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Book Eco evolutionary Modeling of Soil Microbial Decomposition in a Warming Climate

Download or read book Eco evolutionary Modeling of Soil Microbial Decomposition in a Warming Climate written by Elsa Abs and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: One major source of uncertainty in global climate predictions is the extent to which global warming will increase atmospheric CO2 concentrations through enhanced microbial decomposition of soil organic matter. There is therefore a critical need for models that mechanistically link decomposition to the dynamics of microbial communities, and integration of these mechanistic models in global projection models of the Earth system. Mathematical models of soil microbial decomposition models have recently been introduced to predict soil C stocks and heterotrophic soil respiration, especially in the context of climate change. Thus far, models focused on physiological and ecological mechanisms of microbial responses, leaving the role of evolutionary adaptation poorly understood. My thesis addresses this gap and evaluates the hypothesis that microbial evolutionary adaptation to warming can have a significant impact on the global carbon cycle. After reviewing mechanistic, non- evolutionary microbial models of decomposition, I construct an eco-evolutionary spatially explicit, stochastic model, scaling up from microscopic processes acting at the level of cells and extracellular molecules. I use an approximated version of the model (spatially implicit, deterministic) to investigate the eco-evolutionary response of a soil microbe-enzyme system to warming, under three possible scenarios for the influence of temperature on microbial activity. In the absence of microbial evolution, warming results in soil carbon loss to the atmosphere (an amplification of climate change) in all scenarios. Microbial evolutionary adaptation generally aggravates soil carbon loss in cold ecosystems, and may aggravate, buffer or even reverse carbon loss in warm ecosystems. Constraining the model with observations from five contrasting biomes reveals evolutionary aggravation of soil carbon loss to be the most likely outcome. Earth-scale projections of carbon stocks that integrate my eco-evolutionary model support the prediction of a significant global aggravation of soil C loss due to microbial evolution. Dormant soils, in which microbial activity is very low, play a special role in the long-term eco-evolutionary dynamics of global soil carbon, since in these regions, the negative effect of evolution on soil carbon stocks may not kick in until the microbial community shifts from dormant to active, and may thus be delayed by decades. Overall, my work is a first step toward predictive modeling of eco- evolutionary dynamics of carbon cycling; it also lays the ground for a broad future research program that will empirically test model predictions about the role of evolutionary mechanisms in different systems across the globe, by leveraging the growing global archive of soil metagenomics data to quantify variations in microbial metabolic functions and their response to selection. Mots clés en français (10 max) : changement climatique, cycle du carbone, décomposition, projections globales, évolution microbienne, dynamiques adaptatives, rétroaction sol-climat, évolution de la coopération, modèles individu-centrés.Mots clés en anglais : climate change, carbon cycle, decomposition, global predictions, microbial evolution, adaptive dynamics, soil-climate feedbacks, evolution of cooperation, individual-based models.

Book Ecosystem Consequences of Soil Warming

Download or read book Ecosystem Consequences of Soil Warming written by Jacqueline E. Mohan and published by Academic Press. This book was released on 2019-04-12 with total page 594 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ecosystem Consequences of Soil Warming: Microbes, Vegetation, Fauna and Soil Biogeochemistry focuses on biotic and biogeochemical responses to warmer soils including plant and microbial evolution. It covers various field settings, such as arctic tundra; alpine meadows; temperate, tropical and subalpine forests; drylands; and grassland ecosystems. Information integrates multiple natural science disciplines, providing a holistic, integrative approach that will help readers understand and forecast future planetwide responses to soil warming. Students and educators will find this book informative for understanding biotic and biogeochemical responses to changing climatic conditions. Scientists from a wide range of disciplines, including soil scientists, ecologists, geneticists, as well as molecular, evolutionary and conservation biologists, will find this book a valuable resource in understanding and planning for warmer climate conditions. - Emphasizes biological components of soils, plants and microbes that provide linkages to physics and chemistry - Brings together chapters written by global scientific experts with interests in communication and education - Includes coverage of polar, alpine, tropical, temperate and dryland ecosystems

Book Biogeochemical Cycles

    Book Details:
  • Author : Katerina Dontsova
  • Publisher : John Wiley & Sons
  • Release : 2020-04-14
  • ISBN : 1119413303
  • Pages : 336 pages

Download or read book Biogeochemical Cycles written by Katerina Dontsova and published by John Wiley & Sons. This book was released on 2020-04-14 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Elements move through Earth's critical zone along interconnected pathways that are strongly influenced by fluctuations in water and energy. The biogeochemical cycling of elements is inextricably linked to changes in climate and ecological disturbances, both natural and man-made. Biogeochemical Cycles: Ecological Drivers and Environmental Impact examines the influences and effects of biogeochemical elemental cycles in different ecosystems in the critical zone. Volume highlights include: Impact of global change on the biogeochemical functioning of diverse ecosystems Biological drivers of soil, rock, and mineral weathering Natural elemental sources for improving sustainability of ecosystems Links between natural ecosystems and managed agricultural systems Non-carbon elemental cycles affected by climate change Subsystems particularly vulnerable to global change The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals. Book Review: http://www.elementsmagazine.org/archives/e16_6/e16_6_dep_bookreview.pdf

Book Ecological Mechanisms Underlying Soil Microbial Responses to Climate Change

Download or read book Ecological Mechanisms Underlying Soil Microbial Responses to Climate Change written by Bonnie Grace Waring and published by . This book was released on 2013 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil microbes influence the global carbon cycle via their role in the decomposition and formation of soil organic matter. Thus, rates of ecosystem processes such as primary production, soil respiration, and pedogenesis are sensitive to changes in the aggregate functional traits of the entire microbial community. To predict the magnitude and direction of microbial feedbacks on climate change, it is necessary to identify the physiological, ecological, and evolutionary mechanisms that underlie microbes' responses to altered temperature and rainfall. Therefore, I examined microbial community composition and function in relation to manipulations of resource availability and precipitation in two contrasting ecosystems: a tropical rainforest at La Selva Biological Station, Costa Rica, and a semi-arid grassland in central Texas. I conducted a leaf litter decomposition experiment at La Selva to identify the physiological constraints on microbial allocation to extracellular enzymes, which degrade organic matter. I found strong evidence that microbial enzyme production is decoupled from foliar stoichiometry, consistent with weak links between leaf litter nutrients and decomposition rates at the pan-tropical scale. Next, to examine whether ecological trade-offs within microbial communities may drive shifts in carbon cycling at local spatial scales, I quantified changes in soil fungal and bacterial community composition in response to an in situ precipitation exclusion experiment I established at La Selva. Although drought-induced shifts in community structure were small, large increases in biomass-specific respiration rates were observed under dry conditions. These findings suggest that physiological adjustments to drought may constitute an important feedback on climate change in wet tropical forests. Finally, I focused on microbial community responses to climate change within a meta-community framework, using a reciprocal transplant experiment to investigate how dispersal shapes bacterial community structure along a natural rainfall gradient in central Texas. I found that soils from the wet end of the precipitation gradient exhibited more plastic functional responses to altered water availability. However, soil bacterial community composition was resistant to changes in rainfall and dispersal, preventing functional acclimatization to precipitation regime. Together, the results of these experiments emphasize the potential for physiological plasticity or microevolutionary shifts within microbial populations to drive ecosystem carbon cycling under climate change.

Book Adaptation of Soil Fungi to Warming and Consequences for Decomposition and the Carbon Cycle

Download or read book Adaptation of Soil Fungi to Warming and Consequences for Decomposition and the Carbon Cycle written by Adriana L. Romero-Olivares and published by . This book was released on 2017 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studying soil carbon (C) losses and carbon dioxide (CO 2) feedbacks to the atmosphere under global climate change allows us to quantify and understand how our ecosystems are responding to warming. To accurately project the fate of the terrestrial C, we need to incorporate processes that are pivotal in shaping microbial communities that are responsible of processing the C in the soil. One of these processes is the evolutionary adaptation to warming which has been difficult to study because it may only be noticeable on the long term. The goal of my dissertation was to examine soil microbes, their response and adaptation to warming, and consequences to the C cycle. In Chapter 1, I synthesized data from 25 field warming experiments to assess the effect of microbial responses---relevant to the C cycle---to warming over time. I found that the effect of soil respiration decreases as warming progresses and explored the potential microbial-related causes of this decrease. In my second chapter, I experimentally adapted the model fungus Neurospora discreta to warming and analyzed physiological traits important for the C cycle before and after adaptation. I discovered that when N. discreta adapts to warming it allocates more resources to increase its fitness by producing more spores at the expense of biomass. I found that adaptation to warming is accompanied by increases in CO2 respiration potentially due to higher production of energetically expensive spores. In this chapter, I discussed the potential consequences for the terrestrial C if the soil microbial community adapts in a similar manner as N. discreta . Finally, in my third chapter, I quantified decomposition of specific C fractions in litter in a long-term field warming experiment. I found that the proportional losses of recalcitrant vs non-recalcitrant C was higher in warmed plots compared to control plots. Similarly, the ratio of microbial extracellular enzyme activities responsible for breaking down recalcitrant C was higher under warming compared to enzymes that break down non-recalcitrant C. Collectively, in my dissertation research I integrated the process of evolutionary adaptation of microbes to warming, thus providing an overview of the potential long-term effects of warming to decomposition and the C cycle.

Book Heterotrophic Soil Respiration in Warming Experiments

Download or read book Heterotrophic Soil Respiration in Warming Experiments written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The central objective of the proposed work was to develop a genomic approach (nucleic acid-based) that elucidates the mechanistic basis for the observed impacts of experimental soil warming on forest soil respiration. The need to understand the mechanistic basis arises from the importance of such information for developing effective adaptation strategies for dealing with projected climate change. Specifically, robust predictions of future climate will permit the tailoring of the most effective adaptation efforts. And one of the greatest uncertainties in current global climate models is whether there will be a net loss of carbon from soils to the atmosphere as climate warms. Given that soils contain approximately 2.5 times as much carbon as the atmosphere, a net loss could lead to runaway climate warming. Indeed, most ecosystem models predict that climate warming will stimulate microbial decomposition of soil carbon, producing such a positive feedback to rising global temperatures. Yet the IPCC highlights the uncertainty regarding this projected feedback. The uncertainty arises because although warming-experiments document an initial increase in the loss of carbon from soils, the increase in respiration is short-lived, declining to control levels in a few years. This attenuation could result from changes in microbial physiology with temperature. We explored possible microbial responses to warming using experiments and modeling. Our work advances our understanding of how soil microbial communities and their activities are structured, generating insight into how soil carbon might respond to warming. We show the importance of resource partitioning in structuring microbial communities. Specifically, we quantified the relative abundance of fungal taxa that proliferated following the addition of organic substrates to soil. We added glycine, sucrose, cellulose, lignin, or tannin-protein to soils in conjunction with 3-bromo-deoxyuridine (BrdU), a nucleotide analog. Active microbes absorb BrdU from the soil solution; if they multiply in response to substrate additions, they incorporate the BrdU into their DNA. After allowing soils to incubate, we extracted BrdU-labeled DNA and sequenced the ITS regions of fungal rDNA. Fungal taxa that proliferated following substrate addition were likely using the substrate as a resource for growth. We found that the structure of active fungal communities varied significantly among substrates. The active fungal community under glycine was significantly different from those under other conditions, while the active communities under sucrose and cellulose were marginally different from each other and the control. These results indicate that the overall community structure of active fungi was altered by the addition of glycine, sucrose, and cellulose and implies that some fungal taxa respond to changes in resource availability. The community composition of active fungi is also altered by experimental warming. We found that glycine-users tended to increase under warming, while lignin-, tannin/protein-, and sucrose-users declined. The latter group of substrates requires extracellular enzymes for use, but glycine does not. It is possible that warming selects for fungal species that target, in particular, labile substrates. Linking these changes in microbial communities and resource partitioning to soil carbon dynamics, we find that substrate mineralization rates are, in general, significantly lower in soils exposed to long-term warming. This suggests that microbial use of organic substrates is impaired by warming. Yet effects are dependent on substrate identity. There are fundamental differences in the metabolic capabilities of the communities in the control and warmed soils. These differences might relate to the changes in microbial community composition, which appeared to be associated with groups specialized on different resources. We also find that functional responses indicate temperature acclimation of the microbial community. There are distinct seasonal patterns and to long-term soil warming, with higher-temperature optima for soils exposed to warmer temperatures. To relate these changes within the microbial community to potential positive feedbacks between climate warming and soil respiration, we develop a microbial-enzyme model to simulate the responses of soil carbon to warming. We find that declines in microbial biomass and degradative enzymes can explain the observed attenuation of soil-carbon emissions in response to warming. Specifically, reduced carbon-use efficiency limits the biomass of microbial decomposers and mitigates loss of soil carbon. However, microbial adaptation or a change in microbial communities could lead to an upward adjustment of the efficiency of carbon use, counteracting the decline in microbial biomass and accelerating soil-carbon loss. We conclude that the soil-carbon response to climate warming depends on the efficiency of soil microbes in using carbon.

Book Microbiome Under Changing Climate

Download or read book Microbiome Under Changing Climate written by Ajay Kumar and published by Woodhead Publishing. This book was released on 2022-01-21 with total page 575 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microbiome Under Changing Climate: Implications and Solutions presents the latest biotechnological interventions for the judicious use of microbes to ensure optimal agricultural yield. Summarizing aspects of vulnerability, adaptation and amelioration of climate impact, this book provides an important resource for understanding microbes, plants and soil in pursuit of sustainable agriculture and improved food security. It emphasizes the interaction between climate and soil microbes and their potential role in promoting advanced sustainable agricultural solutions, focusing on current research designed to use beneficial microbes such as plant growth promoting microorganisms, fungi, endophytic microbes, and more. Changes in climatic conditions influence all factors of the agricultural ecosystem, including adversely impacting yield both in terms of quantity and nutritional quality. In order to develop resilience against climatic changes, it is increasingly important to understand the effect on the native micro-flora, including the distribution of methanogens and methanotrophs, nutrient content and microbial biomass, among others. - Demonstrates the impact of climate change on secondary metabolites of plants and potential responses - Incorporates insights on microflora of inhabitant soil - Explores mitigation processes and their modulation by sustainable methods - Highlights the role of microbial technologies in agricultural sustainability

Book Land Use Intensification

    Book Details:
  • Author : Saul Cunningham
  • Publisher : CSIRO PUBLISHING
  • Release : 2012-07-18
  • ISBN : 0643104097
  • Pages : 169 pages

Download or read book Land Use Intensification written by Saul Cunningham and published by CSIRO PUBLISHING. This book was released on 2012-07-18 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: There can be little doubt that there are truly colossal challenges associated with providing food, fibre and energy for an expanding world population without further accelerating already rapid rates of biodiversity loss and undermining the ecosystem processes on which we all depend. These challenges are further complicated by rapid changes in climate and its additional direct impacts on agriculture, biodiversity and ecological processes. There are many different viewpoints about the best way to deal with the myriad issues associated with land use intensification and this book canvasses a number of these from different parts of the tropical and temperate world. Chapters focus on whether science can suggest new and improved approaches to reducing the conflict between productive land use and biodiversity conservation. Who should read this book? Policy makers in regional, state and federal governments, as well as scientists and the interested lay public.

Book Soil Carbon Storage

    Book Details:
  • Author : Brajesh Singh
  • Publisher : Academic Press
  • Release : 2018-04-12
  • ISBN : 0128127678
  • Pages : 341 pages

Download or read book Soil Carbon Storage written by Brajesh Singh and published by Academic Press. This book was released on 2018-04-12 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil Carbon Storage: Modulators, Mechanisms and Modeling takes a novel approach to the issue of soil carbon storage by considering soil C sequestration as a function of the interaction between biotic (e.g. microbes and plants) and abiotic (climate, soil types, management practices) modulators as a key driver of soil C. These modulators are central to C balance through their processing of C from both plant inputs and native soil organic matter. This book considers this concept in the light of state-of-the-art methodologies that elucidate these interactions and increase our understanding of a vitally important, but poorly characterized component of the global C cycle. The book provides soil scientists with a comprehensive, mechanistic, quantitative and predictive understanding of soil carbon storage. It presents a new framework that can be included in predictive models and management practices for better prediction and enhanced C storage in soils. - Identifies management practices to enhance storage of soil C under different agro-ecosystems, soil types and climatic conditions - Provides novel conceptual frameworks of biotic (especially microbial) and abiotic data to improve prediction of simulation model at plot to global scale - Advances the conceptual framework needed to support robust predictive models and sustainable land management practices

Book Principles of Soil Microbiology

Download or read book Principles of Soil Microbiology written by Selman Abraham Waksman and published by . This book was released on 1927 with total page 972 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Microbial Temperature Dependencues in Soil   The Belowground Feedback to Climate Change

Download or read book Microbial Temperature Dependencues in Soil The Belowground Feedback to Climate Change written by Dániel Tájmel and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the Industrial Revolution, human activities have elevated atmospheric CO2 concentrations. The consequences of this include rising temperatures, shifts in precipitation patterns, and increased intensity and frequency of extreme weather events, such as heat waves and droughts. Elevated temperatures can accelerate microbial activity in soil, potentially resulting in an increased rate of soil organic matter (SOM) decomposition. This increased microbial decomposition may, in turn, lead to a release of CO2, contributing to a positive feedback loop amplifying climate warming. To understand the microbial feedback to warming, I studied the processes leading to carbon (C) accumulation through microbial growth and CO2 release via microbial respiration. I determined the temperature dependence of microbial growth and respiration to assess how these process rates change with altered temperatures. The results of this thesis indicate that (i) the microbial temperature dependence is not dependent on soil moisture. This validation through an empirical test is important, as most ecosystem models employ a distinct temperature dependence that operates independently of soil moisture. In addition, (ii) the temperature dependence of bacterial growth can become warm-shifted within one growing season due to a summer heat wave simulation in the field and with a similar trend for fungal growth. The warm-shifted bacterial growth temperature dependence fully recovered within a year and matched the temperature dependence at ambient conditions. These findings highlight the fast microbial responses to a heat wave and the long-lasting legacy of such extreme weather events. The results also indicate that (iii) the microbial temperature dependence varies systematically with environmental temperatures along a wide climate gradient in Europe. Microbial communities showed warm-shifted temperature dependences in warmer ecosystems and cold-shifted temperature dependences in colder areas. Finally, (iv) empirically determined microbial temperature dependences were incorporated into a dynamic vegetation model LPJ-GUESS. Specifically, separate temperature dependence for microbial growth and respiration were employed to represent C sequestration and emissions from soils in response to temperature variations. In addition, the microbial temperature dependences were allowed to adjust to the climate that they encounter. Therefore, the microbial thermal traits can become climate-specific and adjust to changes in thermal regimes.

Book The Soil and the Microbe

    Book Details:
  • Author : Selman A. Waksman
  • Publisher : Forgotten Books
  • Release : 2018-09-10
  • ISBN : 9781396091131
  • Pages : 274 pages

Download or read book The Soil and the Microbe written by Selman A. Waksman and published by Forgotten Books. This book was released on 2018-09-10 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from The Soil and the Microbe: An Introduction to the Study of the Microscopic Population of the Soil and Its Rôle in Soil Processes and Plant Growth The microorganisms, through their various activities, thus enable organic life to continue uninterruptedly on our planet. They keep in constant circulation the elements which are most essential for plant and animal life. They break down the complex organic molecules, built up by plants and animals, into the simple mineralized constituents, making the elements again available for the growth of cultivated and uncultivated plants which in their turn supply further food for animals. Just as man and other animals, as well as higher plants, find their habitat on the surface of the soil or immediately below it, so do the microbes live largely within the upper few inches of the earth's crust, where they carry out their important activities, supplying a continuous stream of nutrients in an available form for the growth of higher plants. This surface pellicle of the earth is thus found to be the seat of numerous processes of incalculable importance in the life of man, animals, and plants, enabling them to carry out their normal existence on our planet. Just as man and animals are determined in their development by the supply of plant food, so is the growth of plants determined by the activities of microorganisms in the soil. The microbes were probably among the first living organisms which appeared on our planet millions of years ago. Although their presence in ancient rocks is largely speculative, it is reasonable to assume, from an appreciation of their specific physiological processes, that they may have lived normally on the earth long before it was a fit habitat for higher plants and animals. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Book Mass Spectrometry of Soils

Download or read book Mass Spectrometry of Soils written by Thomas Boutton and published by CRC Press. This book was released on 1996-05-30 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work provides detailed coverage of the applications of proven spectometric techniques in soil science. It presents analytical approaches important in the study of pool sizes and the dynamics of macro- and micronutrients, the structure and function of soil organic matter, and the co-evolution of soils, plant communities and climate. Interdisciplinary perspectives from soil science, ecology, geology, chemistry, biogeochemistry, agronomy and physics, are offered.

Book The Ecology of Plant Litter Decomposition in Stream Ecosystems

Download or read book The Ecology of Plant Litter Decomposition in Stream Ecosystems written by Christopher M. Swan and published by Springer Nature. This book was released on 2021-08-01 with total page 523 pages. Available in PDF, EPUB and Kindle. Book excerpt: With almost 90% of terrestrial plant material entering the detrital pool, the processing of this significant carbon source is a critical ecosystem function to understand. Riverine ecosystems are estimated to receive, process and transport nearly 1.9 Pg of terrestrial carbon per year globally, highlighting the focus many freshwater ecologists have on the factors that explain decomposition rates of senesced plant material. Since Webster and Benfield offered the first comprehensive review of these factors in 1986, there has been an explosion of research addressing key questions about the ecological interactions at play. Ecologists have developed field and laboratory techniques, as well as created global scale collaborations to disentangle the many drivers involved in the decomposition process. This book encapsulates these 30+ years of research, describing the state of knowledge on the ecology of plant litter decomposition in stream ecosystems in 22 chapters written by internationally renowned experts on the subject.

Book Manual for Soil Analysis   Monitoring and Assessing Soil Bioremediation

Download or read book Manual for Soil Analysis Monitoring and Assessing Soil Bioremediation written by Rosa Margesin and published by Springer Science & Business Media. This book was released on 2005-12-15 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents detailed descriptions of methods for evaluating, monitoring and assessing bioremediation of soil contaminated with organic pollutants or heavy metals. Traditional soil investigation techniques, including chemical, physical and microbiological methods, are complemented by the most suitable modern methods, including bioreporter technology, immunological, ecotoxicological and molecular assays. Step-by-step procedures, lists of required equipment and reagents and notes on evaluation and quality control allow immediate application

Book Responses of Two Nonlinear Microbial Models to Warming and Increased Carbon Input

Download or read book Responses of Two Nonlinear Microbial Models to Warming and Increased Carbon Input written by and published by . This book was released on 2016 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: A number of nonlinear microbial models of soil carbon decomposition have been developed. Some of them have been applied globally but have yet to be shown to realistically represent soil carbon dynamics in the field. A thorough analysis of their key differences is needed to inform future model developments. In this paper, we compare two nonlinear microbial models of soil carbon decomposition: one based on reverse Michaelis-Menten kinetics (model A) and the other on regular Michaelis-Menten kinetics (model B). Using analytic approximations and numerical solutions, we find that the oscillatory responses of carbon pools to a small perturbation in their initial pool sizes dampen faster in model A than in model B. Soil warming always decreases carbon storage in model A, but in model B it predominantly decreases carbon storage in cool regions and increases carbon storage in warm regions. For both models, the CO2 efflux from soil carbon decomposition reaches a maximum value some time after increased carbon input (as in priming experiments). This maximum CO2 efflux (Fmax) decreases with an increase in soil temperature in both models. However, the sensitivity of Fmax to the increased amount of carbon input increases with soil temperature in model A but decreases monotonically with an increase in soil temperature in model B. These differences in the responses to soil warming and carbon input between the two nonlinear models can be used to discern which model is more realistic when compared to results from field or laboratory experiments. Lastly, these insights will contribute to an improved understanding of the significance of soil microbial processes in soil carbon responses to future climate change.

Book Standard Soil Methods for Long Term Ecological Research

Download or read book Standard Soil Methods for Long Term Ecological Research written by G. Philip Robertson and published by Oxford University Press. This book was released on 1999-10-28 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: Standardized methods and measurements are crucial for ecological research, particularly in long-term ecological studies where the projects are by nature collaborative and where it can be difficult to distinguish signs of environmental change from the effects of differing methodologies. This second volume in the Long-Term Ecological Research (LTER) Network Series addresses these issues directly by providing a comprehensive standardized set of protocols for measuring soil properties. The goal of the volume is to facilitate cross-site synthesis and evaluation of ecosystem processes. Chapters cover methods for studying physical and chemical properties of soils, soil biological properties, and soil organisms, and they include work from many leaders in the field. The book is the first broadly based compendium of standardized soil measurement methods and will be an invaluable resource for ecologists, agronomists, and soil scientists.