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Author : Roberts Nowak
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (316 download)
Download or read book Effects of Elevated CO2 on Root Dynamics and Root Function in a Mojave Desert Ecosystem written by Roberts Nowak and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :
Publisher :
ISBN 13 :
Total Pages : 26 pages
Book Rating : 4.:/5 (727 download)
Download or read book EFFECTS OF ELEVATED CO2 ON ROOT FUNCTION AND SOIL RESPIRATION IN A MOJAVE DESERT ECOSYSTEM. written by and published by . This book was released on 2007 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increases in atmospheric CO2 concentration during the last 250 years are unequivocal, and CO2 will continue to increase at least for the next several decades (Houghton et al. 2001, Keeling & Whorf 2002). Arid ecosystems are some of the most important biomes globally on a land surface area basis, are increasing in area at an alarming pace (Dregne 1991), and have a strong coupling with regional climate (Asner & Heidebrecht 2005). These water-limited ecosystems also are predicted to be the most sensitive to elevated CO2, in part because they are stressful environments where plant responses to elevated CO2 may be amplified (Strain & Bazzaz 1983). Indeed, all C3 species examined at the Nevada Desert FACE Facility (NDFF) have shown increased A{sub net} under elevated CO2 (Ellsworth et al. 2004, Naumburg et al. 2003, Nowak et al. 2004). Furthermore, increased shoot growth for individual species under elevated CO2 was spectacular in a very wet year (Smith et al. 2000), although the response in low to average precipitation years has been smaller (Housman et al. 2006). Increases in perennial cover and biomass at the NDFF are consistent with long term trends in the Mojave Desert and elsewhere in the Southwest, indicating C sequestration in woody biomass (Potter et al. 2006). Elevated CO2 also increases belowground net primary production (BNPP), with average increases of 70%, 21%, and 11% for forests, bogs, and grasslands, respectively (Nowak et al. 2004). Although detailed studies of elevated CO2 responses for desert root systems were virtually non-existent prior to our research, we anticipated that C sequestration may occur by desert root systems for several reasons. First, desert ecosystems exhibit increases in net photosynthesis and primary production at elevated CO2. If large quantities of root litter enter the ecosystem at a time when most decomposers are inactive, significant quantities of carbon may be stored belowground in relatively recalcitrant forms. Indeed, a model-based analysis predicted that the arid/semiarid southwestern bioclimatic region had one of the highest rates of net carbon storage in the United States over the past century (Schimel et al. 2000). Second, root systems of desert plants are often extensive (Foxx et al. 1984, Hartle et al. 2006) with relatively large proportions of roots deep in the soil (Schenk & Jackson 2002). Thus, an understanding of belowground processes in desert ecosystems provides information on the potential for terrestrial carbon sequestration in desert ecosystems.
Author : David Charles Housman
Publisher :
ISBN 13 :
Total Pages : 212 pages
Book Rating : 4.:/5 (53 download)
Download or read book Effects of Elevated CO2 on Primary Productivity in a Mojave Desert Ecosystem written by David Charles Housman and published by . This book was released on 2002 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Daniel Benjamin Stover
Publisher :
ISBN 13 :
Total Pages : 250 pages
Book Rating : 4.:/5 (175 download)
Download or read book Effects of Elevated Atmospheric CO2 on Root Dynamics, Biomass and Architecture in a Scrub-oak Ecosystem at Kennedy Space Center, Florida written by Daniel Benjamin Stover and published by . This book was released on 2007 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : P. S. Curtis
Publisher : Springer Science & Business Media
ISBN 13 : 9401708517
Total Pages : 379 pages
Book Rating : 4.4/5 (17 download)
Download or read book Belowground Responses to Rising Atmospheric CO2: Implications for Plants, Soil Biota, and Ecosystem Processes written by P. S. Curtis and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 379 pages. Available in PDF, EPUB and Kindle. Book excerpt: As atmospheric CO2 increases there will almost certainly be alterations in soil carbon fluxes. It is likely that such alterations will be accompanied by changes in the partitioning of carbon between organic structures and to soil processes. These changes have the potential for further altering the structure and function of terrestrial ecosystems. While there has been increasing recognition of the importance of soil-mediated responses to global climate change, the nature and magnitude of these responses are not well understood. In an effort to expand our assessment of the significance of belowground responses to rising atmospheric CO2, a workshop has been organized that resulted in the peer-reviewed contributions that are contained in this volume.
Author : John Joseph DiLustro
Publisher :
ISBN 13 :
Total Pages : 176 pages
Book Rating : 4.:/5 (485 download)
Download or read book Effects of Elevated Atmospheric CO2 on Root Growth, Turnover and Decomposition in a Scrub Oak Ecosystem written by John Joseph DiLustro and published by . This book was released on 2000 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Ecological Society of America. Meeting
Publisher :
ISBN 13 :
Total Pages : 788 pages
Book Rating : 4.F/5 ( download)
Download or read book Ecological Society of America ... Annual Meeting Abstracts written by Ecological Society of America. Meeting and published by . This book was released on 2005 with total page 788 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :
Publisher :
ISBN 13 :
Total Pages : 298 pages
Book Rating : 4.:/5 (57 download)
Download or read book Effects of Elevated Atmospheric Carbon Dioxide on the Arbuscular-mycorrhizal Symbiosis at the Host Plant, Plant Community, and Ecosystem Level written by and published by . This book was released on 1997 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Edward Primka
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (13 download)
Download or read book Fine Root Dynamics and Their Effect on Soil CO2 Efflux Across a Forested Landscape with Complex Topography written by Edward Primka and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Many studies and experiments have attempted to quantify the role of soil CO2 efflux in temperate forests. These efforts include estimated contribution of roots to soil CO2 efflux that vary widely and in many ways, leaving more questions than answers. From previous studies, it is known that fine root dynamics, soil water, and soil temperature all can impact soil CO2 efflux rates. This begs the question: how much can soil CO2 efflux be explained by fine root dynamics independent of soil water and temperature fluctuation? Fine root dynamics have often been studied where soil water and nutrient conditions were relatively homogenous across space to allow for manipulation of these soil conditions. Complex topography (e.g., hillslopes) structures the amount of soil water and litter distribution over time and is a common aspect of many forested landscapes. No studies to my knowledge have examined the effect of spatially structured soil water conditions on fine root dynamics. Manipulation studies and field studies of relatively homogenous areas have shown that fine root dynamics may show non-linear trends with increasing soil water content over short periods of time. Specifically, fine root production and lifespan tend to increase, while fine root mortality tends to decrease with increasing soil water content. Studies have also shown that under excessive soil water conditions fine root lifespan and production tend to decrease, while fine root mortality increases. This led me to the question: do these non-linear trends in fine root dynamics hold across spatial soil water gradients in forested catchments? In chapter two, I examined the effect of complex topography on fine root lifespan. I found a wet-dry split in survivorship with roots living for a longer period of time in wetter areas of the landscape. Within chapter three, I studied the effects of hillslope on fine root dynamics, specifically fine root production, mortality, standing crop, and turnover. Here I found two distinct strategies based on spatially structured soil water content. In dry soils, I found that roots favored a strategy of temporal avoidance of harsh conditions, such that there was high root turnover in these areas. In wet regions, roots favored a strategy of subsistence by simply living through harsh or unfavorable conditions, shown via decreased fine root turnover. Additionally, annual precipitation conditions created a temporal gradient in soil moisture conditions over the course of my study. The temporal soil moisture gradient resulted in some of the non-linear relationships between fine root dynamics and water content that I had anticipated. In chapter four, I examined the effects of fine root dynamics on soil CO2 efflux rates. I found that fine root mortality and soil CO2 efflux were only positively correlated at warm temperatures. Additionally, I found a significant effect of proportion of new fine roots on soil CO2 efflux. Across these three chapters, I showed different adaptive fine root strategies employed by roots depending upon where they were established in the landscape. Specifically, I found a strategy of temporal avoidance in dry regions and subsistence in wet regions, instead of soil moisture threshold effects due to spatially structured soil water content. Additionally, I showed that fine root dynamics influenced soil CO2 efflux via proportion of new roots and the interaction between fine root mortality and soil temperature. The complexity of the interactions between fine root dynamics and abiotic conditions may explain why there was such a large range in estimated contribution of fine root respiration through various processes to soil CO2 efflux. Understanding how spatial water gradients impact fine root dynamics and the effect of differences in fine root dynamics on rates of soil CO2 efflux brings some clarity as to why such large estimations of fine root dynamic contributions to soil CO2 efflux exist.
Author : Linh M. P. Nguyen
Publisher :
ISBN 13 :
Total Pages : 148 pages
Book Rating : 4.:/5 (426 download)
Download or read book Effects of Elevated CO2 on Soil Microbial Communities of the Mojave Desert written by Linh M. P. Nguyen and published by . This book was released on 2008 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Carmody K. McCalley
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (654 download)
Download or read book Sources and Controls of Reactive Nitrogen Gas Emissions from a Mojave Desert Ecosystem written by Carmody K. McCalley and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This body of work considerably expands our understanding of gaseous nitrogen (N) loss dynamics in arid ecosystems, a process that directly affects longterm N bioavailability and the release of chemically important gas species into the atmosphere. Chapter one focuses on identifying controls over biological sources of reactive N gas emissions, especially the pulse of NO and NH3 that occurs following precipitation. This research shows a two-step response of reactive N gas emissions to pulsed water additions. First, there is a large transient NH3 pulse. Second, biological activity is stimulated leading to NO production by nitrifying bacteria. Results indicate that biological sources of NO and NH3 efflux respond primarily to the addition of water; however, fluxes are modulated by temperature and nutrient constraints on microbial activity. Chapter two explores the role of non-biological processes in reactive N gas emissions from desert soils. Combination of laboratory and field measurements show that abiotic reactions are a key component of N loss from desert soils, both under dry conditions and during post-wetting periods. It is hypothesized that during the summer, extreme surface soil temperatures caused by direct exposure to incoming solar radiation result in thermal decomposition of N-containing compounds, yielding elevated rates of reactive N gas efflux. Chapter three focuses on the effects of elevated CO2 on soil fluxes of reactive N gases. Under soil conditions optimal for biological activity, long-term fumigation with elevated CO2 reduces reactive N gas losses in the islands of fertility created by the dominant shrub Larea tridentata. These results provide supporting evidence that elevated CO2 alters soil N dynamics in arid ecosystems, including increased N immobilization and decreased N mineralization and nitrification. Chapter four provides a robust estimate of annual reactive N gas emissions for a Mojave Desert ecosystem, accounting for daily, seasonal and yearly variation in environmental conditions. This annual estimate of 0.1 to 0.6 kg N ha-1 y-1 includes considerable variation, reflecting inter-annual variability in summer precipitation and growing season moisture conditions. These results demonstrate the strong impact that alterations in precipitation patterns under future climate scenarios will have on N dynamics in water limited ecosystems.
Author : Vasiliki Balogianni
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (13 download)
Download or read book Root Dynamics, Management Effects and Carbon Sequestration on Invaded and Native Semi-Arid Grasslands written by Vasiliki Balogianni and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (135 download)
Download or read book Root Growth and Function in Elevated CO2 written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Walter G. Whitford
Publisher : Academic Press
ISBN 13 : 0081026552
Total Pages : 473 pages
Book Rating : 4.0/5 (81 download)
Download or read book Ecology of Desert Systems written by Walter G. Whitford and published by Academic Press. This book was released on 2019-08-20 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nearly one-third of the land area on our planet is classified as arid or desert. Therefore, an understanding of the dynamics of such arid ecosystems is essential to managing those systems in a way that sustains human populations. This second edition of Ecology of Desert Systems provides a clear, extensive guide to the complex interactions involved in these areas. This book details the relationships between abiotic and biotic environments of desert ecosystems, demonstrating to readers how these interactions drive ecological processes. These include plant growth and animal reproductive success, the spatial and temporal distribution of vegetation and animals, and the influence of invasive species and anthropogenic climate change specific to arid systems. Drawing on the extensive experience of its expert authors, Ecology of Desert Systems is an essential guide to arid ecosystems for students looking for an overview of the field, researchers keen to learn how their work fits in to the overall picture, and those involved with environmental management of desert areas. Highlights the complexity of global desert systems in a clear, concise way Reviews the most current issues facing researchers in the field, including the spread of invasive species due to globalized trade, the impact of industrial mining, and climate change Updated and extended to include information on invasive species management, industrial mining impacts, and the current and future role of climate change in desert systems
Author : Petra Marschner
Publisher : Springer Science & Business Media
ISBN 13 : 3540680276
Total Pages : 409 pages
Book Rating : 4.5/5 (46 download)
Download or read book Nutrient Cycling in Terrestrial Ecosystems written by Petra Marschner and published by Springer Science & Business Media. This book was released on 2007-05-01 with total page 409 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a comprehensive overview of nutrient cycling processes and their importance for plant growth and ecosystem sustainability. The book combines fundamental scientific studies and devised practical approaches. It contains contributions of leading international authorities from various disciplines resulting in multidisciplinary approaches, and all chapters have been carefully reviewed. This volume will support scientists and practitioners alike.
Author : Amanda Cantu Swanson
Publisher :
ISBN 13 : 9780355471991
Total Pages : 133 pages
Book Rating : 4.4/5 (719 download)
Download or read book Disturbance, Restoration, and Soil Carbon Dynamics in Desert and Tropical Ecosystems written by Amanda Cantu Swanson and published by . This book was released on 2017 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: Disturbances, natural or anthropogenic, alter ecosystem functioning by changing the biotic composition, biogeochemical cycling, or the physical structure of an environment. As carbon dioxide is a major contributor to global climate change, disturbances to different components of the carbon (C) cycle may further affect atmospheric CO2 concentrations. Soils store vast amounts of C and have the potential to sequester or release CO2. Two of the most extreme ecosystems, deserts and tropical forests, play an important role in the global C cycle, storing C in soils and vegetative biomass. The overarching objective of this dissertation is to quantify changes in soil C cycling after a disturbance in desert and tropical ecosystems. My first chapter addressed how soil inorganic C cycling changes with vegetation removal in a Colorado desert ecosystem. Through manipulative field and lab experiments, I explored changes in C pools after vegetation removal by measuring changes in the isotopic composition of C pools and effluxed CO2. I found that there were significant changes in C cycling after the vegetation was removed; there were fewer newer C inputs and that a greater proportion of CO2 comes soil inorganic C in unvegetated soils. For my second chapter, I looked at soil C recovery with revegetation of Larrea tridentata, finding that there was some recovery of the water extractable organic and microbial biomass C pools. Although the isotopic composition of soil carbon pools did not change with restoration, I also found some seasonal patterns such that changes in soil C pools may have been linked to timing of shrub and microbial activity. My third chapter addressed spatial differences in root and hyphal dynamics and production associated with soil disturbances created by leaf cutter ants (LCA). I collected continuous soil data and automated minirhizotron images to assess belowground dynamics, finding that LCA altered their soil environment and increase root and hyphal production in LCA nests. Overall, my dissertation work demonstrates that disturbances impact various components of the C cycle and that changes to C cycling processes may change how relevant those processes are at different temporal and spatial scales.
Author :
Publisher :
ISBN 13 :
Total Pages : 142 pages
Book Rating : 4.:/5 (441 download)
Download or read book Forest Responses to Rising Atmospheric CO2 written by and published by . This book was released on 2008 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increased forest growth in response to rising atmospheric concentrations of CO2 may mitigate a portion of fossil fuel emissions, especially if carbon is sequestered in longlived biomass or soil pools. Greater carbon uptake under elevated atmospheric [CO2] in forested ecosystems may facilitate the production of small diameter (i.e. "fine") roots used for nutrient acquisition. Increased fine-root production in forested ecosystems may affect soil carbon storage and nitrogen cycling because fine roots live and die in the span of a year. My dissertation research took advantage of a long-term, on-going Free-Air CO2-Enrichment experiment in a sweetgum (Liquidambar styraciflua L.) forest stand at Oak Ridge National Laboratory to investigate the causes and consequences of increased fine-root production under elevated [CO2]. To examine the premise that N limitation was the cause of increased fine-root production in the CO2-enriched sweetgum stand, I fertilized plots in an adjacent sweetgum plantation with 200 kg ha−1 of N as urea. The relative C flux to wood production that I observed in the fertilized treatment is consistent with the premise that increased root production in the adjacent FACE experiment is in response to N limitation. To examine the consequences of increased fine-root production under elevated [CO2], I: (1) quantified fine-root biomass and N inputs at several soil depths using a long-term minirhizotron data set combined with continuous, root-specific measurements of root mass per unit length and [N], and (2) allowed fine roots grown under current and elevated [CO2] to decompose in a common garden experiment by modifying existing litterbag methodology. I found that C and N inputs via root mortality were doubled under elevated [CO2], and half of the inputs were below 30 cm soil depth. However, CO2-enrichment had no effect on fine-root chemistry or decomposition rate, and therefore more root detritus may be incorporated into long-lived soil organic matter under elevated [CO2]. Quantification of the effects of elevated CO2 on the fate of a greater quantity of fine-root detritus, especially at depth in the soil, will provide critical information needed for predicting processes such as long-term soil C storage and N cycling in response to environmental change.
