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Experimental Chronic Dry Atmospheric Nitrogen N Deposition Causes A Change In Soil Microbial Communities In Southern California Semi Arid Shrublands
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Book Synopsis Experimental Chronic Dry Atmospheric Nitrogen (N) Deposition Causes a Change in Soil Microbial Communities in Southern California Semi-Arid Shrublands by : Timothy Grant
Download or read book Experimental Chronic Dry Atmospheric Nitrogen (N) Deposition Causes a Change in Soil Microbial Communities in Southern California Semi-Arid Shrublands written by Timothy Grant and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Global nitrogen (N) deposition has increased since the beginning of the Industrial Revolution due to anthropogenic influences such as the burning of fossil fuels and application of N fertilizer. Increased industrialization is expected to continue to escalate the quantity of N released to ecosystems and the atmosphere. Soil microbial communities are susceptible to this increase in N, as microbial activity can be limited by N and these communities are known to regulate biogeochemical cycles. In this study, the response of bacterial functional groups (FG) to N addition (> 50 Kg N ha-1 yr-1) was quantified in Southern California semi-arid topsoil (0-10 cm). Soil physical-chemical properties and enzymatic activities were also quantified to further understand the direct/indirect effects of N addition on bacterial FG. Experimental N addition significantly increased the abundance N-fixing, chitinolytic, and starch degrading bacteria in semi-arid soils; while increasing N-mineralizing and denitrifying bacteria in coastal sage shrub (CSS) soil. N input also decreased the abundance metal redox bacteria in CCS soil and decreased nitrifying bacteria in chaparral soil. Furthermore, N addition increased the abundance of copiotrophic bacteria (ie: Proteobacteria, Bacteroidetes, and Firicutes) and decreased the abundance of oligotrophic bacteria (ie: Acidobacteria) in semi-arid soils. Canonical correspondence analysis revealed that the majority of FG were influenced by soil pH and extractable nitrate, which were also significantly altered by N addition. Results indicated excessive N input directly and indirectly affected the composition of the soil bacterial community. Understanding the response of the microbial community to N additions is important in predicting ecosystem functionality and stability as anthropogenic N deposition increases.
Book Synopsis Ecosystems of California by : Harold Mooney
Download or read book Ecosystems of California written by Harold Mooney and published by Univ of California Press. This book was released on 2016-01-19 with total page 1009 pages. Available in PDF, EPUB and Kindle. Book excerpt: This long-anticipated reference and sourcebook for California’s remarkable ecological abundance provides an integrated assessment of each major ecosystem type—its distribution, structure, function, and management. A comprehensive synthesis of our knowledge about this biologically diverse state, Ecosystems of California covers the state from oceans to mountaintops using multiple lenses: past and present, flora and fauna, aquatic and terrestrial, natural and managed. Each chapter evaluates natural processes for a specific ecosystem, describes drivers of change, and discusses how that ecosystem may be altered in the future. This book also explores the drivers of California’s ecological patterns and the history of the state’s various ecosystems, outlining how the challenges of climate change and invasive species and opportunities for regulation and stewardship could potentially affect the state’s ecosystems. The text explicitly incorporates both human impacts and conservation and restoration efforts and shows how ecosystems support human well-being. Edited by two esteemed ecosystem ecologists and with overviews by leading experts on each ecosystem, this definitive work will be indispensable for natural resource management and conservation professionals as well as for undergraduate or graduate students of California’s environment and curious naturalists.
Book Synopsis Interaction Between Nitrogen and Carbon Availability on Microbial Activity and Biomass in Chaparral Soils of Southern California by : Kali C. Holt
Download or read book Interaction Between Nitrogen and Carbon Availability on Microbial Activity and Biomass in Chaparral Soils of Southern California written by Kali C. Holt and published by . This book was released on 2016 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: A large portion of nitrogen deposition on southern California's chaparral and coastal sage scrub (CSS) is due to anthropogenic sources. The implications of increasing soil nitrogen, and the relationship between soil nitrogen and carbon on soil microorganism growth and activity, are not well understood. Possible interactions between N inputs and soil C availability on soil respiration and microbial biomass were assessed in chaparral and CSS plots that have been experimentally treated with N for about 12 years. Soil (microbial + autotrophic) respiration and microbial biomass were measured in four conditions: in plots exposed to added and ambient N, and within these plots, under shrubs and in open spaces, which represent microsites with differing N and C availability. We measured soil respiration and microbial biomass in these conditions every 3 months for a period of 1 year to test the hypothesis that respiration and microbial biomass would (1) increase in plots with higher C and N availability and (2) be higher during the winter and spring because of higher soil water availability. Our results indicate that soil respiration was significantly higher under shrubs but not in plots exposed to added N while microbial biomass was significantly higher in plots exposed to added N but not under shrubs. Soil respiration and microbial biomass were higher in the summer months than during the winter and spring months. These results were observed for both CSS and chaparral, indicating that the effects of long-term N exposure on soil microbial activity and biomass may be general for semiarid shrublands. While speculative, the N-induced increase in microbial biomass, without an increase in activity (respiration), suggests that N exposure has altered the soil microbial community. A change in the soil microbial community has important implications for soil N and C cycling and storage, especially in semi-arid chaparral ecosystems subject to large inputs of atmospheric N.
Book Synopsis Effects of Nitrogen Deposition on Nitric Oxide (NO) Efflux of Chaparral Soil in Southern California by : Catherine DeFotis
Download or read book Effects of Nitrogen Deposition on Nitric Oxide (NO) Efflux of Chaparral Soil in Southern California written by Catherine DeFotis and published by . This book was released on 2013 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large amounts of nitrogen (N) are being deposited in urban areas of southern California, which are altering the carbon (C) and N cycling of semi-arid shrubland ecosystems. It is possible that these N inputs are exceeding biotic demand, leading to "N saturation" and increasing the losses of N from leaching and gaseous efflux. N input to soil increases the microbial process of nitrification, which releases nitric oxide (NO) into the atmosphere as a byproduct. The production of NO in chaparral soils is not fully characterized and more experimentation is needed to understand the environmental controls on NO flux from semi-arid soils. Thus, a laboratory incubation experiment was executed to see how NO efflux of chaparral soil varied as function of N addition (0-5 gN/m2) under various soil temperature (0-40°C) and moisture conditions (10.5-72.7%). Based on limited research, I hypothesized that the NO efflux of southern California chaparral soils would i) increase as a function of N addition, ii) present an optimum response as a function of soil moisture, and iii) increase as an exponential function of temperature. Results indicate that NO efflux increased linearly with N addition, supporting the hypothesis that an increase in N availability will increase NO efflux. NO efflux also increased as a function of soil temperature and was well-described using the Arrhenius model, supporting hypothesis 3, and the NO efflux followed an optimum response as a function of soil moisture, supporting hypothesis 2. In general, the greatest NO efflux was observed from soil samples treated with 5 gN/m2 (NH4)2SO4, brought to 25% water-filled pore space (WFPS), and at a temperature of 34.4°C. There was high sensitivity to temperature changes between 0 and 5 gN/m2 (NH4)2SO4 and in soil moistures
Book Synopsis Soil Nutrient Cycling and Storage in Semi-arid Shrubland Ecosystems Exposed to High N Deposition in Southern California by : Gypsiana Zorba-Denison
Download or read book Soil Nutrient Cycling and Storage in Semi-arid Shrubland Ecosystems Exposed to High N Deposition in Southern California written by Gypsiana Zorba-Denison and published by . This book was released on 2006 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Effects of Long-term Atmospheric Nitrogen Deposition on Extracellular Enzyme Activity in Semi-arid Shrubland Soil by : Andrea Fenner
Download or read book Effects of Long-term Atmospheric Nitrogen Deposition on Extracellular Enzyme Activity in Semi-arid Shrubland Soil written by Andrea Fenner and published by . This book was released on 2015 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anthropogenic nitrogen (N) deposition represents a significant input of N into coastal sage scrub (CSS) and chaparral ecosystems of Southern California. Increased N deposition has the potential to alter the decomposition rate of soil organic matter (SOM) in N limited terrestrial ecosystems through altering the enzymatic activity of soil microorganisms that play a key role in the decomposition process. Since few reports have examined the effects of N deposition on the enzymatic activity of soil microorganisms in semi-arid shrublands, this study aimed to determine how N deposition affects the enzymatic activity of microorganisms that drive the decomposition process. Based on results from other ecosystems, we hypothesized that added N would suppress the enzymatic activity of ligninolytic enzymes (phenol oxidase and peroxidase) and would increase the enzymatic activity of the cellulolytic enzyme, p-Nitrophenyl-ß-D-glucosidase. Enzyme assays were conducted on soil samples collected from eight plots located at two field sites where N addition experiments had been conducted over the last 10 years. Field sites were composed of four unmanipulated control plots and four experimental plots, which received 50 kg N/ha annually. Data collected from the chaparral site indicated that there was a significant difference in peroxidase activity between control and N treatment plots (p-value= 0.016) and a significant difference over time for control and treatment plots in p-Nitrophenyl-ß-D-glucosidase activity (p-value= 0.032) and phenol oxidase activity (p-value= 0.003). Data collected from the CSS site indicated that there was a significant difference in peroxidase activity between control and N treatment plots (p-value= 0.010) and a significant difference over time in peroxidase activity (p-value= 0.001). In addition, there was a significant difference over time for control and treatment plots in p-Nitrophenyl-ß-D-glucosidase activity (p-value= 0.0003) and phenol oxidase activity (p-value= 0.001). The decrease in p-Nitrophenyl-ß-D-glucosidase activity and the lack of suppression of phenol oxidase in some added N plots when compared to control plots differed from our initial hypothesis and was inconsistent with other findings from previous literature. However, much of the findings from previous literature focus on how N deposition affects the activity of enzymes involved in the decomposition of litter not SOM, and because peroxidase may be important in the degradation of older structural C, which is typical of soils, it may not be too surprising that our results indicate that only peroxidase was significantly affected by N addition. Little is known about how N deposition affects the enzymatic activity of enzymes involved in the decomposition of SOM, and whether the activity of these enzymes follow the same patterns of those involved in the decomposition of litter. Findings from this study may provide the insight needed to determine how N deposition affects the activity of enzymes involved in the decomposition of SOM thus, giving us a better understanding of how N deposition affects decomposition rates of SOM in semi-arid shrublands.
Book Synopsis Responses of Nitrifying Microbes in Southern California Native Plant Communities to Additions of Nitrogen by : Robert R. Mustard
Download or read book Responses of Nitrifying Microbes in Southern California Native Plant Communities to Additions of Nitrogen written by Robert R. Mustard and published by . This book was released on 2008 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The European Nitrogen Assessment by : Mark A. Sutton
Download or read book The European Nitrogen Assessment written by Mark A. Sutton and published by Cambridge University Press. This book was released on 2011-04-14 with total page 665 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presenting the first continental-scale assessment of reactive nitrogen in the environment, this book sets the related environmental problems in context by providing a multidisciplinary introduction to the nitrogen cycle processes. Issues of upscaling from farm plot and city to national and continental scales are addressed in detail with emphasis on opportunities for better management at local to global levels. The five key societal threats posed by reactive nitrogen are assessed, providing a framework for joined-up management of the nitrogen cycle in Europe, including the first cost-benefit analysis for different reactive nitrogen forms and future scenarios. Incorporating comprehensive maps, a handy technical synopsis and a summary for policy makers, this landmark volume is an essential reference for academic researchers across a wide range of disciplines, as well as stakeholders and policy makers. It is also a valuable tool in communicating the key environmental issues and future challenges to the wider public.
Book Synopsis Responses of Microbial Communities to Atmospheric Nitrogen Deposition Within Different Soil Horizons in High Arctic Tundra by : Aimeric Blaud
Download or read book Responses of Microbial Communities to Atmospheric Nitrogen Deposition Within Different Soil Horizons in High Arctic Tundra written by Aimeric Blaud and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Arctic environments are subject to acute nitrogen deposition events, in which 40% or more of annual atmospheric N input can be deposited as acidic rainfall in less than one week. The overall aim of this research was to investigate the impact of acute N deposition events upon soil microbial communities in High Arctic tundra. A plot scale field experiment, established on the High Arctic tundra (Ny-Ålesund, Svalbard), and a microcosm experiment, were used to simulate acute N deposition over the summer by the application of NH4NO3 solution at ~pH 4, at rates of 0.4, 4 and 12 kg N ha-1 yr-1. Changes in soil characteristics were measured on soil samples from the organic and mineral horizons. Variation in the structure and abundance of bacterial, archaeal, and fungal communities and in the presence and abundance of N-cycling functional guilds were investigated using molecular (DNA)-based approaches such as Terminal Restriction Fragment Polymorphism (T-RFLP) and quantitative-PCR. T-RFLP analysis revealed significant (P
Book Synopsis EFFECTS OF ALTERNATE PRECIPITATION PATTERNS ON SOIL MICROBIAL COMMUNITIES IN A CALIFORNIA GRASSLAND by : Karelyn Cruz Martinez
Download or read book EFFECTS OF ALTERNATE PRECIPITATION PATTERNS ON SOIL MICROBIAL COMMUNITIES IN A CALIFORNIA GRASSLAND written by Karelyn Cruz Martinez and published by . This book was released on 2010 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anthropogenic changes in climatic conditions, such as the timing and amount of rainfall, can have profound biotic and abiotic consequences on grassland ecosystems. Grassland's plant and animal phenology are adapted to the ecosystem's wet and cold winters and hot and dry summers and changes to this pattern will have profound consequences in aboveground community structure. Changes in climatic conditions and aboveground communities will also affect the soil biogeochemistry and microbial communities. Soil microbes are an essential component in ecosystem functioning, as they are the key players in nutrient cycling. This thesis investigated the direct and indirect effects of climate change on the structure, composition and abundance of grassland soil microbial communities. The research used the high-throughput technique of 16S rRNA microarrays (Phylochip) to detect changes in the abundances and activities of soil bacterial and archaeal taxa in response to changes in precipitation patterns, aboveground plant communities, and soil environmental conditions. The research took advantage of alongterm climate change experiment that simulated both an increase and an extension of the current winter season in northern California. Five years into the experiment, soil samples and aboveground plant diversity were collected before and after each treatment for two consecutive years. The variability in soil microbial communities after natural wet-dry rainfall events was also investigated. Results showed that, at the community level, soil microbial communities are very robust and resilient to intensified or extended rainfalls during the winter but under extreme and unusual weather events their community structure can be altered. On the other hand, an increased in moss biomass in the plots that received additional water during the spring and fluctuations in soil moisture content (precipitation models and wet-dry patterns) caused changes in soil environmental conditions which in turn affected the activity and abundance of some microbial taxa/guilds. Soil organic carbon and inorganic nitrogen were among the environmental variables that correlated the most with these changes in microbial groups. Considering the great importance soil microbes have in ecosystem functioning, the approach developed here will find application for monitor responses of keystone microbial species/guilds to future changes in climatic conditions. These responses should be taken in consideration for future soil management and conservation practices, and the impacts included in future climate change models.
Book Synopsis Effect of Increasing Nitrogen Deposition on Soil Microbial Communities by :
Download or read book Effect of Increasing Nitrogen Deposition on Soil Microbial Communities written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing nitrogen deposition, increasing atmospheric CO2, and decreasing biodiversity are three main environmental changes occurring on a global scale. The BioCON (Biodiversity, CO2, and Nitrogen) ecological experiment site at the University of Minnesota's Cedar Creek Ecosystem Science Reserve started in 1997, to better understand how these changes would affect soil systems. To understand how increasing nitrogen deposition affects the microbial community diversity, heterogeneity, and functional structure impact soil microbial communities, 12 samples were collected from the BioCON plots in which nitrogenous fertilizer was added to simulate the effect of increasing nitrogen deposition and 12 samples from without added fertilizer. DNA from the 24 samples was extracted using a freeze-grind protocol, amplified, labeled with a fluorescent dye, and then hybridized to GeoChip, a functional gene array containing probes for genes involved in N, S and C cycling, metal resistance and organic contaminant degradation. Detrended correspondence analysis (DCA) of all genes detected was performed to analyze microbial community patterns. The first two axes accounted for 23.5percent of the total variation. The samples fell into two major groups: fertilized and non-fertilized, suggesting that nitrogenous fertilizer had a significant impact on soil microbial community structure and diversity. The functional gene numbers detected in fertilized samples was less that detected in non-fertilizer samples. Functional genes involving in the N cycling were mainly discussed.
Book Synopsis Nitrogen Deposition and Its Effects on the Soils, Vegetation, and Fire Risk in Southern California Deserts by : Leela Ellen Rao
Download or read book Nitrogen Deposition and Its Effects on the Soils, Vegetation, and Fire Risk in Southern California Deserts written by Leela Ellen Rao and published by . This book was released on 2008 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Methods of Soil Enzymology by : Richard P. Dick
Download or read book Methods of Soil Enzymology written by Richard P. Dick and published by John Wiley & Sons. This book was released on 2020-01-22 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: Methods of Soil Enzymology provides the first comprehensive set of vetted methods for studying enzymes in soils. Readers will especially benefit from the step-by-step explanation of the lab procedures, as well as background information for using these methods effectively and analyzing data. Main topics include activity assays, enzyme extraction, and synthetic enzyme complexes. Each method covered includes background informaton, step-by-step descriptions of the procedure, and special comments regarding nuances, pitfalls, and interpretation of the method. Learn the latest research methods, including enzyme extraction methods and procedures for creating synthetic enzyme complexes, as well as the newest ways to use small-scale and high-throughput methods for enzyme activity assays. Written for the researcher, but welcoming to those new to soil enzymology, the introduction includes conceptual information to orient those who are not familiar with these methods but want to use them. In the tradition of SSSA methods books, Methods of Soil Enzymology features a comprehensive approach with a focus on ease of use.
Book Synopsis Plant Response to Stress by : John D. Tenhunen
Download or read book Plant Response to Stress written by John D. Tenhunen and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 650 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is dedicated to international cooperation, understanding and peace. It is the end result of several years of cooperative work between scientists of three countries: the United States, Germany, and Portugal. The work presented, however, draws from a much broader base, hopefully achieving the objective of NATO Advanced Research Workshops, which have been established to allow and stimulate the exchange of new ideas and the synthesis of information by scientists of NATO countries. The tasks of the workshop were several; to review established methodologies that have provided insight into ecosystem function and adaptations of plants in mediterranean climate zones; to examine new methodologies that have recently been applied in ecological studies and have provided new types of information; to summarize recent studies in mediterranean regions of plant water relations, photosynthesis and production, mineral nutrition, plant growth and development, and response to fire; to stimulate in particular an exchange of information among scientists of European Mediterranean countries; and to discuss means by which all of these objectives might be even more effectively achieved in the future through cooperative international research efforts. This variety of themes is clearly evident in the layout of the book. Held in Sesimbra, Portugal in October of 1985, the workshop took place in a ..
Book Synopsis Investigating Feedbacks from Soil Trace Gas Fluxes of Carbon Dioxide and Nitrogen Oxides to Anthropogenic Nitrogen Deposition and Climate Change by : Jennifer Rae Eberwein
Download or read book Investigating Feedbacks from Soil Trace Gas Fluxes of Carbon Dioxide and Nitrogen Oxides to Anthropogenic Nitrogen Deposition and Climate Change written by Jennifer Rae Eberwein and published by . This book was released on 2016 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: Human alteration of the carbon (C) and nitrogen (N) cycles is having profound detrimental impacts on natural systems. This dissertation research focused on investigating soil feedbacks to multiple anthropogenic drivers to explore unifying mechanisms applicable to global biogeochemical modeling. In Chapter 1 and 2, I investigate how changes in C, N, and temperature regulate soil CO2 production (Rsoil) through changes to the Michaelis-Menten parameters (i.e. Vmax and kM) using soils from three contrasting ecosystems in southern California in Chapter 1 and in subtropical evergreen forests of southern China in Chapter 2. Overall, the response of Rsoil to N addition was generally dependent on C:N stoichiometry, consistent with predictions from the dynamic microbial carbon-use efficiency hypothesis. Furthermore, I show the first empirical results from whole soil measurements demonstrating temperature sensitivity of both Vmax and kM, showing strong support for substrate regulation of Rsoil temperature sensitivity across diverse soils. Results from Chapters 1 and 2 demonstrate great potential for Michaelis-Menten kinetics in describing Rsoil responses to N and temperature, with implications for understanding microbial physiology and broad applicability to global biogeochemical modeling. Chapter 3 extends this research by exploring N trace gas emissions and evaluating variation in the microbial community composition along an N deposition gradient in the Colorado Desert. Results from Chapter 3 present soil N fluxes that were considerably higher than expected, demonstrating a need for greater appreciation of arid systems in global N budgets. While short term effects of experimental N addition resulted in inconsistent responses in the microbial community composition, long-term N deposition resulted in a distinct differentiation of the microbial community, with possible implications for N cycling. Microbial communities associated with nitrification, identified from 16S rRNA sequencing and qPCR of amoA, demonstrate a shift from archaeal dominance at the low deposition site to more bacterial dominance at the high deposition site. Overall, results from this dissertation contribute to mechanistic understanding of soil feedbacks to climate change and nitrogen deposition, which is necessary for predicting future changes and developing strategies for mitigation of anthropogenic global change drivers.
Book Synopsis Chronic Nitrogen and Nutrient Deposition Impacts on Community Structure and Abundance of Bacteria, Fungi, and CH4 Cycling Prokaryotes in a Northern Peat Bog by : Galen Guo
Download or read book Chronic Nitrogen and Nutrient Deposition Impacts on Community Structure and Abundance of Bacteria, Fungi, and CH4 Cycling Prokaryotes in a Northern Peat Bog written by Galen Guo and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Anthropogenic nitrogen (N) deposition may threaten peatland carbon storage capabilities. Increased deposition has been linked to subsequent plant community shifts and increased decomposition rates, potentially via the disruption of natural microbial communities. By examining peat soils from randomized, replicated treatment plots in a long-term simulated chronic N deposition experiment at the Mer Bleue Bog in Eastern Ontario, Canada, my objective was to characterize how increased deposition impacts community structure and abundance of broad groups of microbial communities, and specific CH4 cycling prokaryotes. Using fingerprinting approaches and qPCR of SSU rRNA and other functional genes, my data show that with increasing nutrient loading the bacterial and fungal community structure changed. Along the same gradient methanogen abundance decreased, however there were no corresponding changes in methanotroph community structure or abundance. My results provide new insights on the possible causes of higher CO2 and CH4 effluxes seen in situ following chronic nutrient loading.
Book Synopsis Effects of Carbon Sources and Chronic Nitrogen Inputs on Microbial Abundance and Extracellular Enzyme Activity in Semi-arid Shrubland Soils by : Jorge Pastrana
Download or read book Effects of Carbon Sources and Chronic Nitrogen Inputs on Microbial Abundance and Extracellular Enzyme Activity in Semi-arid Shrubland Soils written by Jorge Pastrana and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil microbes are key players in the nutrient cycling process and acquisition by plants in terrestrial ecosystems. Changes in N availability and C source as result of human inputs, and changes in vegetation type because of invasive species, have altered the microbial community composition and function in the soil. This study examined the affects that both chronic N inputs and different C sources had on microbial abundance and enzyme activity during the spring and fall seasons in semi-arid shrubland soils. Through the use of 16S sequencing and extracellular enzyme assays, we were able to find results that contradict previous studies on N amendments and various C sources alone. Rather than favoring nutrient rich environments, copiotrophic bacterial taxa favored soils without N additions and lignin as the C source, while oligotrophic taxa favored N amended soils. Although there were no significant effects on all phyla, Actinobacteria, Firmicutes, and Proteobacteria, had the greatest changes in abundance and composition as a result of the N and C additions. Enzyme activity also has some conflicting results to previous studies. There were no changes in peroxidase or phosphatase activity across the groups and N-acetyl glucosaminidase activity tended to increase in soils with N and the addition of a C source. However, beta-glucosidase activity was highest in soils with lignin, despite being an enzyme that breaks down labile C sources such as glucose. Certain levels of N additions and C sources have had consistent effects on microbial abundance and activity across different soils, however when combining them together, some combinations differ from what has been previously observed. The results gained from this study are important because they provide some useful insight and decrease the knowledge gaps about N and C interactions, since there have been relatively few studies that examine these combined effects. By better understanding these effects, soil quality and function can be maintained as the environment changes due to human alterations.
