsed conditions on floodplains for successful restoration, the first chapter introduces the concept of flood pulse and its unique role in wetland restoration. The following chapters detail the strategies and results of individual projects and the impact flood pulsing had on the projects' overall goals. Case studies detail the history of each region, such as the Southwest, including the Sonoran Desert communities and the Middle Rio Grande; the Missouri River in Montana; the Illinois River Valley; and the Southeast, including Brushy Lake, Arkansas. Also documented is the most famous case of flood pulsing used in the restoration of an entire landscape, the Kissimmee River project. Approaches used to restore specific plant and animal populations, the unique ecological concerns of each region, and the future outlook for each area are fully described. Extensive bibliographies for each chapter make Flood Pulsing in Wetlands: Restoring the Natural Hydrological Balance the essential reference for restoration ecologists, consultants in wetland restoration, government and restoration agency employees, land managers, ecologists, foresters, and geologists.
Author: Maxwell Boykoff
Publisher: Cambridge University Press
ISBN: 1107195381
Category : Business & Economics
Languages : en
Pages : 321
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Book Description
Through this assessment of creative (climate) communications, readers will understand what works where, when, why and under what conditions.
Author: Radu Popa
Publisher: Springer Science & Business Media
ISBN: 9783540204909
Category : Science
Languages : en
Pages : 280
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Book Description
Systematically explores the early origins and basic definition of life. Investigates the major theories of the origins of life in light of modern research with the aim of distinguishing between the necessary and the optional and between deterministic and random influences in the emergence of what we call ‘life.’ Treats and views life as a cosmic phenomenon whose emergence and driving force should be viewed independently from its Earth-bound natural history. Synthesizes all the fundamental life-related developments in a comprehensive scenario, and makes the argument that understanding life in its broadest context requires a material-independent perspective that identifies its essential fingerprints
