Role Of Microbial Communities In Mediating An Ecosystems Response To Global Change

A central goal of global change biology is to predict the impact of environmental change on ecosystem processes. Currently, most global change models treat the local microbial community as a single, homogenously functioning entity, thereby assuming that the specific microbial composition is functionally irrelevant. However, microorganisms perform key transformations in ecosystems, and recent research demonstrates that microbial communities vary greatly across space and in response to environmental change. Therefore, parameters describing microbial communities may be key for improving predictions of how future global changes will impact ecosystem processes. For this reason, my dissertation research examined the effect of environmental changes on resident communities and determined how potential shifts in microbial community composition will impact litter decomposition rates. To accomplish this, I gathered litter samples from a chaparral ecosystem undergoing global change manipulations (elevated nitrogen availability or reduced precipitation), and characterized the microbial community using 454 high-throughput sequencing (Chapter 1). While microbial communities are much more variable through time, this research showed that microbial composition will likely shift in response to environmental change. I also examined the role of microbial community composition for a key ecosystem process, litter decomposition, and how that role changes under environmental perturbations. By isolating microbial taxa from the same ecosystem discussed above, I constructed artificial microbial communities with varying composition. I then conducted a laboratory experiment in which I subjected the communities to different global change manipulations and monitored decomposition rates and community composition (Chapter 2). Microbial composition had a main effect on leaf litter decomposition and also interacted with the environmental treatment, suggesting that future shifts in microbial communities will influence the magnitude in which environmental change affects ecosystem processes. Lastly, I investigated the functional and response traits of individual microbial taxa to better predict how microbial communities might respond to global change perturbations, and found that many functional traits displayed a phylogenetic pattern, but a taxa's response to increased temperature did not (Chapter 3). Ultimately, this set of studies further justifies the need to incorporate microbial communities into models and begins to identify which parameters might be most relevant.

Advances in next generation sequencing technologies, omics, and bioinformatics are revealing a tremendous and unsuspected diversity of microbes, both at a compositional and functional level. Moreover, the expansion of ecological concepts into microbial ecology has greatly advanced our comprehension of the role microbes play in the functioning of ecosystems across a wide range of biomes. Super-imposed on this new information about microbes, their functions and how they are organized, environmental gradients are changing rapidly, largely driven by direct and indirect human activities. In the context of global change, understanding the mechanisms that shape microbial communities is pivotal to predict microbial responses to novel selective forces and their implications at the local as well as global scale. One of the main features of microbial communities is their ability to react to changes in the environment. Thus, many studies have reported changes in the performance and composition of communities along environmental gradients. However, the mechanisms underlying these responses remain unclear. It is assumed that the response of microbes to changes in the environment is mediated by a complex combination of shifts in the physiological properties, single-cell activities, or composition of communities: it may occur by means of physiological adjustments of the taxa present in a community or selecting towards more tolerant/better adapted phylotypes. Knowing whether certain factors trigger one, many, or all mechanisms would greatly increase confidence in predictions of future microbial composition and processes. This Research Topic brings together studies that applied the latest molecular techniques for studying microbial composition and functioning and integrated ecological, biogeochemical and/or modeling approaches to provide a comprehensive and mechanistic perspective of the responses of micro-organisms to environmental changes. This Research Topic presents new findings on environmental parameters influencing microbial communities, the type and magnitude of response and differences in the response among microbial groups, and which collectively deepen our current understanding and knowledge of the underlying mechanisms of microbial structural and functional responses to environmental changes and gradients in both aquatic and terrestrial ecosystems. The body of work has, furthermore, identified many challenges and questions that yet remain to be addressed and new perspectives to follow up on.

The cryosphere stands for environments where water appears in a frozen form. It includes permafrost, glaciers, ice sheets, and sea ice and is currently more affected by Global Change than most other regions of the Earth. In the cryosphere, limited water availability and subzero temperatures cause extreme conditions for all kind of life which microorganisms can cope with extremely well. The cryosphere’s microbiota displays an unexpectedly large genetic potential, and taxonomic as well as functional diversity which, however, we still only begin to map. Also, microbial communities influence reaction patterns of the cryosphere towards Global Change. Altered patterns of seasonal temperature fluctuations and precipitation are expected in the Arctic and will affect the microbial turnover of soil organic matter (SOM). Activation of nutrients by thawing and increased active layer thickness as well as erosion renders nutrient stocks accessible to microbial activities. Also, glacier melt and retreat stimulate microbial life in turn influencing albedo and surface temperatures. In this context, the functional resilience of microbial communities in the cryosphere is of major interest. Particularly important is the ability of microorganisms and microbial communities to respond to changes in their surroundings by intracellular regulation and population shifts within functional niches, respectively. Research on microbial life exposed to permanent freeze or seasonal freeze-thaw cycles has led to astonishing findings about microbial versatility, adaptation, and diversity. Microorganisms thrive in cold habitats and new sequencing techniques have produced large amounts of genomic, metagenomic, and metatranscriptomic data that allow insights into the fascinating microbial ecology and physiology at low and subzero temperatures. Moreover, some of the frozen ecosystems such as permafrost constitute major global carbon and nitrogen storages, but can also act as sources of the greenhouse gases methane and nitrous oxide. In this book we summarize state of the art knowledge on whether environmental changes are met by a flexible microbial community retaining its function, or if the altered conditions also render the community in a state of altered properties that affect the Earth’s element cycles and climate. This book brings together research on the cryosphere’s microbiota including permafrost, glaciers, and sea ice in Arctic and Antarctic regions. Different spatial scales and levels of complexity are considered, spanning from ecosystem level to pure culture studies of model microbes in the laboratory. It aims to attract a wide range of parties with interest in the effect of climate change and/or low temperatures on microbial nutrient cycling and physiology.

This book provides an enlightening picture of the role of microbes for sustaining life systems and how climatic factors will change the course of the processes. Climate Change and Microbes: Impacts and Vulnerability explores the little-addressed issue of the effects of climate change on microbial ecosystems and the influence of climate change on microbiome diversity across various habitats and regions. Recent years have seen the evidence that microbial communities are neither immune to disruption nor do they have the capacity to recover completely after a stressful climate event. This volume documents the important role of microorganisms as climate engineers and considers mitigation and adaptation strategies as well. It goes on to present the research that addresses a diverse array of topics on the impact of climate change on plant-microbe interactions and microbial aquatic life and change-induced aggravations in microbial populations and processes. The book also addresses microbial foodborne diseases resulting from challenging climates. Other topics include algae as indicators of climate change and strategies for facilitating sustainable agro-ecosystems. This book will be immensely helpful in the study of plant microbiology, agricultural sciences, biotechnology, climate science, and environmental microbiology. It will also be applicable to the field of microbial biotechnology, agricultural, and other life and environmental sciences.

Tropical ecosystems are different in important ways from those of temperate regions. They are a major reservoir of plant and animal biodiversity and play important roles in global climate regulation and biogeochemical cycling. They are also under great threat due to the conversion of tropical ecosystems to other uses. Thus, in the context of global change, it is crucial to understand how environmental factors, biogeographic patterns, and land use changes interact to influence the structure and function of microbial communities in these ecosystems. The contributions to this Research Topic showcase the current knowledge regarding microbial ecology in tropical ecosystems, identify many challenges and questions that remain to be addressed and open up new horizons in our understanding of the environmental and anthropological factors controlling microbial communities in these important ecosystems.

The distribution and function of microorganisms are of crucial importance for the flow of matter in the Earth's biogeochemical cycles. Effects of microbial communities on the carbon and nitrogen cycles are particularly important for producing climate gases such as CO2, CH4, or N2O. However, the biogeochemical cycles are reversely impacted by global climate change, for example by increasing temperature, increasing CO2 concentration, or changing soil humidity. However microbes may respond differently, by accelerating or by alleviating, human-caused climate change. Understanding of microbial ecology in the different ecosystems on Earth, such as soil, oceans, or inland waters, is essential for our ability to assess the importance of biogeochemical cycles-climate feedbacks. Unfortunately, microbial communities are extremely complex in structure and function and can be affected by climate and other global changes in many ways, which impedes our ability to draw reliable conclusions. In this book, a broad range of renowned scientists reviews the most important hot-topics in the area of climate change and microbial ecology, thus providing a timely and authoritative overview of this increasingly important area. Individual chapters cover the various ecosystems on Earth as well as the different groups of microorganisms with respect to different cycles of matter. In addition, special chapters cover applied aspects, such as land-use and geoengineering. This is an essential book for every microbial ecologist from the PhD student to the experienced scientist and is also recommended for everyone interested in the field of global climate change. [Subject: Microbiology, Climate Change, Microbial Ecology]

Microbes in Land Use Change Management details the various roles of microbial resources in management of land uses and how the microbes can be used for the source of income due to their cultivation for the purpose of biomass and bioenergy production. Using various techniques, the disturbed and marginal lands may also be restored eco-friendly in present era to fulfil the feeding needs of mankind around the globe. Microbes in Land Use Change Management provides standard and up to date information towards the land use change management using various microbial technologies to enhance the productivity of agriculture. Needless to say that Microbes in Land Use Change Management also considers the areas including generation of alternative energy sources, restoration of degraded and marginal lands, mitigation of global warming gases and next generation -omics technique etc. Land use change affects environment conditions and soil microbial community. Microbial population and its species diversity have influence in maintaining ecosystem balance. The study of changes of microbial population provides an idea about the variation occurring in a specific area and possibilities of restoration. Meant for a multidisciplinary audience Microbes in Land Use Change Management shows the need of next-generation omics technologies to explore microbial diversity. Describes the role of microbes in generation of alternative source of energy Gives recent information related to various microbial technology and their diversified applications Provides thorough insight in the problems related to landscape dynamics, restoration of soil, reclamation of lands mitigation of global warming gases etc. eco-friendly way using versatility of microbes Includes microbial tools and technology in reclamation of degraded, disturbed and marginal lands, mitigation of global warming gases

Beginning with the germ theory of disease in the 19th century and extending through most of the 20th century, microbes were believed to live their lives as solitary, unicellular, disease-causing organisms . This perception stemmed from the focus of most investigators on organisms that could be grown in the laboratory as cellular monocultures, often dispersed in liquid, and under ambient conditions of temperature, lighting, and humidity. Most such inquiries were designed to identify microbial pathogens by satisfying Koch's postulates.3 This pathogen-centric approach to the study of microorganisms produced a metaphorical "war" against these microbial invaders waged with antibiotic therapies, while simultaneously obscuring the dynamic relationships that exist among and between host organisms and their associated microorganisms-only a tiny fraction of which act as pathogens. Despite their obvious importance, very little is actually known about the processes and factors that influence the assembly, function, and stability of microbial communities. Gaining this knowledge will require a seismic shift away from the study of individual microbes in isolation to inquiries into the nature of diverse and often complex microbial communities, the forces that shape them, and their relationships with other communities and organisms, including their multicellular hosts. On March 6 and 7, 2012, the Institute of Medicine's (IOM's) Forum on Microbial Threats hosted a public workshop to explore the emerging science of the "social biology" of microbial communities. Workshop presentations and discussions embraced a wide spectrum of topics, experimental systems, and theoretical perspectives representative of the current, multifaceted exploration of the microbial frontier. Participants discussed ecological, evolutionary, and genetic factors contributing to the assembly, function, and stability of microbial communities; how microbial communities adapt and respond to environmental stimuli; theoretical and experimental approaches to advance this nascent field; and potential applications of knowledge gained from the study of microbial communities for the improvement of human, animal, plant, and ecosystem health and toward a deeper understanding of microbial diversity and evolution. The Social Biology of Microbial Communities: Workshop Summary further explains the happenings of the workshop.