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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
301

Species Richness of Soil and Leaf Litter Tardigrades in the Great Smoky Mountains National Park (North Carolina/Tennessee, USA)

Nelson, Diane R., Bartels, Paul J. 02 August 2013 (has links)
A large database now exists for tardigrades in the Great Smoky Mountains National Park (GSMNP) consisting of 780 samples, 15,618 specimens, and 80 species including 14 new to science. We found 43 species of tardigrades in 150 soil/leaf litter samples. We calculated the Chao 1 species richness estimate with the species accumulation curve for the GSMNP and confirmed that our species list is virtually complete. Compared with soil data from mt. Fuji, Japan, estimated species richness in GSMNP was significantly higher. In our comparison of previous studies of soil/leaf litter tardigrades in other geographic areas, only the Kanagawa prefecture of Japan reported a higher number of species (47) than the GSMNP. Species richness estimators are valuable tools for comparing diversity in different habitats, even when sampling effort varies between studies.
302

The handling of undated pig embryos and foetuses as a prelude to histological studies of morphogenesis in the oral region

van Rensburg, Barend. Gabriel January 1976 (has links)
Magister Chirurgiae Dentium (MChD) / The author is interested in the morphogenesis of the oral region including the nasopalatine complex. With the intention of undertaking a study of the· embryological development in this area, perusal of available literature failed to reveal a single compreh.ensive description of the reception and handling of embryonic and foetal material, mensuration and preparation for miscroscopy. Human material for embryological study is relatively scarce in· the Republic of South Africa. According to the literature there is, however, a distinct similarity between human and domestic pig development in certain regions, notably the palate. Furthermore, pig embryos and foetuses are available in comparative abundance from sows slaughtered at abattoirs. As a consequence of the above-mentioned factors it was,decided to undertake a -preparatory study in order to firstly evaluate existing methods of handling of embryonic and foetal material and secondly, to statistically evaluate data relating to mass and measurements.'· The aim was to draw a comparison with existing information and to select a sample for investigation. Embryos and foetuses were removed from slaughtered sows in a fresh state and removed to the laboratory immersed in 10 per cent neutral buffered formol saline. In the laboratory foetal membranes were removed, umbilical cords cut and the specimens weighed. They were then placed in Bouin's solution for final fixation and decalcification. Instruments were designed to measure crown-tailroot length, crown-rump length and dorsal profile length. After one day in Bouin's solution all specimens were measured. In order to determine the accuracy of the weighing and measuring procedures ten fixed specimens were weighed and measured on seven consecutive days. Statistical analysis of this data indicated that crown-rump length was the most accurately determinable linear measurement, judged by both the coefficient of variation and the standard deviation. On this basis crown-rump length was chosen as the criterion for selecting the sample to be studied. Correlation between linear measurements and between linear measurements and mass for the entire series showed a very strong positive relationship between all the parameters indicating that a dimensional relationship was maintained during growth. After measuring, the small specimens were embedded whole while larger embryos and foetuses were decapitated. A method was described for trimming and embedding these heads in such a way that subsequent sectioning would take place in a standardised transverse plane. In larger specimens this procedure had to be delayed until demineralization had taken place. Conclusions based on a consideration of data for the entire population included the following: 1. The mean number of specimens per litter was 6,475. 2. The number of pigs per litter stayed relatively constant throughout the period of gestation. 3. Mass showed a greater intra-litter variation than any of the three linear measurements recorded. 4. Relatively, lengths appeared to vary less in older than in younger Ldtt.ers-, irrespective of litter size
303

Changing Landscape of Food Production in Western Bhutan-Adaptation of Peasant Farmers in an Era of Organic Agriculture / ブータン西部の変わりゆく食料生産景観:有機農業時代における農民たちの対応

Kobayashi, Mai 23 March 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(地球環境学) / 甲第19877号 / 地環博第151号 / 新制||地環||30(附属図書館) / 32913 / 京都大学大学院地球環境学舎地球環境学専攻 / (主査)准教授 深町 加津枝, 教授 柴田 昌三, 教授 星野 敏 / 学位規則第4条第1項該当 / Doctor of Global Environmental Studies / Kyoto University / DFAM
304

Invasive Species Shift Fungal Driven Decomposition in Midwestern Forests

Reed, Adam M. 20 May 2020 (has links)
No description available.
305

Factors Affecting Survival and Cause-specific Mortality of Saiga Calves (Saiga tatarica mongolica) in Mongolia

Bayarbaatar, Buuveibaatar 01 January 2011 (has links) (PDF)
Factors affecting juvenile survival are poorly known in the world’s most northern antelope, the endangered saiga (Saiga tatarica), yet they are fundamental for understanding what drives population change. For saiga neonates monitored in Sharga Nature Reserve, western Mongolia, during 2008–2010, male and single calves were heavier than those of female and twins, respectively. However, there was no significant difference in seasonal and annual survival rate between male and female or singletons and twins. Litter size and birth mass varied among years, and there was a negative relationship between these variables. Multiple regression models suggest that summer precipitation in previous years and spring mean temperature explained inter-annual variations in twinning rate, and mortality was highest during summer. Covariates providing the best model fit included year, litter size, and body weight, suggesting that environmental conditions influence twinning rates and body mass may play a key role in neonate survival rate in the first year. We identified 3 sources of mortality – predation by raptors, foxes (red and corsac, Vulpes vulpes and V. corsac), and lynx (Lynx lynx). Most predation was by raptors, such as golden eagles (Aquila chrysaetos) and cinereous vulture (Aegypius monachus). Our results point to both environmental and biotic factors affecting juvenile survival.
306

Evaluating the effects of pine and miscanthus biochar on water activity and Escherichia coli populations in commercial broiler litter

Marty, Christopher Austin 10 December 2021 (has links) (PDF)
The decrease in subtherapeutic antibiotic administration in poultry has increased the need to address production challenges caused by pathogens, such as E. coli. One potential way to improve bird health and reduce bacterial infection is through the addition of litter amendments that absorb moisture. Biochar (BC) has previously been shown to increase water holding capacity in poultry litter, but its effects on E. coli mitigation are unknown. The objectives of this research were to 1) evaluate water activity of poultry litter amended with pine and miscanthus BC, and 2) determine the effects of different BC inclusion rates on litter E. coli populations. The studies found that BC increased water activity when mixed with broiler litter, and pine BC resulted in lower E. coli counts over time than miscanthus BC. An inclusion rate of 30% by weight of pine BC was most effective at reducing E. coli populations in broiler litter.
307

Biotic controls of decomposition dynamics in aquatic systems

Montemarano, Justin Joseph 26 June 2013 (has links)
No description available.
308

Physiological Variability in Juvenile Nine-Banded Armadillos: Responses to Simulated Burrow Conditions During Development

Spencer, Megan A. 17 August 2011 (has links)
No description available.
309

Environmental drivers of soil and plant microbiomes in agricultural and grassland ecosystems

Fareed Mohamed Wahdan, Sara 04 October 2021 (has links)
Soils and plant microbial communities are intricately linked to ecosystem functioning as they play important roles in nutrients dynamics as decomposers and feedback to plant communities as mutualists and pathogens. Numerous soil physicochemical factors as well as the land use management are shaping the composition and dynamics of microbial community. In addition, global warming and climate change are the most prominent of all environmental factors that influence all kinds of the living organisms including microbes associated to the plant soil systems. A better understanding of the environmental drivers shaping these microbial communities especially under future climate will help to understand and predict the expected changes of ecosystems functions and accordingly of the services they provide. In addition, such knowledge will help to detect potential ways on how soil microorganisms can be harnessed to help mitigating the negative consequences of climate change.The Global Change Experimental Facility (GCEF) is settled in the field research station of the Helmholtz Centre for Environmental Research (UFZ) in Bad Lauchstädt, Saxony-Anhalt, Germany (51_22’60 N, 11_50’60 E, 118 m a.s.l.). This facility has been designed to investigate the consequences of a predicted future climate scenario expected in 50-70 years in Central Germany on ecosystem processes under different land-use regimes applied on large field plots in comparison to similar sets of plots under the ambient climate. We performed our study using this research facility, with the aim to analyze the impact of future climate conditions, soil physicochemical factors, and/or land use type and intensity on microbial communities in different habitats (rhizosphere soil, plant endosphere, and plant residues) in grassland and cropland ecosystems. To assess the microbial communities, we used the highly sensitive and powerful highthroughput next generation sequencing, Illumina Miseq.This thesis constitutes the first assessment of microbial communities in the GCEF experimental facility. The samples were collected in 2015 for manuscript 4, while for manuscripts 1, 2, 3, 5, 6, the samples were collected in 2018-2019. Manuscript 1: (Sansupa, Wahdan, Hossen et al., 2021; Applied Science 2021, 11, 688) “Can we use functional annotation of prokaryotic taxa (FAPROTAX) to assign the ecological functions of investigated the potential use of FAPROTAX for bacterial functional annotation in non-aquatic ecosystems, specifically in soil. For this study, we used microbial datasets of soil systems including rhizosphere soil of Trifolium pratense from the extensively used meadow plots in the GCEF. We hypothesized that FAPROTAX can be used in terrestrial ecosystems. Our survey revealed that FAPROTAX tool can be used for screening or grouping of 16S derived bacterial data from terrestrial ecosystems and its performance could be enhanced through improving the taxonomic and functional reference databases. Manuscript 2: (Wahdan et al., 2021; Frontiers in Microbiology 12:629169) “Targeting the active rhizosphere microbiome of Trifolium pratense in grassland evidences a stronger-than-expected belowground biodiversity-ecosystem functioning link”. In this study, we used the bromodeoxyuridine (BrdU) immunocapture technique combined with pair-end Illumina sequencing to differentiate between total and active microbiomes (including both bacteria and fungi) in the rhizosphere of T. pratense. In the same rhizosphere soil samples, we also measured the activities of three microbial extracellular hydrolytic enzymes, (ß-glucosidase, N-acetylglucosaminidase, and acid phosphatase), which play central roles in the C, N, and P acquisition. We investigated the proportion of active and total rhizosphere microbiomes, and their responses to the manipulated future climate in the GCEF. In addition, we identified the possible links between total and active microbiomes and the soil ecosystem function (extracellular enzyme production). Our results revealed that the active microbes of the rhizosphere represented 42.8 and 32.1% of the total bacterial and fungal operational taxonomic units (OTUs), respectively. Active and total microbial fractions were taxonomically and functionally diverse and displayed different responses to variations of soil physicochemical factors. We also showed that the richness of overall and specific functional groups of active microbes in rhizosphere soil significantly correlated with the measured enzyme activities, while total microbial richness did not. Manuscript 3: (Wahdan et al., 2021; Microbiology Open 10:e1217) “Deciphering Trifolium pratense L. (red clover) holobiont reveals a resistant microbial community assembly to future climate changes predicted for the next 50–70 years”. We investigated the microbial communities of bacteria and fungi associated with four plant parts of T. pratense (the rhizosphere and the endopheres of the roots, whole shoot system (leaves and stems), and of the flower) and evaluated their potential ecological and metabolic functions in response to future climate conditions. This study was performed on the GCEF extensively managed grassland plots. Our analyses indicated that plant tissue/compartments differentiation enables the formation of a unique ecological niches that harbor specific microbial communities. Except for the fungal communities of the aboveground compartments, T. pratense microbiome diversity and community composition showed a resistance against the future climate changes. We also analyzed the predicted bacterial metabolic functional genes of red clover. Thereby, we detected microbial genes involved in plant growth processes, such as biofertilisation (nitrogen fixation, phosphorus solubilisation, and siderophore biosynthesis) and biostimulation (phytohormone and auxin production), which were not influenced by the future climate. Manuscript 4: (Wahdan et al., 2021; Environmental Microbiology) “Organic agricultural practice enhances arbuscular mycorrhizal symbiosis in correspondence to soil warming and altered precipitation patterns”. This study was performed on the conventional and organic farming plots under both ambient and future climate conditions. We evaluated the effect of climate (ambient vs. future), agricultural practice (conventional vs. organic farming) and their interaction on Arbuscular Mycorrhizal Fungi (AMF) community composition and richness inside wheat roots. In addition, we evaluated the relationship between molecular richness of indigenous root AMF and wheat yield parameters. Future climate altered the total AMF community composition and a sub-community of Glomeraceae. Further, application of different agricultural practices altered both total AMF and Glomeraceae community, whereby organic farming appeared to enhance total AMF and Diversisporaceae richness. Under the future climate scenario, organic farming enhanced total AMF and Gigasporaceae richness in comparison with conventional farming. Our results revealed a positive correlation between AMF richness and wheat nutrient contents not only in organic farming system but also under conventionally managed fields. Manuscript 5: (Wahdan et al., 2020; Microorganisms 8, 908) “Future climate significantly alters fungal plant pathogen dynamics during the early phase of wheat litter decomposition”. This study was performed on the conventional farming plots. We investigated the structure and ecological functions of fungal communities colonizing wheat during the early phase of decomposition (0, 30, and 60 days) under current and future climate conditions. We found that plant pathogenic fungi dominated (~87% of the total sequences) within the wheat residue mycobiome. Destructive wheat fungal pathogens such as Fusarium graminearum, Fusarium tricinctum, and Zymoseptoria tritci were detected under ambient and future climates. Additionally, the future climate brought new pathogens to the system. Manuscript 6: (Wahdan et al., 2021; Microbial Ecology 10.1007/s00248-021-01840-6) “Life in the wheat litter: effects of future climate on microbiome and function during the early phase of decomposition”. This study was performed on the conventional farming plots. We assessed the effects of climate change on microbial richness, community compositions, interactions and their functions (production of extracellular enzymes) in decomposing residues of wheat. In addition, we investigated the effects of climate change on litter residues physicochemical factors as well as on mass loss during the early phase of decomposition. Future climate significantly accelerated litter mass loss as compared with ambient one. Our results indicated that future climate significantly increased fungal richness and altered fungal communities over time, while bacterial communities were more resistant in wheat residues. Fungi corresponded to different physicochemical elements of litter under ambient (C, Ca2+ and pH) and future (C/N, N, P, K+, Ca2+ and pH) climate conditions. Also, a highly correlative interactions between richness of bacteria and fungi were detected under future climate. Activities of microbial β-glucosidase and N-acetylglucosaminidase in wheat straw were significantly higher under future climate. Such high enzymatic activities were coupled with a significant positive correlation between microbial (both bacteria and fungi) richness and community compositions with these two enzymatic activities only under future climate.:CONTENTS BIBLIOGRAPHIC DESCRIPTION……………………………………………….......III ZUSAMMENFASSUNG………………………………………………………...........V SUMMARY……………………………………………………………………………..X GENERAL INTRODUCTION…………………………………………………………………...............1 I-1 Ecosystem functions carried out by soil and plant microbiomes…………………..2 I-2 Biodiversity and functional diversity and maintenance of ecosystem functions……………..3 I-3 Total vs. active microbial diversity for assessing ecosystem functions……………4 I-4 Factors influencing soil and plant microbiota…………………………………..……6 I-4.1 Elements of climate changes……………………………………………................7 I-4.2 Climate changes influence microbes in an interacting, complex manner………8 I-4.3 Environmental factors controlling the response of microorganisms to climate changes………………………………………………………………………………….....10 I-5 Interplay between climate and land use intensity in agroecosystems……………11 I-6 Study site, and overall objectives………………………………………………....…12 I-7 Methods used for the taxonomic and functional characterization of the microbiomes……...15 I-8 Presentation of aims and hypotheses of the publications/manuscripts in different chapters.................................................................................................................16 I-9References.........................................................................................................20 CHAPTER 1 Can we use functional annotation of prokaryotic taxa (FAPROTAX) to assign the ecological functions of soil bacteria? .....................................................................29 Publication…………………………………………………………………………...........31 Supplementary materials…………………………………………………………….......42 CHAPTER 2 Targeting the active rhizosphere microbiome of Trifolium pratense in grassland evidences a stronger-than-expected belowground biodiversity-ecosystem functioning link………………..........................................................................…49 Publication………………………………………………………………………………51 Supplementary materials……………………………………………………………..67 CHAPTER 3 Deciphering Trifolium pratense L. holobiont reveals a microbiome resilient to future climate changes……………………………………………….…………………………..89 Publication………………………………………………………………………………….91 Supplementary materials……………………………………………………………….111 CHAPTER 4 Organic agricultural practice enhances arbuscular mycorrhizal symbiosis in correspondence to soil warming and altered precipitation patterns………………125 Publication……………………………………………………………………………….127 Supplementary materials………………………………………………………….......140 CHAPTER 5 Future climate significantly alters fungal plant pathogen dynamics during the early phase of wheat litter decomposition…...................………………….……………..156 Publication………………………………………………...…………….….…………...158 Supplementary materials………………………………………………….…....……..175 CHAPTER 6 Life in the wheat litter: effects of future climate on microbiome and function during the early phase of decomposition…………………………………….....……....…….181 Publication…………………………………..…………………………………….....…...183 Supplementary materials………………………………………………………………..199 GENERAL DISCUSSION…………………………………………………………….......210 D-I Approaches and main findings of the result chapters………………………..…211 D-2 Conclusion and implications of the study findings…………………………...…215 D-3 Technical limitation of the study……………………………………………......…217 D-4 Future prospects of the study field ...……………………………………………217 D-5 References…………………………………………………………………………..219 DATA AVAILABILITY……………………………………………………………………...223 ACKNOWLEDGEMENTS……………………………………………………………......224 CURRICULUM VITAE……………………………………………………………….....…225 LIST OF PUBLICATIONS………………………………………………………….........226 CONFERENCE PROCEEDINGS…………………………………………………….....227 STATUTORY DECLARATION………………………………………………................228 VERIFICATION OF AUTHOR PARTS……………………………………………........229
310

Urban Infilling Impacts On Florida Solid Waste Facilities

Nalamothu, Ravi Chander 01 January 2007 (has links)
Increasing urbanization in the US is leading to development or re-development of lands adjacent to solid waste facilities and these lands are being considered for residential communities and commercial projects. Thus, the potential for nuisance complaints against the pre-existing solid waste facility operations has become an increasing reality. The objective of this study was to develop a methodology to gather scientific and quantifiable data related to potential nuisances caused by landfills to determine setbacks and buffer zones near landfill and transfer station operations. Appropriate recommendations for these setbacks were made from case studies conducted at two landfills in Florida. The study involved making measurements related to odor, noise, litter and dust. Impact on housing prices was also evaluated by analyzing publicly available house price data. In this study volatile organic compound (VOC) concentration was used as a surrogate measure for gaseous impacts. The mass flux of VOCs was measured on the landfills using the dynamic flux chamber method. The ultimate purpose of flux measurements was to provide input data for dispersion modeling to analyze the extent of odor impact around the landfills, which is outside the scope of this study. Ambient measurements were also made around Landfill A for validating the dispersion model. Although there are no significant health and odor impacts caused by the landfill, higher background concentration extend 1.2-1.5 km from the landfill center on the Southeast side of the landfill. Litter from the road sides around the landfills was collected and catalogued based on size and material type. Litter count per site obtained for both landfills was less than the 2001 and 2002 state-wide counts. The difference was statistically significant. Noise measurements were made at landfills during incineration and landfilling. Based on average measurements (Leq) obtained at various distances from WTE facility and landfilling activity, and considering EPA recommended noise level of 55 dB(A) for a quiet neighborhood, a set back distance of 1.6-1.9 km was recommended. Impact on house prices near the landfills was done for four landfills in Florida. Analysis showed that three out of four landfills had significantly impacted the house price within 0.6-0.8 km from the edge of the landfill. Dust measurements were made at Landfill B using particulate samplers, quantifying the dust associated with landfilling. Measured values were below National Ambient Air quality Standard (NAAQ) for PM10. Finally, recommendations were developed to mitigate some of these nuisances

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