8,006 research outputs found
Fine-resolution global maps of root biomass carbon colonized by arbuscular and ectomycorrhizal fungi
No full textDespite the recognized importance of mycorrhizal associations in ecosystem functioning, the actual abundance patterns of mycorrhizal fungi belowground are still unknown. This information is key for better quantification of mycorrhizal impacts on ecosystem processes and for incorporating mycorrhizal pathways into global biogeochemical models. Here we present the first high-resolution maps of fine root stocks colonized by arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) fungi (MgC ha−1). The maps were assembled by combining multiple open-source databases holding information on root biomass carbon, the proportion of AM and EcM tree biomass, plot-level relative abundance of plant species and intensity of AM and EcM root colonization. We calculated root-associated AM and EcM abundance in 881 spatial units, defined as the combination of ecoregions and land cover types across six continents. The highest AM abundances are observed in the (sub-)tropics, while the highest EcM abundances occur in the taiga regions. These maps serve as a basis for future research where continuous spatial estimates of root mycorrhizal stocks are needed
Peter M. Mach
No full textabstract: Peter was 12 years old when he heard gunshots and bombing at his village.
“Lost Boys Found” is an ongoing, interdisciplinary project that is collecting, recording and archiving the oral histories of the Lost Boys/Girls of Sudan. The collection is a work-in-progress, seeking to record the oral history of as many Lost Boys/Girls as are willing, and will be used in a future book.Age: 28Region: Upper NileThis picture and bio was donated to the Lost Boys Found project from The Arizona Lost Boys Cente
Joseph Bimeler letter to Peter Kaufmann, June 8, 1844
No full textLetter from J. M. Bimeler (by Christian Weibel) to Peter Kaufmann, acknowledging receipt of Bibles and spelling books and ordering more Bibles. He repeats his statement from his letter of April 31, 1844, of a preference for Bibles that embrace the Apocrypha. The letter also requests a catalog of books on hand at Kaufmann's establishment.
Led by Joseph Bimeler (sometimes spelled Bäumeler) in 1817, a group of Lutheran separatists left Germany and eventually established the small community of Zoar in Tuscarawas County, Ohio. The group formed the Society of Separatists of Zoar, in which each person donated his or her property to the community as a whole, and in exchange for their work, the society would provide for them. After decades of economic prosperity, the unity of the village declined, and by 1898 the Zoarites disbanded the society.
Peter Kaufmann was a German immigrant and intellectual. He arrived first in Philadelphia, Pennsylvania, in 1820; in 1826 he became professor of languages at the Harmony Society town of Economy, Pennsylvania. In 1827, Kaufmann led the establishment of Teutonia, a utopian community in Columbiana County, Ohio, and published its weekly titled "Teutonia: The Herald of a Better Time." Following this he moved to Canton, Ohio, where he became translator and editor of "Der Vaterlandsfreund und Geist der Zeit" under Solomon Sala. Additionally, Kaufmann wrote a number of books on education, as well as a German almanac. He was also an influential Democrat, counting President Van Buren among his friends, and knew Ralph Waldo Emerson
Mycorrhizal tree impacts on topsoil biogeochemical properties in tropical forests
No full textIn tropical regions, the patterns of carbon (C) and nutrient properties among ecosystems dominated by distinct mycorrhizal associations are unknown. We aim to reveal whether the dynamics differ and the ecological drivers and ecosystem functioning implications of such differences. Based on a dataset of 97 tropical forest sites, we related EcM trees abundance (as a proxy for the transition from AM to EcM trees dominance) to different topsoil properties, climatic conditions and microbial abundance proxies through Generalized Additive Models. Higher abundances of EcM trees were correlated with higher topsoil concentrations of total nitrogen and C, extractable phosphorus and potassium, delta C-13, mean annual temperature, precipitation, microbial (bacterial and fungal) biomass and the relative abundance of saprotrophic fungi. Synthesis. Our results reveal consistent differences in carbon and nutrient content between arbuscular mycorrhizal (AM-) and EcM-dominated vegetation across the tropical biome, pointing to lower soil fertility and lower rates of C and nutrient transformation processes in EcM-dominated forests. These patterns associate with lower topsoil C accumulation when compared to AM vegetation, which contrasts with patterns reported for temperate forests. We suggest that different mechanisms of soil organic matter accumulation explain the contrasting impacts of EcM dominance on topsoil properties of temperate and tropical biomes. Global vegetation and C models should account for the contrasting impacts of distinct mycorrhizal vegetation in different climatic zones.Environmental Biolog
Implementation of mycorrhizal mechanisms into soil carbon model improves the prediction of long-term processes of plant litter decomposition
No full textEnvironmental Biolog
Invasive species’ leaf traits and dissimilarity from natives shape their impact on nitrogen cycling: A meta‐analysis
No full textMany exotic species have little apparent impact on ecosystem processes, whereas others have dramatic consequences for human and ecosystem health. There is growing evidence that invasions foster eutrophication. We need to identify species that are harmful and systems that are vulnerable to anticipate these consequences. Species’ traits may provide the necessary insights.
We conducted a global meta-analysis to determine whether plant leaf and litter functional traits, and particularly leaf and litter nitrogen (N) content and carbon: nitrogen (C : N) ratio, explain variation in invasive species’ impacts on soil N cycling.
Dissimilarity in leaf and litter traits among invaded and noninvaded plant communities control the magnitude and direction of invasion impacts on N cycling. Invasions that caused the greatest increases in soil inorganic N and mineralization rates had a much greater litter N content and lower litter C : N in the invaded than the reference community. Trait dissimilarities were better predictors than the trait values of invasive species alone.
Quantifying baseline community tissue traits, in addition to those of the invasive species, is critical to understanding the impacts of invasion on soil N cycling.Lee, Marissa R; Bernhardt, Emily S; Bodegom, Peter M; Cornelissen, J. Hans C; Kattge, Jens; Laughlin, Daniel C; Niinemets, Ülo; Peñuelas, Josep; Reich, Peter B; Yguel, Benjamin; Wright, Justin P. (2017). Invasive species’ leaf traits and dissimilarity from natives shape their impact on nitrogen cycling: A meta‐analysis. Retrieved from the University Digital Conservancy, 10.1111/nph.14115
Peter Logan: Victorian Fetishism [Audio interview]
No full textPeter Logan is the author of Nerves and Narratives: A Cultural History of Hysteria in Nineteenth-Century British Prose (1997) and, more recently, Victorian Fetishism: Intellectuals and Primitives (2009). On May 15, 2012, Fred Rowland interviewed Peter Logan to discuss Victorian Fetishism, which details the development of ideas about the primitive and how these concepts set the boundaries of culture in Victorian Britain. Drawing from Lucretius, Vico, and Auguste Comte, Peter Logan explains how fetishism – the defining feature of culture’s absence – figured in the works of literary and cultural critic Matthew Arnold, realist novelist George Eliot, and anthropologist Edward Tylor.Temple University. College of Liberal ArtsTemple University. LibrariesEnglishLearning and Research ServicesAudacityAudacit
Der Wahrheitssucher : su Peter Weiss, Dante e l’utopia
No full textThe contribution outlines the utopian dimension of the work and aesthetics of the German-Jewish-Swedish author Peter Weiss (1916-1982), focusing mainly on his "DC-Projekt", the plan of a political rewriting of Dantes' Divine Comedy for the modern stage (1960s). The contribution contends that the medieval poet, called "the truthsearcher" in the posthumous drama "Inferno", is the key figure of the author's utopian concern in his lifelong alternation of autobiographical, poetical and political issues
Linking Land Use and Plant Functional Diversity Patterns in Sabah, Borneo, through Large-Scale Spatially Continuous Sentinel-2 Inference
No full textGlobal biodiversity losses erode the functioning of our vital ecosystems. Functional diversity is increasingly recognized as a critical link between biodiversity and ecosystem functioning. Satellite earth observation was proposed to address the current absence of information on large-scale continuous patterns of plant functional diversity. This study demonstrates the inference and spatial mapping of functional diversity metrics through satellite remote sensing over a large key biodiversity region (Sabah, Malaysian Borneo, ~53,000 km2) and compares the derived estimates across a land-use gradient as an initial qualitative assessment to test the potential merits of the approach. Functional traits (leaf water content, chlorophyll-a and -b, and leaf area index) were estimated from Sentinel-2 spectral reflectance using a pre-trained neural network on radiative transfer modeling simulations. Multivariate functional diversity metrics were calculated, including functional richness, divergence, and evenness. Spatial patterns of functional diversity were related to land-use data distinguishing intact forest, logged forest, and oil palm plantations. Spatial patterns of satellite remotely sensed functional diversity are significantly related to differences in land use. Intact forests, as well as logged forests, featured consistently higher functional diversity compared to oil palm plantations. Differences were profound for functional divergence, whereas functional richness exhibited relatively large variances within land-use classes. By linking large-scale patterns of functional diversity as derived from satellite remote sensing to land-use information, this study indicated initial responsiveness to broad human disturbance gradients over large geographical and spatially contiguous extents. Despite uncertainties about the accuracy of the spatial patterns, this study provides a coherent early application of satellite-derived functional diversity toward further validation of its responsiveness across ecological gradients
The imprint of plants on ecosystem functioning: A data-driven approach
No full textTerrestrial ecosystems strongly determine the exchange of carbon, water and energy between the biosphere and atmosphere. These exchanges are influenced by environmental conditions (e.g., local meteorology, soils), but generally mediated by organisms. Often, mathematical descriptions of these processes are implemented in terrestrial biosphere models. Model implementations of this kind should be evaluated by empirical analyses of relationships between observed patterns of ecosystem functioning, vegetation structure, plant traits, and environmental conditions. However, the question of how to describe the imprint of plants on ecosystem functioning based on observations has not yet been systematically investigated. One approach might be to identify and quantify functional attributes or responsiveness of ecosystems (often very short-term in nature) that contribute to the long-term (i.e., annual but also seasonal or daily) metrics commonly in use. Here we define these patterns as “ecosystem functional properties”, or EFPs. Such as the ecosystem capacity of carbon assimilation or the maximum light use efficiency of an ecosystem. While EFPs should be directly derivable from flux measurements at the ecosystem level, we posit that these inherently include the influence of specific plant traits and their local heterogeneity. We present different options of upscaling in situ measured plant traits to the ecosystem level (ecosystem vegetation properties – EVPs) and provide examples of empirical analyses on plants’ imprint on ecosystem functioning by combining in situ measured plant traits and ecosystem flux measurements. Finally, we discuss how recent advances in remote sensing contribute to this framework.Musavi, Talie; Mahecha, Miguel D; Migliavacca, Mirco; Reichstein, Markus; van de Weg, Martine Janet; van Bodegom, Peter M; Bahn, Michael; Wirth, Christian; Reich, Peter B; Schrodt, Franziska; Kattge, Jens. (2015). The imprint of plants on ecosystem functioning: A data-driven approach. Retrieved from the University Digital Conservancy, 10.1016/j.jag.2015.05.009
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