Download or read book Soil Microbial Enzyme Responses to Changes in Temperature and Nutrient Additions Across Hawaiian Gradients in Mineralogy and Nutrient Availability written by Taylor Leigh McCleery and published by . This book was released on 2014 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microbial enzyme activities are the direct agents of organic matter decomposition, and thus play a crucial role in global C (C) cycling. Global change factors like anthropogenic nutrient inputs and warming have the potential to alter the activities of these enzymes, with background site conditions likely driving responses. We hypothesized that enzyme activities in sites with high background soil nutrient and/or C availability would be less sensitive to nutrient additions than nutrient-poor sites. We also hypothesized that sites poor in nutrients and/or C would show greater sensitivity to changes in temperature. To test our hypotheses we used long- and short-term nutrient additions combined with laboratory temperature incubations to assess changes in enzyme activities for 8 common soil enzymes that acquire nitrogen (N), phosphorus (P) and C from organic matter. We collected mineral soils (0-10 cm depth) from 8 Hawaiian sites that provided maximum variation in nutrient availability and background soil C. Soils were sieved, pooled by site, and homogenized prior to a laboratory addition of a simple C (sucrose), N, and/or P in full factorial design. The 8 soils also were incubated at 7 temperatures from 4 - 40 ðC. We found that the laboratory fertilizations altered enzyme activities, and that temperature sensitivities varied significantly among sites. Across the 8 sites, laboratory sucrose+N and sucrose+NP additions increased C-, N-, and P- acquiring enzymes activities (p
Download or read book What s the Holdup written by Ruth Whittington and published by . This book was released on 2019 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: Arctic ecosystems contain globally important terrestrial carbon stocks, and their temperatures are rising at twice global rates. While increasing temperatures lead to faster decomposition and carbon mineralization rates, predicting the magnitude and future patterns of soil respiration is difficult due to multiple interacting direct and indirect effects. In particular, we lack mechanistic data on how low temperatures impact extracellular enzyme activities and thereby determine carbon supply rates to respiration. For this research, I performed two laboratory soil incubations designed to measure the temperature responses of enzymes catalyzing the terminal steps in Arctic tundra soil organic matter depolymerization. These experiments were designed to first characterize microbial activity responses to temperature based on cumulative carbon loss, and then to identify how substrate and nutrient availability mediate indirect temperature responses. In the first experiment, tundra soils were incubated across a temperature gradient from 4 - 20 °C and subsequently harvested at four time points at comparable levels of cumulative carbon loss. Comparing temperature effects on respiration rates as they changed with greater substrate depletion, respiration temperature sensitivity declined over time, likely due to declining substrate availability at higher temperatures. In contrast, enzyme temperature sensitivity increased over time, an apparent consequence of increased enzyme production at higher temperatures. These results indicate that carbon flow from depolymerization may not be high enough to sustain microbial activity below 10 °C and may explain observations of unexpectedly high increases in soil respiration with temperature in this range. In a second experiment, labile carbon was added with and without nutrients to tundra soils incubated at 8 and 16 °C and subsequently harvested at three points based on cumulative carbon loss from control soils. Respiration temperature sensitivity increased following labile carbon addition, indicating low substrate availability suppressed temperature responses from control soils. Temperature limitations to enzyme production persisted across all treatments, suggesting limitations to enzyme production may be due to lower microbial demand at low temperatures. Overall, results from this research demonstrate a number of indirect temperature effects on enzyme production and carbon availability that are currently unaccounted for in predictive Earth system models. Furthermore, they suggest that both enzyme production and activity are likely to increase as Arctic soils warm, two mechanisms by which temperature rise may increase carbon transfer from tundra soils to the atmosphere.
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:
Download or read book Forest and Rangeland Soils of the United States Under Changing Conditions written by Richard V. Pouyat and published by Springer Nature. This book was released on 2020-09-02 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book synthesizes leading-edge science and management information about forest and rangeland soils of the United States. It offers ways to better understand changing conditions and their impacts on soils, and explores directions that positively affect the future of forest and rangeland soil health. This book outlines soil processes and identifies the research needed to manage forest and rangeland soils in the United States. Chapters give an overview of the state of forest and rangeland soils research in the Nation, including multi-decadal programs (chapter 1), then summarizes various human-caused and natural impacts and their effects on soil carbon, hydrology, biogeochemistry, and biological diversity (chapters 2–5). Other chapters look at the effects of changing conditions on forest soils in wetland and urban settings (chapters 6–7). Impacts include: climate change, severe wildfires, invasive species, pests and diseases, pollution, and land use change. Chapter 8 considers approaches to maintaining or regaining forest and rangeland soil health in the face of these varied impacts. Mapping, monitoring, and data sharing are discussed in chapter 9 as ways to leverage scientific and human resources to address soil health at scales from the landscape to the individual parcel (monitoring networks, data sharing Web sites, and educational soils-centered programs are tabulated in appendix B). Chapter 10 highlights opportunities for deepening our understanding of soils and for sustaining long-term ecosystem health and appendix C summarizes research needs. Nine regional summaries (appendix A) offer a more detailed look at forest and rangeland soils in the United States and its Affiliates.
Download or read book Bibliography of Agriculture with Subject Index written by and published by . This book was released on 2000 with total page 830 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biochar for Environmental Management written by Johannes Lehmann and published by Routledge. This book was released on 2012-05-16 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biochar is the carbon-rich product when biomass (such as wood, manure or crop residues) is heated in a closed container with little or no available air. It can be used to improve agriculture and the environment in several ways, and its stability in soil and superior nutrient-retention properties make it an ideal soil amendment to increase crop yields. In addition to this, biochar sequestration, in combination with sustainable biomass production, can be carbon-negative and therefore used to actively remove carbon dioxide from the atmosphere, with major implications for mitigation of climate change. Biochar production can also be combined with bioenergy production through the use of the gases that are given off in the pyrolysis process. This book is the first to synthesize the expanding research literature on this topic. The book's interdisciplinary approach, which covers engineering, environmental sciences, agricultural sciences, economics and policy, is a vital tool at this stage of biochar technology development. This comprehensive overview of current knowledge will be of interest to advanced students, researchers and professionals in a wide range of disciplines.
Download or read book Ocean Acidification written by National Research Council and published by National Academies Press. This book was released on 2010-09-14 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Bibliography of Agriculture written by and published by . This book was released on 1972 with total page 1226 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microbial Growth Kinetics written by N.S. Panikov and published by Springer Science & Business Media. This book was released on 1995-03-31 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microbial Growth Kinetics opens with a critical review of the history of microbial kinetics from the 19th century to the present day. The results of original investigations into the growth of soil microbes in both laboratory and natural environments are summarised. The book emphasises the analysis of complex dynamic behaviour of microorganism populations. Non-steady states and unbalanced growth, multiple limitation, survival under starvation, differentiation, morphological variability, colony and biofilm growth, mixed cultures and microbial population dynamics in soil are all examined. Mathematical models are proposed which give mechanistic explanations to many features of microbial growth. The book takes general kinetic principles and their ecological applications and presents them in a way specifically designed for the microbiologist. This in itself is unusual but taken with the book's fascinating historical overview and the many fresh and sometimes controversial ideas expressed, this book is a must for all advanced students of microbiology and researchers in microbial ecology and growth.
Download or read book Bibliography of Agriculture written by and published by . This book was released on 1991 with total page 1810 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Carbon Cycling in Hawaiian Soils written by Katherine Elizabeth Grant and published by . This book was released on 2019 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volcanic soils can effectively store organic carbon (OC) for time scales of 10^2 to 10^4 of years. Previous work suggests that carbon-mineral interactions play a key role in the long term persistence of OC. This dissertation examines a transect on Kohala Mountain (Island of Hawai`i), where soils have formed on a 400 ka basaltic substrate. Along the transect, trade winds drive a precipitation gradient leading to systematic changes in soil moisture, pH, and mineralogy. To examine the persistence of the SOC as soil conditions change, I utilized a series of inorganic and organic geochemical techniques, including metal analysis, carbon analysis, and pyrolysis-oxidation experiments. I used high resolution radiocarbon measurements on bulk soils, thermal fractions collected from ramped pyrolysis/oxidation (RPO), and compound-specific lipid biomarkers to measure the complex differences in the age from bulk to compound scale. This approach allowed for the interpretation of incremental changes in soil carbon energetics and age along the climate gradient. Soil organic horizons show modern radiocarbon values across the gradient, while deeper mineral soils yield variable but generally significantly older radiocarbon ages. In the wetter part of the climate gradient the soils are significantly depleted in iron oxides. The Fe-poor mineral subsoils have much younger 14C ages than in equivalent soils that retain Fe. Activation energy distributions p(0,E) from RPO data are calculated in each sample. I found that while the age gradient of the thermal fractions was relatively flat in all samples, the activation energies between organic horizons and mineral horizons differed. Mineral interactions dominate the activation energy signal resulting in a shift to a lower activation energies in subsoils verse organic horizons. This indicates two distinct mechanisms of contributing to the OC persistence across the climate gradient. The increase in activation energy in the organic horizons indicates an increased temperature sensitivity of this younger material, while mineral surface interaction decreases the OC`s vulnerability to degradation. Lipid biomarkers were used to constrain the end members of SOC at these sites. Long-chain n-alkanoic acids were older than both RPO fractions and bulk 14C values. This effect was site-specific, so irrespective of actual age, plant waxes are much younger in soils where Fe is no longer abundant indicating Fe plays an important function in OC stabilization in volcanic soils across scales, from single compounds to bulk OC. Over all I find that mineral weathering has a strong effect on the persistence of soil OC. The presence of Fe minerals in subsurface mineral horizons is associated with carbon that is stabilized for > 10,000 years. The data are consistent with a major role for mineral stabilization of old organic carbon in these volcanic soils. The role of oxidized iron minerals appears to be particularly important. Because the stability of Fe-oxides is climate dependent, the storage of large amounts of old carbon in deep soil mineral horizons is potentially vulnerable to climate change.
Download or read book Soil Enzymology written by Girish Shukla and published by Springer Science & Business Media. This book was released on 2010-10-17 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil enzymes are one of the vital key mediators involved in nutrient recycling and the decomposition of organic matter and thereby in maintaining soil quality and fertility. This Soil Biology volume covers the various facets of soil enzymes, such as their functions, biochemical and microbiological properties and the factors affecting their activities. Enzymes in the rhizosphere, in forest soils, and in volcanic ash-derived soils are described. Soil enzymes covered include phosphohydrolases, lignocellulose-degrading enzymes, phenol oxidases, fungal oxidoreductases, keratinases, pectinases, xylanases, lipases and pectinases. Several chapters treat the soil enzymatic activities in the bioremediation of soils contaminated with pesticides and pollutants such as oil, chlorinated compounds, synthetic dyes and aromatic hydrocarbons. The role of soil enzymes as bioindicators is a further important topic addressed.
Download or read book Litter Decomposition a Guide to Carbon and Nutrient Turnover written by and published by Academic Press. This book was released on 2005-11-22 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: Litter Decomposition describes one of the most important processes in the biosphere - the decay of organic matter. It focuses on the decomposition process of foliar litter in the terrestrial systems of boreal and temperate forests due to the greater amount of data from those biomes. The availability of several long-term studies from these forest types allows a more in-depth approach to the later stages of decomposition and humus formation. Differences between the decay of woody matter and foliar litter is discussed in detail and a different pattern for decomposition is introduced. While teachers and students in more general subjects will find the most basic information on decomposition processes in this book, scientists and graduate students working on decomposition processes will be entirely satisfied with the more detailed information and the overview of the latest publications on the topic as well as the methodological chapter where practical information on methods useful in decomposition studies can be found. Abundant data sets will serve as an excellent aid in teaching process and will be also of interest to researchers specializing in this field as no thorough database exists at the moment. Provides over 60 tables and 90 figures Offers a conceptual 3-step model describing the different steps of the decomposition process, demonstrating changes in the organic-chemical structure and nutrient contents Includes a synthesis of the current state of knowledge on foliar litter decomposition in natural systems Integrates more traditional knowledge on organic matter decomposition with current problems of environmental pollution, global change, etc. Details contemporary knowledge on organic matter decomposition
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2003 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Meta Win 2 0 written by Michael S. Rosenberg and published by Sinauer Associates Incorporated. This book was released on 1999-10-01 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: MetaWin, first published in 1997, allows the user to easily carry out all common meta-analysis calculations on multiple independent studies from a wide variety of disciplines, including medicine, ecology, and the social sciences. Version 2.0 allows users to calculate any of six different effect sizes (vs. two, as in Version 1.0) from their data, and includes its own spreadsheet editor and statistical calculator. The analysis routine is greatly expanded, and graphics (e.g., funnel plots, histograms, etc.) have been added.
Download or read book Inputs of Nutrients and Pollutants to Hawaiian Coastal Waters from Submarine Groundwater Discharge written by Karen Lisa Knee and published by Stanford University. This book was released on 2010 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Submarine groundwater discharge (SGD) is a spatially pervasive phenomenon that adds freshwater, nutrients, dissolved metals, bacteria, and other constituents to the coastal ocean. This dissertation investigated SGD-related inputs of nutrients and fecal indicator bacteria (Escherichia coli and Enterococcus sp.) to coastal waters in two Hawaiian locations, the north shore of Kaua'i and the Kona coast of Hawai'i. Concentrations of caffeine, which has been used previously as a wastewater tracer, were measured in groundwater and surface water on the north shore of Kaua'i. Both study areas have relatively light levels of urban and agricultural development, and maintaining good water quality is essential for their tourism-based economies, coral reefs, fisheries, and traditional way of life. Radium (Ra), an element with naturally elevated concentrations in coastal groundwater, was used as an SGD tracer and a mass-balance approach was used to quantify SGD. On the north shore of Kaua'i, agriculture was associated with higher nitrate + nitrite concentrations in the fresh SGD component, while phosphate and silica appeared to be controlled by geological differences in aquifer substrate. High ammonium concentrations in the fresh SGD component at one site may have been caused by a leaky cesspool. In Kona, no relation between urban development or agriculture and groundwater nutrient concentrations was observed, but bare lava rock was associated with higher nitrate + nitrite and silica concentrations in fresh SGD. Sites closer to golf courses also had higher nitrate + nitrite concentrations. Conservative estimates of total SGD on the north shore of Kaua'i ranged from 1.3 to 7.8 L per meter per minute, or up to 10% of Hanalei River discharge, and SGD contributed significant nitrate + nitrite inputs to Hanalei Bay. Estimates of SGD in Kona ranged from 5 to 1200 L per meter per minute, with between 10 and 100% of the brackish SGD comprised by the fresh SGD component. SGD-related water and nutrient fluxes on the Kona Coast -- where no rivers and streams are present -- were large compared to those reported for other sites worldwide. Caffeine concentrations in environmental waters on the north shore of Kaua'i ranged from 0-88 ng/L, on the low end of what has been reported for other locations. Metribuzin, an herbicide, was also detected at concentrations from 4-11 ng/L in five groundwater and surface water samples. A sensitivity analysis of Ra-based methods of estimating water ages and coastal mixing rates revealed that water ages shorter than 3 d cannot be estimated with confidence using Ra-based methods, even if the only uncertainty considered is analytical error. In conclusion, this dissertation provides new data about SGD and related inputs of nutrients and bacteria to Hawaiian coastal waters, suggests that even low levels of development may influence nutrient concentrations in coastal groundwater, presents the first caffeine concentrations measured in environmental water samples collected in a tropical setting, and explores the limits of applicability of Ra-based methods of estimating water ages and coastal mixing rates, providing guidance for researchers conducting Ra-based SGD studies in the future.
Download or read book Response of Soil Enzyme Activities and Carbon Utilization Efficiency to Changes in Temperature written by Jessica Megan Steinweg and published by . This book was released on 2007 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
