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Laing, Christopher Graham. "Methane from peat bogs : investigating zones of peak production." Thesis, Oxford Brookes University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501909.
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Organic matter has accumulated as peat in bogs since the last glacial retreat and its anaerobic decay by microbial communities produces methane (CH₄). CH₄ released from northern Boreal peat currently represents a significant proportion of the global budget but their contribution under future climates is uncertain. It is the surface peat 0-500 mm below the water table that is most important for emissions. This study aims to describe the vertical distribution of the gases CH₄, CO₂, O₂ and Ar and their fine scale (0.6 mm) variability in surface peat cores from a rain-fed bog using Quadrupole Mass Spectrometry (QMS). Direct links between the physical structure of peat and distribution of microbial communities have been investigated to identify the determinants of gas distribution.
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Cloy, Joanna Marie. "Chemical records of environmental pollution in ombrotrophic peat bogs." Thesis, University of Edinburgh, 2006. http://hdl.handle.net/1842/9427.
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Human activity has affected metal emissions to the atmosphere on a global scale for several thousand years, resulting in widespread contamination of the environment with toxic heavy metals such as Pb and Hg, thereby threatening both human and environmental health. In recent years ombrotrophic peat bogs have been used to study the changing rates and sources of atmospheric metal deposition, as they receive all their water and nutrients from the atmosphere by dry and wet deposition alone. Cores from such bogs have proved especially useful as archives of atmospheric Pb deposition as Pb is essentially immobile in ombrotrophic peat. The work described in this thesis is primarily concerned with the use of ombrotrophic peat bogs to investigate environmental contamination in Scotland during pre-industrial, industrial and post-industrial (i.e. ca. post-1970 A.D.) times. Cores were collected from ombrotrophic peat bogs at four different geographical locations (Carsegowan Moss, SW; Flanders Moss, W Central; The Red Moss of Balerno, E Central; Turclossie Moss, NE) in Scotland. Air-dried peat samples were dry-ashed and dissolved using microwave-assisted HF IHN03 digestion. Elemental concentrations (e.g. AI, As, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, P, Pb, S, Sb, Sc, Se, Ti, V, Y, Zn and Zr) and Pb isotope ratios (e.g. 206PbP07Pb) were determined using ICP-OES and ICP-MS as appropriate. For Hg determination, samples were digested with HN03/H2S04 and then analysed by CV AAS. Certified reference materials (e.g. Ombrotrophic Peat (NIMT/UOE/FM001), Canadian Peat (1878 P), Bush Branches and Leaves (DC73349), Peach Leaves (GBW 08501) and Coal (BCR CRM No. 40 and NBS SRM 1635) were used for quality control purposes. The distribution and behaviour of the potentially toxic trace elements (As, Cd, Co, Cr, Cu, Hg, Ni, Sb, Se, V and Zn) and of major elements (Ca, Fe, Mg, Mn, P and S) within the four ombrotrophic peat bogs was investigated and there was strong evidence that Ca, Fe, Mg, Mn, P, S, Se and Zn were mobile in ombrotrophic peat, while As, Cd, Co, Cr, Cu, Hg (at least during industrial and post-industrial periods), Ni, Sb and V, like Pb, were essentially immobile in ombrotrophic peat. Deposition records of conservative lithogenic elements (e.g. concentrations of AI, Sc, Ti, Y and Zr) that occur predominantly in soil dust were also investigated and the chosen conservative elements Sc, Ti and Zr were used in calculations to estimate anthropogenic enrichments of As, Cd, Co, Cr, Cu, Ni, Pb, Sb and V in peat bog profiles. 210Pb- and 14C- dated peat cores were used to reconstruct historical records of atmospheric anthropogenic As, Cd, Co, Cr, Cu, Ni, Pb, Sb and V deposition (since the pre-Roman (i.e. to ca. 380 B.C.)/Roman period) and atmospheric Hg deposition (since the onset of the industrial period) across Scotland. For Pb, on the basis of Pb isotopic composition (e.g. 206PbP Pb), clear indications of contamination during the preRoman/Roman and Mediaeval periods were attributed to the mining and smelting of Pb ores (from Britain and elsewhere in Europe). During the industrial and post-industrial periods, variations in the relative importance of contributions of anthropogenic Pb from different sources were apparent. From ca. the early 17th century A.D. at three of the peat bog sites, the mining and smelting of indigenous Scottish Pb ores, until the early 20th century A.D., were found to be the most important sources of anthropogenic Pb deposition. In contrast, at the most southerly site (Carsegowan Moss), influences from the use of both British Ph ores and imported Australian Ph ores (in more southern parts of Britain) since the late 19th century A.D. were evident. At each of the sites, the increasing importance of Australian-Ph-influenced car-exhaust emissions from the 1930s to late 1990s A.D., along with significant contributions from coal combustion (until the late 1960s A.D.) was evident. For Sb, in general, similarities between the major trends in the concentration profiles of anthropogenic Sb and Ph suggested common sources of these two elements. Perturbations in the anthropogenic Sb/Pb ratios since ca. 1800 A.D., however, were attributed to temporal variations in the relative importance of atmospheric emissions from different sources such as Ph ore mining/smelting, coal combustion and, in recent decades, automobile-related use of compounds of Ph (in leaded petrol) and of Sb (in brake linings). For Hg, in general, during the industrial and post-industrial periods, coal combustion and waste incineration, respectively, were likely to be the most important sources of Hg. For As, clear indications of contamination during the Mediaeval period were probably attributable to the mining and smelting of Ph and Cu ores, and for As, Cd, Co, Cr, Cu, Ni and V, during the industrial and post-industrial periods, a variety of sources (e.g. metallurgical activities, coal and oil combustion, use of phosphate fertilisers and waste incineration) were important to varying extents. Also, in recent years, atmospheric Cu emissions from automobile-related use of compounds of Cu (in motor oil, brake linings and tyres) may have been important. Inter-site and inter-elemental comparison of records of atmospheric metal deposition across Scotland indicated that, in general, atmospheric As, Cr, Hg, Ph and Sb deposition was greatest during the industrial period (between the late 1880s and late 1960s A.D.) and atmospheric Cd, Co, Cu, Ni and V deposition was greatest during the industrial and post-industrial periods (between ca. 1900 and the early 2000s A.D.), although increases in As, Co, Cr, Hg, Ph and Sb deposition were earliest (during the late 19th and early 20th century A.D.) at the most southerly site (Carsegowan Moss). During the industrial and post-industrial periods, levels of As, Ph and Cd contamination were generally highest in the south of Scotland, Cu, Co and Sb in south and central Scotland, and Cr, Ni and V in central Scotland. Overall, the existence of a south to north As, Cd, Co, Cr, Cu, Ni, Ph, Sb and V pollution gradient in Scotland was evident.
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Mazerolle, Marc J. "Amphibians in fragmented peat bogs, abundance, activity, movements and size." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ49408.pdf.
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Wilson, Pamela J. "Impact of peat cutting on the genetic diversity of plant populations in Northern Ireland peat bogs." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486238.
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The primary aim ofthis project was to use a range of molecular markers to estimate genetic diversity levels of a range ofcommon plant species in peatbogs, in cut and uncut areas of six differentbogs across Northern Ireland. The main species studied were the moss Polytrichum commune, the ericaceous angiosperm Calluna vulgaris, and the sedge Eriophorum vaginatum. For the moss, levels of genetic diversity were lower in fragmented populations, as predicted by population genetic theory. For the two higher plant species, no decrease in genetic diversity was found at the cut sites. Calluna vulgaris showed an increase in genetic diversity at cut sites, possibly associated with the effects of a substantial, soil seed bank, while for Eriophorum vaginatum all populations examined had a similar level of genetic diversity. The differences observ~d between the three species can be related to their different life . history traits. E. vaginatum and C. vulgaris are long lived species with the capacity for clonal growth and any detrimental effect of habitat fragmentation is likely to take many more generations to become apparent, if such an effect is to be observed. P. commune is a bryophyte where the haploid gametophyte is the dominant generation, with a short life span and a small dispersal distance compared to C. vulgaris and E. vaginatum, it is not unexpected that such a species would be the first to display the detrimental signs of habitat fragmentation. Based on the findings ofthis study, recommendations are made for the efficient conservation and management of peat bogs.
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Belyea, Liza Ruth. "Pattern and process in microhabitats of a raised bog." Thesis, Queen Mary, University of London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283297.
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Goodyer, Emma. "Quantifying the desmid diversity of Scottish blanket mires." Thesis, University of Aberdeen, 2014. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=212335.
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For the first time, presented within this thesis, is an investigation into the species richness and community composition of a group of beautiful but taxonomically challenging green algae - the desmids. This thesis represents the first account of a systematic sampling approach for desmid species and community assemblages in relation to national and local environmental variation. Sampling was focused on intact blanket mire with the aim of capturing a rich baseline dataset of desmid diversity. Previous works had highlighted desmids as being especially species rich in these acidic, nutrient-poor peatland habitats. A nested sampling approach was used to collect desmids from blanket mire microhabitats along the hummock-pool microtopographic gradient, from sites nationally within Scotland. This approach revealed remarkable species richness with 202 taxa sampled, including one new species. Distinct desmid communities were found to be strongly associated with the hummock-lawn-pool microhabitats within patterned blanket mire. This topographic aspect of peatland structure and its associated co-variables (such as pH and water table depth) also have a strong link to desmid diversity with the richest communities being found in association with a consistent supply of water close to the water table. Generally, ‘unstable' habitats supported lower desmid diversity. A field experiment was established to investigate the effects of drainage and drain restoration on desmid communities. This highlighted the loss of desmid diversity in drained peatlands and a successful but slow recovery of diversity upon restoration through drain blocking. The findings of this PhD project provide an understanding of the spatial scale of desmid community structure and the factors which are important for informing future conservation strategies for peatland habitats to maintain the diversity of this fascinating microbial group.
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Warren, Melissa. "Interactions between nitrogen fixation and methane cycling in boreal peat bogs." Thesis, Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53620.
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Microbial nitrogen (N2) fixation supplies important nitrogen inputs to boreal peatlands, extremely oligotrophic ecosystems dominated by Sphagnum mosses. In this study, we coupled major and trace nutrient analyses and rate measurements to characterize interactions between N2 fixation and CH4 cycling at the S1 peat bog in Marcell Experimental Forest and the Zim bog (Minnesota, USA). Total dissolved inorganic nitrogen (NO3-+NO2-+NH4+) and phosphate were both consistently < 2 μM in the porewater of surface peat, indicating severe nutrient limitation. While dissolved Fe was fairly abundant (18-35 mM), Mo, V and Cu were scarce (2-40 nM), suggesting that alternative metalloenzymes containing Fe in place of other metals may be favored. Rates of diazotrophy measured by both 15N2 incorporation and the acetylene (C2H2) reduction assay (ARA) were 7-fold higher under anoxic vs. oxic incubations conducted at both 4°C and 25°C. No significant difference in N2 fixation rates measured by either method was observed with or without the amendment of 1% CH4 at 25 °C; however, a significant inhibitory effect by methane was seen at 4°C in material from the S1 bog hollows. Anoxic 15N2 incorporation was 3-4x higher in treatments lacking acetylene, suggesting that the ARA likely underestimates N2 fixation by inhibiting diazotrophs sensitive to C2H2. Aerobic methanotrophy was also inhibited by 1% C2H2 when incubated under oxic conditions. No observations for the production of ethane (C2H6) were detected during the ARA, a biomarker for alternative nitrogenase activity. Major differences in ARA rates were observed to vary locally within microhabitats and between two bogs. In June 2014, peat sampled from hollows incubated under anoxic conditions showed the highest ARA rates (94.9 ± 11.0 nmol C2H4 g-1 moss dry mass hr-1), while the lowest rates were observed in
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hummock samples incubated under oxic conditions (5.1 ± 0.8 nmol C2H4 g-1 moss dry mass hr-1) in the S1 bog (T3 site). Observed rates have the potential to be a function of oxygen concentrations and or water content. ARA rates in all microcosm treatments were significantly lower at Zim bog compared to the S1 bog. The developed conversion factor between the regression of 15N2 and ARA in this study was 3.9 and agrees with the theoretical conversion factor as well as previous studies of soils and forest mosses.
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Yafa, Charun. "Accurate analysis and environmental geochemistry of inorganic elements in peat bogs." Thesis, University of Edinburgh, 2004. http://hdl.handle.net/1842/11632.
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The work described in this thesis is primarily concerned with (i) the development of analytical methods for the determination of inorganic elements in peat, (ii) the production and analysis of a certified peat reference material, and (iii) the application of methods and procedures to the generation and interpretation of elemental profiles in cores from the largest ombrotrophic peat bog in Scotland. The effects of sample preparation on the determination of inorganic elements in peak samples were thoroughly investigated. The analytical methods and quality assurance procedures developed using the certified reference material were applied to the analysis of two Flanders Moss peat cores that had been collected by different coring techniques. An offset between the elemental profiles of the two cores was attributed to loss of surface material in the case of one, confirmed by stable (206Pb/207Pb) and radioactive (210Pb) isotopic analysis. The depth profiles of the various elements were interpreted in terms of influences such as nutrient uptake and recycling, anthropogenic inputs from industry, energy generation and transport, soil dust, and post-depositional remobilisation and redistribution. For Pb, for which a record for atmospheric deposition was retained, the relative contributions of different sources (e.g. smelting, coal combustion, car-exhaust emissions) during the industrial era were assessed using Pb concentration and 206Pb/207Pb ratio variations in 210Pb-dated peat. The importance of atmospheric Pb deposition prior to the introduction of leaded petrol was confirmed and, in the more distant past, a small Pb peak at a depth of ~1 m was tentatively attributed to Pb mining and smelting activities during the period of the Roman Empire.
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Enrico, Maxime. "Atmospheric mercury deposition and mercury stable isotope compositions in peat bogs." Thesis, Toulouse, INPT, 2015. http://www.theses.fr/2015INPT0103/document.
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Les tourbières sont communément utilisées comme archives de dépôts de mercure (Hg). De nombreuses études ces dernières décennies ont montré que les taux d’accumulation de Hg (HgARs) ont augmenté en réponse à l’industrialisation. Les signatures isotopiques en Hg se révèlent très utiles pour mieux caractériser les dépôts de Hg. Elles ont permis de montrer que les dépôts secs de Hg élémentaire gazeux (GEM) dominent les dépôts de Hg sur la tourbière du Pinet. L’analyse d’échantillons de tourbe provenant de plusieurs tourbières en hémisphère nord montre que les dépôts secs de GEM dominent globalement les dépôts de Hg. Les tourbières pourraient donc être utilisées comme archives à la fois des dépôts humides et des concentrations en GEM pendant l’Holocène. On présente la première reconstruction quantitative des concentrations passées en GEM à partir de carottes de tourbe. L’impact de l’Homme sur le cycle du Hg a eu pour conséquence une augmentation graduelle des concentrations en GEM de 0,2 (10 000 – 4000 BP) à 3,5 ng m-3 (20ème siècle), accompagnée par des modifications de signatures isotopiques du Hg atmosphérique. Cette première utilisation de tourbières comme archives de concentration et d’isotopie du GEM est prometteuse, et devrait être étendue à la période pré-anthropique pour étudier les variations naturelles du cycle du Hg pendant l’HolocèneDuring the past few decades, peatlands were successfully used to investigate historical mercury (Hg) deposition. The chronology of Hg accumulation rates (HgARs) to peatlands is well constrained, with recent increases in HgAR associated with anthropogenic Hg emissions and deposition. The use of Hg stable isotopes in peatland ecosystems provides new opportunities to better characterize and understand historical Hg deposition. In an extensive study conducted at the Pinet peat bog (French Pyrenees) we identify gaseous elemental Hg (GEM) dry deposition, via foliar uptake, as the dominant Hg transfer pathway from the atmosphere to peat vegetation. Based on the Hg isotope analysis of multiple northern hemispheric peat records, we find that GEM dry deposition dominates Hg deposition globally. We suggest that peatlands can be used as archives of both past Hg wet deposition, Hg dry deposition and GEM concentration. We present the first quantitative reconstruction of historical atmospheric GEM concentrations using peat archives from the Pyrenees. The Human impact on Hg cycling caused a gradual increase in GEM concentrations from 0.2 (10,000 – 4000 BP) to 3.5 ng m-3 (20th Century) and was accompanied by a change in atmospheric Hg isotope signatures. This first comprehensive study on Hg isotope deposition to peatlands is promising and should be extended to pre-anthropogenic times to investigate natural variations in atmospheric Hg dynamics during the Holocene
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Stinglhammer, H. R. G. "Studies on factors affecting the structure of Arachnid communities on peat bogs." Thesis, University of the West of Scotland, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377917.
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Davidson, L. E. "Bulk density and carbon storage of lowland peat bogs in Northern Ireland." Thesis, Queen's University Belfast, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273078.
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Todd, Pamela Alexandra. "The ecological effects of mechanised peat extraction on blanket bogs in Northern Ireland." Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282339.
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Onyegbule, Peter Nnamdi. "Impact of Peat Bogs on the Brownification of River Storån and Lake Bolmen." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-42679.
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Freshwater bodies have been long observed to become browner within the northern hemisphere. This brownification, has made drinking water production difficult, since increased organic content in freshwaters requires higher dosages of chemicals during water treatment. Changes in land use through increased industrial forestry, decreased sulphur deposition from reduced industrial emissions, changing patterns of hydrological and meteorological parameters resulting from climate change, including recently highlighted increase in iron concentrations have been proposed to explain brownification. Drained peat bogs are man-made source of brownifying substances, capable of causing brownification in the rivers and lakes where the water ends up. This research is aimed at investigating dissolved organic matter, total organic carbon, iron, phosphorous, nitrogen and colour in bog ditches draining into the Storån River and Lake Bolmen in southern Sweden, in order to answer these research questions: (1) What are the differences in the level of water quality parameters, pH, conductivity, temperature, DOM, TOC, total phosphorous, total nitrogen, Fe and colour, between bog ditches and Storån River? And what could be the outcome of Colour absorbance comparison, between bog ditches, Storån and lake Bolmen as a single control sample? (2) Is there any association among the different water quality parameters, pH, conductivity, temperature, DOM, TOC, total phosphorous, total nitrogen, Fe and colour within the bog ditch water? Water samples from bog ditches and their corresponding Storån River locations, were used in the analysis. DOM and flow showed significant differences, after statistical test for difference. Conductivity, DOM, total nitrogen and total phosphorous exhibited significant correlations with pH. TOC also had a correlation with DOM., while colour correlated and depended strongly on Fe, within the bog ditches. Therefore, the bog ditch has behaved to contribute some amount of the brownification, found in Southern Swedish Lakes and Rivers. This knowledge might be useful in future, for more studies and control of Swedish fresh water brownification.
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Claricoates, Jane. "Gas production during peat decay." Thesis, Queen Mary, University of London, 1990. http://qmro.qmul.ac.uk/xmlui/handle/123456789/25734.
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Decay and accumulation of blanket peat in the Northern Pennine region of England are considered, both in quantitative and qualitative terms. Productivity on the surface of these peat bogs is not unusually high, suggesting that a low decay rate may be responsible for the accumulation of the peat. Considerable study has formerly been made of the aerobic decay processes, at the expense of the parallel anaerobic processes, which have largely hitherto been considered negligible. Yet a current mathematical model of peat accumulation suggests that it is likely to be the anaerobic decay rate which determines the total depth of peat which may accumulate. Further, such models intimate that a very small absolute change in the anaerobic decay rate will have an unexpectedly large effect on the potential steady state depth of peat. The present study concentrates on obtaining measurements of anaerobic decay rates, and on identifying the possible limiting environmental factors of the decay. The design of a sampler to collect gas samples in situ from blanket peat is described. The components of particular interest in the samples are CH4 and C02. Gas concentrations down eight peat profiles at two sites are monitored over two seasons. Simultaneous surface flux measurements above pool, lawn and hummock microhabitats are also made. Water level, temperature, pH, redox potential, depth of the sulphide zone and total sulphide concentration are recorded on each field visit. The results from the gas sample analyses are discussed in relation to the environmental factors and in relation to our present understanding of peat decay rates and their consequences on peat accumulation. The anaerobic decay rate is calculated, and is confirmed to be several orders of magnitude less than that in the overlying aerobic peat. It is shown that the methane is not fossil, but is continually being produced at all depths. Rates of gas production are calculated. Annual methane and carbon dioxide losses from entire peat bogs are calculated to contribute a significant amount to carbon cycling, on a site-specific and global scale.
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Sjöström, Jenny. "Reconstruction of Holocene atmospheric mineral dust deposition from raised peat bogs in south–central Sweden." Licentiate thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-153723.
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Atmospheric mineral dust plays a dynamic role in the climate system acting both as a forcing and a feedback mechanism. To date, the majority of paleodust studies have been conducted on marine sediments or polar ice cores, while terrestrial deposition has been less studied. As such, it is important to produce new terrestrial Holocene paleo–dust records and fill existing regional gaps. Ombrotrophic (atmospherically–fed) peat bogs can be used to reconstruct dust deposition through elemental chemistry analysis. Multi–elemental data sets are commonly used infer net dust deposition rates, source changes, grain size, and mineral composition. Mineralogical identification of dust particles is particularly important because it allows both provenance tracing and increased understanding in climate and ecosystem feedbacks. Establishing mineralogy from elemental data of mixed mineral matrixes can however be challenging. X–ray diffraction analysis (XRD) is a standard technique for mineral identification which ideally requires removal of organic matter (OM). Therefore, a test procedure was undertaken where common OM removal methods were evaluated on bulk peat samples was therefore undertaken. The results showed that combustion at 500°C was most efficient in removing OM, while leaving the majority of minerals intact, but not all. In this Licenciate thesis, early result of a paleodust study from Draftinge Mosse, southern Sweden, are also outlined. Here, the method development mentioned above was applied, enabling a combination of elemental data with mineralogy. Future work includes minor and trace element analysis by ICP–AES and ICP–MS, evaluation of the reproducibility of single core reconstructions, tests of some of the methodological assumptions used in previous paleodust studies, source tracing and paleodust reconstruction from a second site (Gällsered Mosse).Atmosfäriskt mineraldamm, mineralpartiklar som lyfts upp i atmosfären och avsätts via eoliska processer, spelar en komplex roll i klimatsystemet då partiklarna påverkar klimatet, samtidigt som rådande klimat också påverkar partikelmängden. De flesta hittills genomförda mineraldamms- studier har utförts på marina sediment eller iskärnor trots att mineraldammspartiklar i störst utsträckning deponeras på kontinenterna. Ombrotrofa mossar (högmossar) kan användas för att rekonstruera avsättning av mineraldamm över tid genom geokemiska analyser på olika djup i torvkärnor. Den kemiska sammansättningen ger information som kan användas för att härleda variationer i partikelmängd, källområden, kornstorlek, samt mineralogisk sammansättning. Bestämning av mineralen är av särskild vikt då det möjliggör identifikation av partiklarnas källområden samt ger kunskap om partiklarnas del i klimat- och ekosystem processer. Att via geokemiska data identifiera mineral prover av blandad sammansättning är dock utmanande, särskilt då många mineral har en liknande kemisk sammansättning. Röntgen diffraktions analys (XRD) är en standardmetod inom berggrundsgeologi för att identifiera mineral, som här används på torvprover. Metoden är icke-destruktiv, men kräver att provet är relativt rent från amorfa faser, så som organiskt material. Då torv innehåller stora mängder organiskt material (>98 %), som dessutom karaktäriseras av att vara svårnedbrutet, utformades ett testprotokoll för att studera vilken metod som är bäst lämpad för att ta bort organiskt material från denna specifika jordtyp. Resultaten från genomförda tester visade att förbränning (500°C) är mest effektivt och även lämnade en majoritet av mineralen intakta, dock inte alla. I denna licenciatavhandling beskrivs även de övergripande målen med min forskning samt tidiga resultat från en mineraldammstudie från Draftinge mosse (Småland), där resultaten från metodstudien ovan applicerats och kombinerats med andra geokemiska data. Vidare arbete inom detta doktorandprojekt kommer innefatta ytterligare geokemiska analyser (spårämnesanalys med ICP-MS och ICP-AES) samt identifiering av källområden. Dessutom kommer ytterligare en mosse (Gällsered mossse) att studeras för förändringar i avsättning av mineraldamm under de senaste 7000 åren.
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Money, Russ Philip. "Restoration of lowland raised bogs damaged by peat extraction : with particular emphasis on Sphagnum regeneration." Thesis, University of Sheffield, 1994. http://etheses.whiterose.ac.uk/1860/.
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1. Revegetation trends in abandoned peat workings indicate that peat cuttings are generally too dry for spontaneous re-establishment of raised bog vegetation. The latter was restricted to small flooded peat pits which had recolonised 'hydroserally' to support floating rafts of bog vegetation. 2. The water storage capacity of cut-over bog surfaces is low compared with undisturbed bog and blocking drains in a peat field at Thorne Moors, S. Yorks, was insufficient to prevent water-table instability. Experiments suggest this may severely inhibit Sphagnum growth. Lagoons may increase water storage on a bog surface and facilitate development of raised bog vegetation as floating rafts. This 'hydroseral' approach may be necessary to restore raised bog vegetation to some areas. 3. Hydrochemical conditions of cut-over sites may differ significantly from undisturbed bogs with implications for Sphagnum growth. Water samples from a peat field at Thorne Moors were comparatively acidic and contained comparatively high concentrations of most major ions (particularly NH4 and SO4), except phosphorus. Moderate nutrient enrichment is unlikely to adversely affect Sphagnum and additions of phosphorus to flooded peat pits significantly increased its growth. In solution culture, low pH (3.0-3.5) was sub-optimal for Sphagnum growth, but the use of CaCO3 to reduce acidity in the field had a toxic effect. 4. Sphagnum recolonisation may be limited by availability of propagules in cut-over areas. Experiments indicate that deliberate re-introduction encourages Sphagnum raft development, which is pioneered by aquatic species that regenerate more prolifically from fragments than intact gametophytes. Sphagnum rafts are encouraged in shallow water (< 5 0cm) and pools of small area. Numerous management options exist physically and chemically assisting raft development.
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Long, Kevin D., and Thesis (University of Lethbridge Faculty of Arts and Science). "Methane fluxes from a northern peatland : mechanisms controlling diurnal and seasonal variation and the magnitude of aerobic methanogenesis." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2008, 2008. http://hdl.handle.net/10133/744.
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Continuous eddy covariance measurements were conducted for a 125 day period, throughout the 2007 growing season, in a northern Alberta peatland. Significant diurnal and seasonal variation in methane fluxes were observed. Diurnal variation in methane flux was suggested to be due to variation in soil temperature and methane convective flow through vegetation to the atmosphere. Seasonal variation in methane flux was associated with a variety of factors, most notably seasonal variation in the capacity for methane emission at 10 ºC (R10). The R10 values varied as a function of soil temperature and were an important control of seasonal variation in methane flux. Also, a greenhouse gas budget was calculated comparing net methane emission and net CO2 sequestration. This analysis indicated that the peatland was acting as a net sink of radiative forcing agents for the 2007 growing season.xiii, 100 leaves ; 29 cm. --
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Grégoire, Taillefer Amélie. "Colonization of restored peatlands by insects : Diptera assemblages in mined and restored bogs in eastern Canada." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112626.
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The impact of peatland restoration on Diptera assemblages was studied across multiple organizational levels (taxon, size class, trophic group) among abandoned-mined, restored and natural sites of three bogs and the environmental variables affecting those assemblages were determined. More than 22,000 individuals representing 716 species were collected using pan traps, sweeping and Malaise traps. Restored and abandoned sites were similar to each other and both distinct from natural sites as shown by small-size class, acalyptrate and trophic assemblages. However, abandoned sites showed much lower evenness and generally supported lower species richness than restored and natural sites, due to the dominance of one or two saprophagous species. The coverage of bare peat, Sphagnum mosses and ericaceous shrubs explained most of the variance in species composition. Those results suggest that restoration enhanced the recovery of high species diversity, although more than seven years are needed to recover a complete trophic structure or to enable species with low dispersal ability to recolonize to pre-disturbance levels.
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Givelet, Nicolas. "Long-term records of atmospheric deposition of mercury in peat cores from Arctic, and comparison with bogs in the temperate zone /." [S.l.] : [s.n.], 2004. http://www.zb.unibe.ch/download/eldiss/04givelet_n.pdf.
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McEnroe, Nicola A. 1973. "Carbon biogeochemistry of open water pools on an ombrotrophic raised bog, James Bay, Québec, Canada." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115691.
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Carbon (C) biogeochemical cycling studies in northern peatlands, in particular the production, consumption, storage and emission of C gases (CO2 and CH4) over space and time between different peatland landforms can help in understanding their current and future role in the global C cycle. In some peatlands, a distinct surface patterning of vegetation, interspersed with open water pools, controls the spatial and temporal variability in CO 2 and CH4 exchange to atmosphere. These open water pools initially develop from shallow, flooded hollows to deeper water bodies and at some point reach a limit in their depth. Observations link pool size to age and spatial location on the peatland surface and over time the proportional cover of pools increases, playing an important role in the long-term peatland C balance.The processes responsible for the production of CO2 and CH 4 in pools remain unexplored. In particular, the contribution of pools to the peatland C balance over the timeframe of the development of a pool complex is not explained and pools are not incorporated into current peatland models. A field study was carried out to examine the exchange of CO2 and CH4 from pools to atmosphere and to explore the spatial and temporal dynamics in CO2, CH4 and DOC storage in pools of different size and spatial location. This was undertaken to improve the understanding of the processes responsible for the generation of CO 2 and CH4 over the timescale of pool development. The empirical study was carried out during spring, summer and fall over two years in an ombrotrophic, raised bog, Quebec, Canada. A modelling component was carried out to examine the contribution of pools to the long-term peatland C balance.
Measurements of dissolved concentrations and emissions of CO2 and CH4 from pool surfaces to atmosphere were different among pools of different sizes and spatial location. Shallow pools had consistently higher emissions of both CO2 and CH4 and higher water column dissolved CO2 and DOC concentrations. Deeper pools had greater concentrations of sediment CH4. Dissolved organic carbon in pools was allochthonous, with a greater concentrations and proportion from higher plant materials in shallow pools, likely contributing to the observed water column CO2 concentrations and greater CO2 emissions.
All pools were supersaturated with dissolved CO2 and CH 4 at the time of sampling, with shallow pools up to eight times atmospheric equilibrium concentrations for CO2 and concentrations were up to one hundred times greater than CH4, comparable to findings in other global freshwater systems. Results suggest that greater decomposition is occurring in shallow pools due to warmer water and basal sediment temperatures and increased light penetration and dissolved oxygen (00) and that greater CH4 production and oxidation accounts for some of the differences reaching a limit at 0.7 m deep. Even though this range of pools are not as deep as pools found on other northern peatlands, the results provide evidence for the potential processes responsible for the generation of CO2 and CH4 emissions to atmosphere and demonstrate that pools have a significant role in the short and long-term peatland C balance. Modelling the hypothesised processes responsible for the generation of CO2 and CH4 shows that if sediment decomposition is the major source of these gases then the dynamical link between pool sediments, C gas production and pool growth has been demonstrated. Ultimately their role as source or sink is largely determined by their size (depth), the proportional cover on the landscape and their rates of C storage in sediments versus rates of C uptake and exchange.
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Fritz, Christian. "Surface oscillation in peatlands : how variable and important is it? /." The University of Waikato, 2006. http://hdl.handle.net/10289/2397.
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Hydrology, particularly the water table position below the surface, is an mportant control on biogeochemical and ecological processes in peatlands. The position of the water table is a function of total storage changes, drainable porosity and peatland surface oscillation (PSO). Because the absolute level of the peat surface (ASL) oscillates in a peatland, we can assign two different water table positions: the water table depth below the surface (relative water level, RWL) and the water table position above an absolute elevation datum eg. sea level (absolute water level, AWL). A review of 37 studies that report peatland surface oscillation indicate awide range (0.4-55 cm), which is to the same order as (or one order smaller than) water storage changes and RWL fluctuations. PSO can vary substantially across a single peatland and through time. A set of mechanisms (flotation, compression/shrinkage, gas volume changes and freezing) is hypothesised to cause ASL changes. The potential of PSO to reduce RWL fluctuations trended (mean in %) floating peatlands (63) greater than bogs (21), fens (18) greater than disturbed peatlands (10) with respect to peatland types. To investigate the spatiotemporal variability of peatland surface oscillation, AWL and ASL were monitored continuously over a one-year period (one site) and monthly (23 sites) in a warm-temperate peatland that is dominated by Empodisma minus (Restionaceae). A new measurement method was developed by pairing two water level transducers, one attached to a stable benchmark (AWL) and one attached to the peat surface (RWL). From August 2005 until August 2006 the ASL oscillated at one site through a range of 22 cm following AWL fluctuations (in total 47 cm). Consequently, RWL fluctuations were reduced on average to 53% of AWL fluctuations. The strong AWL-ASL relationship was linear for 15 sites with manual measurements. However, eight sites showed significantly higher rates of peatland surface oscillation during the wet season (ie. high AWLs) and thus a non-linear behaviour. Temporary flotation of upper peat layers during the wet season may have caused this non-linear behaviour. On the peatland scale AWL fluctuations (mean 40 cm among sites) were reduced by 30-50% by PSO except for three sites with shallow and dense peat at the peatland margin (7-11%). The reduction of RWL fluctuation was high compared to literature values. The spatial variability of PSO seemed to match well with vegetation patterns rather than peat thickness or bulk density. Sites with large PSO showed high cover of Empodisma minus. Surface level changes exhibited surprisingly hysteretic behaviour subsequent to raised AWLs, when the rise of ASL was delayed. This delay reversed the positive ASL-AWL relationship because the surface slowly rose even though AWL started receding. Hysteresis was more pronounced during the dry season than during the wet season. The observed hysteresis can be sufficiently simulated by a simplistic model incorporating delayed ASL fluctuations. PSO has wide implications for peatland hydrology by reducing RWL fluctuations, which feed back to peat decomposition and plant cover and potentially to (drainable) porosity. Stable RWL also reduce the probability of surface run-off. It is further argued that the gas content of the roots of plants, particularly Empodisma minus, added enough buoyancy to detach the uppermost peat layers resulting in flotation.
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Fraser, Colin J. D. "The hydrology and dissolved organic carbon (DOC) biogeochemistry in a boreal peatland /." Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=30383.
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A hydrological and biogeochemical study was undertaken at the Mer Bleue bog, Ottawa, Ontario, Canada from May 22, 1998 to May 21, 1999. Basin runoff was generated by groundwater discharge at the peatland margin, and groundwater discharge was controlled by hydraulic gradients and horizontal hydraulic conductivities (Kh). Flux of dissolved organic carbon (DOC) measured at the basin outflow was 8.3 g C m-2 yr-1 and compared to within 23% of DOC flux estimated using a Dupuit approximation of seepage during the ice-free season. Annual DOC flux was 11% of the annual carbon sink.Flownet analysis showed that seasonal patterns of groundwater flow were controlled by boundary condition changes that resulted from precipitation and evapotranspiration events. A pattern of recharge was most common over the hydrological year, but a discharge pattern was observed during a 40 day groundwater flow reversal. Evaluation of the peatland recharge-discharge function using in situ sodium concentrations and a diffusion model revealed that the peatland is a long-term recharge system. It is hypothesized that peatland biogeochemical function is controlled by long-term recharge despite annual occurrence of groundwater flow reversals.
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Naudin, Aline. "Potentiel de la minéralogie magnétique en tant que marqueur des variations environnementales enregistrées par les dépôts tourbeux : Application au marais de la Trézence (17)." Phd thesis, Université de La Rochelle, 2011. http://tel.archives-ouvertes.fr/tel-00703444.
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L'utilisation de la minéralogie magnétique en tant que marqueur des changements environnementaux dans les tourbières a été envisagé dès 1986 (Richardson, 1986) mais n'a pas été réellement prise au sérieux jusque très récemment (Hutchinson and Armitage, 2009; Mighall et al., 2009). Notre étude se proposait d'abord de déterminer quelles techniques sont les plus adaptées à des mesures sur tourbe (acquisition progressive d'ARI et ARA associées à leurs désaimantations AF) et comment les mettre en place afin de garantir la qualité des mesures malgré les nombreuses contraintes : faiblesse du signal, évolution temporelle de la minéralogie, caractère meuble et instable des dépôts. Le protocole d'étude de la minéralogie magnétique a ensuite été appliqué à trois carottes prélevées dans le marais de la Trézence (Charente-Maritime, France) en parallèle d'analyses géochimiques à même de retracer l'histoire environnementale du site (analyse élémentaire, isotopes du plomb, rapport C/N,datations radiocarbones). A la confrontation des résultats, il apparaît qu'une partie des variations de minéralogie magnétique correspond aux indications environnementales apportées par les paramètres géochimiques. Les autres variations mises en exergues peuvent être interprétées en termes d'indicateurs de processus pédologiques non observable avec les paramètres géochimiques étudiés.
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Poto, Luisa <1984>. "Reconstruction of Holocene climate dynamics in the Dolomites from a peat bog core : the first multi-proxy study." Doctoral thesis, Università Ca' Foscari Venezia, 2014. http://hdl.handle.net/10579/4664.
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Paleoclimate and paleoenvironmental studies in the North-Eastern Italian Alps are hampered by the rarity of well-preserved high-altitude deposits and the lack of high-resolution multi-proxy records with adequate chronological control. Records from peat-bogs have been demonstrated to be among the best tools in paleoenvironmental studies to reconstruct past climate conditions and variations in atmospheric composition.
An ombrotrophic peat bog is a domed peatland hydrologically isolated from the influence of local groundwaters and surface waters, in which the surface layers are supplied only by atmospheric depositions. For this reason, they constitute an authentic records of information about past and present patterns in global climatic change.
Here we present the first complete Late Glacial to Holocene peat bog succession from the Dolomites (Danta di Cadore, Belluno, Italian Alps).
In 2011 a 7.0 m deep peat bog core was drilled at Val di Ciampo (Belluno province, 1400 m a.s.l.) and its potential as a paleoclimatic and paleoenvironmental archive has been evaluated.
The depth-age scale is based upon independent 14C and 210Pb dates, modelled with ''Clam'' method, this combined with peat stratigraphy, demonstrates that the peat core covers more than 13,200 years (cal BP), extending back to the end of the last part of the Late Glacial.
We determined bulk density, inorganic matter content, and several parameters of pore water such as pore water pH, conductivity, Ca/Mg ratios, and Ca and Ti trends, to identify changes in trophic conditions through the entire profile. This multi-proxy approach confirms that the uppermost 400 cm of the bog are ombrotrophic, and demonstrates that this core is the longest Eastern Alpine ombrotrophic record yet obtained, covering the last 7,000 years.
Chronological constraints of the course of deglaciation in the Southern Alps are fewer than those available for the northern slope of the Alps. For the Piave basin, the mode and timing of deglaciation are well-defined only for the its mid-part, while no data are available for the upper section. In such a context of very limited data the oldest radiocarbon age (13,110-13,330 years cal BP) represents a very valuable result, providing clear evidence that, during the Bolling-Allerod interstadial, the upper part of the Piave Glacier was ice free, and confirming that the retreat process of Piave Glacier from the Last Glacial Maximum was very rapid.
Pollen assemblages at the transition from the Late Glacial to the Early Holocene were studied at high resolution. In this time frame pollens show that
denser forests of Gymnospermeae were present during the Bolling-Allerod interstadial (at approximately around 13,200 years cal BP), and were reduced by the climatic cooling of the Younger Dryas (12,600 - 11,500 years cal BP), when a more open type of vegetation spread. Then, with the beginning of the Holocene, forests developed again with the expansion of species such as Corylus, a warmth-requiring tree.
The investigation of atmospheric deposition during the Holocene is extremely important because it provides information about the climate-related changes in the atmospheric composition as well as the impact of human activities on the environment.
With this aim, the concentration of 44 trace elements have been determined at a resolution of 1 cm on the first meter of the bog.
X-ray Fluorescence Core Scanner (XRF-CS) analysis was here applied for the first time on peat bog sequences. Results were combined with those obtained by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), providing information about geochemical processes occurring in the bog, and about their influence on major and trace elements distribution along the profile.
XRF-CS signals were calibrated using ICP-MS results, showing very high correlation and demonstrating that even the XRF-CS technique, when applied to peat samples, provides reliable quantitative results.
Particular attention was directed to elements related to mining activity, that has characterized the history of the Cadore region since the Middle Ages. Pb, Ag, Cd concentrations and Enrichment factors (EFs) were determined in the upper 100 cm of the record. In addition lead isotopes were also measured. Concentration levels and EFs of several trace elements such as Pb, Ag and Cd, fit very well the documented chronology about mining activity in Cadore region, indicating that the Val di Ciampo bog recorded the development and the history of mining exploitation at least at a regional scale.
In particular, the Pb, Ag and Cd maximum concentrations are recorded between 1950s and 1980s, time interval that corresponds to the highest activity of the mining sites.
Lead isotopes ratios were measured to identify natural and anthropogenic sources of Pb emissions in the first metre of the bog. The isotopic composition of lead shows an increase of Pb deriving from fuel combustion over the last decades that gradually overlie the impacts of mining activity. In fact the uppermost 28 cm (corresponding to the period between AD 1940 and 2011) are characterized by more radiogenic inputs due to leaded gasoline combustion, with a signature closer to coal and fuel.
Specifically, the 206Pb/207Pb decreasing trend, indicator of increasing leaded gasoline combustion, reached the minimum value of 1.153 in the 1990s (that correspond to maximum value of Pb flux, 0.75 g cm-2y-1 and then increases again. In these years, in fact, Italy started to follow EU rules to limit global pollutants in the atmosphere, and finally in 2002 banned leaded-fuels.
Val di Ciampo demonstrates a record not only of global (e.i. leaded gasoline combustion) or local (e.i. mining activity) changes in atmospheric inputs, but also more regional trends. In fact, both 206Pb/207Pb and Pb flux show a particular event between 1975 and 1980: this behaviour is characteristic of the ILE experiment (Isotopic Lead Experiment), a large scale isotopic tracer experiment that was carried out in the Piedmont region of Northwest Italy to study the metabolic paths of this element into the environment. All the gasoline used was labelled with a well isotopically-defined Pb.
The high-resolution physical, chemical and biological data obtained from the analysis of this peat archive improve our understanding of European Alpine Holocene climate and environmental variability and the relationship between natural fluctuations and anthropogenic impacts.
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Böhm, Anna Katharina. "Hochmoore im Erzgebirge - Untersuchungen zum Zustand und Stoffaustragsverhalten unterschiedlich degradierter Flächen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2006. http://nbn-resolving.de/urn:nbn:de:swb:14-1166088240387-85412.
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Die Hochmoore des Erzgebirges sind auf Grund ihrer jahrhunderte langen Nutzung und der ökosystemaren Wandelprozesse der vergangenen 10 - 15 Jahre unterschiedlich stark degradiert. Gleichzeitig sind sie durch den Austrag vergleichsweise hoher Austräge von DOC (Dissoloved Organic Carbon) gekennzeichnet. Um den Zusammenhang zwischen dem Zustand der Hochmoore, als Ergebnis in erster Linie der unterschiedlich nutzungsbedingten Degradation und den Stoffausträgen speziell den DOC-Austrägen zu erfassen, wurden mittels landschaftsökologischer Methoden Hochmoortestflächen verschiedener Zustände vergleichend untersucht. Die Ergebnisse lieferten erste Hinweise, dass in Flächen mit natürlicher Regeneration oder anthropogener Wiedervernässung vergleichsweise hohe DOC-Konzentrationen und – Austräge zu beobachten waren. Demgegenüber standen stärker degradierte Flächen mit zum Teil aktueller forstlicher Nutzung (geräumte Entwässerungsgräben), die durch geringere DOC-Konzentrationen und – Austräge charakterisiert waren. Da die gefundenen Zusammenhänge nicht endgültig belegt werden konnten, besteht insbesondere Forschungsbedarf hinsichtlich landschaftshaushaltlicher Untersuchungen unterschiedlich degradierter Hochmoore im ErzgebirgeNatural peat bogs are known as a sinks especially for carbon because of theire special matter and water balance. The use of peat bogs requiers their drainage, but consequently the peat will decompose unreversible and peatlands turn to a source esspecially for carbon. The peat bogs in the “Erzgebirge Mountains” were used over several centuries. Thats why the peatlands existing nowadays have different states dependent on the duratian of their use. Beside the use peatlands were mostly negativly effected by processes of ecological change in the “Erzgebirge Maountains” in the last 10 to 15 years. As one result of ecological change the increased output of DOC (Dissolved Organic Carbon) into surface waters can be seen. The main source for DOC are peatlands. By the way it seems to exist a connection between the output of DOC and other dissolved substances and the state of the peatlands especially of their ditches. To research this hypothesis four test areas of different state were chosen. Their state and the output of DOC and other dissolved substances were investigated with methods from landscape ecology from 2001-2003. It was the first time, that peatlands in the “Erzgebirge Mountains” were investigated in such a way. The badest state had the test area where the ditches were cleaned in 2000/ 2001 (“Weiße Mulde”, Western “Erzgebirge Mountains”). This test area showed the lowest but constant DOC-concentrations and DOC-output during the investigation period. The test areas “Carlsfeld” and “Löffelsbach” (Western “Erzgebirge Mountains”) had the best state. The state of “Carlsfeld” is related to the narueal closed ditches, which cause the processes of self regeneration. Due to such processes the DOCconcentrations were distinctly higher but very variable in dependence on weather and runoff. The same was supposed to DOC-output. The same valuation got the test area “Löffelsbach”, because of rewetting by technical closed ditches in 2001. During the investigation period the highest DOC-concentrations of all test areas were measured there. Similar to “Carlsfeld” DOC-concentrations and –output were highly variable in dependence on weather and runoff. The state of the test area “Salzflüßchen” (Eastern “Erzgebirge Mountains”) is also related to processes of self regeneration but was valuated bader than “Carlsfeld”, because the effect of former drainage was stronger in this area. In 2005 the rewetting of the test area is planed by “Naturpark Erzgebirge/ Vogtland”. In the consequence the DOC-concentrations and –output will increase similar to “Löffelsbach”. The results of the investigations indicate that a connection exists between state of peatlands and output of dissolved substances esspecially DOC. The results are supported by national and international literature. It will be clear, that more research is necessary especially on the field of comparative investigations of peatlands with different states in the “Erzgebirge Mountains”
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Kebaili, Caroline. "Impact de l'homme et du climat sur l'histoire démographique de 4 espèces emblématiques de papillons des tourbières de Franche Comté, et implications pour la gestion conservatoire." Electronic Thesis or Diss., Université Grenoble Alpes, 2023. http://www.theses.fr/2023GRALV111.
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L’érosion de la biodiversité est un enjeu majeur du 21ème siècle. La perte massive d’espèces au cours des dernière décennies a profondément perturbé les écosystèmes et compromis les multiples services qu’ils rendent aux sociétés humaines. Parmi les principaux facteurs de cette érosion se trouvent le réchauffement climatique et la dégradation ou la destruction des habitats du fait des activités anthropiques. Ce dernier facteur contribue à l’augmentation de la fragmentation des habitats et nuit à la connectivité paysagère. Or, elle est essentielle au maintien des espèces vivant au sein de métapopulations et/ou ayant une capacité de dispersion limitée.La connectivité paysagère est une des principales préoccupations des gestionnaires de milieux naturels. C’est le cas pour quatre espèces de papillons des tourbières jurassiennes (la Nacré de la canneberge Boloria aquilonaris, le Fadet de tourbières Coenonympha tullia, le Cuivré de la bistorte Lycaena helle et le Mélibée Coenonympha hero) qui, malgré les nombreux efforts de conservation et la protection de leur habitat par un programme LIFE, montrent encore des signes de déclin et sont inscrites sur les listes rouges UICN françaises et franc-comtoises.Les objectifs de cette thèse étaient (i) d’étudier la structure et la diversité génétiques des populations de ces espèces dans le massif du Jura et de mettre en évidence les éléments de leur histoire démographique post-glaciaire qui avaient pu contribuer à cette structuration, (ii) de mettre en place une méthodologie permettant de modéliser la mosaïque complexe de milieux qui compose le paysage dans lequel les espèces évoluent, et (iii) de modéliser la connectivité paysagère des espèces afin d’orienter de futures mesures de gestion.L’analyse génétique a révélé des états de conservation variables pour les quatre espèces, montrant une situation préoccupante pour C. tullia et B. aquilonaris et plutôt stable pour L. helle et C. hero. L’histoire démographique est commune et dévoile une recolonisation post-glaciaire du massif jurassien par le Nord. La comparaison de graphes génétiques et paysagers s’est montrée efficace pour paramétrer les surfaces de résistance paysagère complexes et ses résultats ont été utilisé pour modéliser la connectivité, en association avec des données écologiques à dires d’expert. Une zone à fort enjeu de conservation, située au centre du massif, a été identifiée pour L. helle, C. tullia et B. aquilonaris, ainsi qu’une déconnexion apparente avec les autres régions de massif, au moins pour les deux dernières espèces.L’intérêt démontré de l’utilisation conjointe de données génétiques et écologiques pour analyser la connectivité, issue de la proche collaboration entre la recherche et le terrain, illustre la complémentarité de la modélisation et du suivi de terrain pour la conservation de la biodiversitéL’intérêt démontré de l’utilisation conjointe de données génétiques et écologiques pour analyser la connectivité, issue de la proche collaboration entre la recherche et le terrain, illustre la complémentarité de la modélisation et du suivi de terrain pour la conservation de la biodiversité.The erosion of biodiversity is a major issue of the 21st century. The massive loss of species over the past decades has profoundly disrupted ecosystems and compromised the multiple services they provide to human societies. Among the main factors of this erosion are global warming and the degradation or destruction of habitats due to anthropogenic activities. This last factor contributes to increase habitat fragmentation and is deleterious to landscape connectivity. However, it is essential for maintaining species with limited dispersal capacities and/or living in metapopulations.Landscape connectivity is one of the main concerns of managers of natural environments. This is the case for four species of peta bogs butterflies from Jura (the Cranberry fritillary Boloria aquilonaris, the Large heath Coenonympha tullia, the Violet copper Lycaena helle and the Scarce heath Coenonympha hero) which, despite numerous conservation efforts and the protection of their habitat through a LIFE program, still show signs of decline and are included on the French and Franche-Comté IUCN red lists.The objectives of this thesis were (i) to study the population genetic structure and diversity of these species in the Jura massif and to highlight the elements of their post-glacial demographic history which may have contributed to this structuring, (ii) to establish a methodology to model the complex mosaic of environments that make up the landscape in which species live, and (iii) to model the landscape connectivity of species in order to guide future management measures.Genetic analysis revealed variable conservation states for the four species, showing a worrying situation for C. tullia and B. aquilonaris and rather stable for L. helle and C. hero. The demographic history is common and reveals a post-glacial recolonization of the Jura massif from the North. The comparison of genetic and landscape graphs has proven effective in parameterizing complex landscape resistance surfaces and its results have been used to model connectivity, in association with expert ecological data. An area of high conservation concern, located in the center of the massif, has been identified for L. helle, C. tullia and B. aquilonaris, as well as an apparent disconnection with the other regions of the massif, at least for the last two species.The demonstrated interest in the joint use of genetic and ecological data to analyze connectivity, resulting from close collaboration between research and the field, illustrates the complementarity of modeling and field monitoring for the conservation of biodiversity
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Böhm, Anna Katharina. "Hochmoore im Erzgebirge - Untersuchungen zum Zustand und Stoffaustragsverhalten unterschiedlich degradierter Flächen." Doctoral thesis, Technische Universität Dresden, 2005. https://tud.qucosa.de/id/qucosa%3A24805.
Full textAbstract:
Die Hochmoore des Erzgebirges sind auf Grund ihrer jahrhunderte langen Nutzung und der ökosystemaren Wandelprozesse der vergangenen 10 - 15 Jahre unterschiedlich stark degradiert. Gleichzeitig sind sie durch den Austrag vergleichsweise hoher Austräge von DOC (Dissoloved Organic Carbon) gekennzeichnet. Um den Zusammenhang zwischen dem Zustand der Hochmoore, als Ergebnis in erster Linie der unterschiedlich nutzungsbedingten Degradation und den Stoffausträgen speziell den DOC-Austrägen zu erfassen, wurden mittels landschaftsökologischer Methoden Hochmoortestflächen verschiedener Zustände vergleichend untersucht. Die Ergebnisse lieferten erste Hinweise, dass in Flächen mit natürlicher Regeneration oder anthropogener Wiedervernässung vergleichsweise hohe DOC-Konzentrationen und – Austräge zu beobachten waren. Demgegenüber standen stärker degradierte Flächen mit zum Teil aktueller forstlicher Nutzung (geräumte Entwässerungsgräben), die durch geringere DOC-Konzentrationen und – Austräge charakterisiert waren. Da die gefundenen Zusammenhänge nicht endgültig belegt werden konnten, besteht insbesondere Forschungsbedarf hinsichtlich landschaftshaushaltlicher Untersuchungen unterschiedlich degradierter Hochmoore im Erzgebirge.Natural peat bogs are known as a sinks especially for carbon because of theire special matter and water balance. The use of peat bogs requiers their drainage, but consequently the peat will decompose unreversible and peatlands turn to a source esspecially for carbon. The peat bogs in the “Erzgebirge Mountains” were used over several centuries. Thats why the peatlands existing nowadays have different states dependent on the duratian of their use. Beside the use peatlands were mostly negativly effected by processes of ecological change in the “Erzgebirge Maountains” in the last 10 to 15 years. As one result of ecological change the increased output of DOC (Dissolved Organic Carbon) into surface waters can be seen. The main source for DOC are peatlands. By the way it seems to exist a connection between the output of DOC and other dissolved substances and the state of the peatlands especially of their ditches. To research this hypothesis four test areas of different state were chosen. Their state and the output of DOC and other dissolved substances were investigated with methods from landscape ecology from 2001-2003. It was the first time, that peatlands in the “Erzgebirge Mountains” were investigated in such a way. The badest state had the test area where the ditches were cleaned in 2000/ 2001 (“Weiße Mulde”, Western “Erzgebirge Mountains”). This test area showed the lowest but constant DOC-concentrations and DOC-output during the investigation period. The test areas “Carlsfeld” and “Löffelsbach” (Western “Erzgebirge Mountains”) had the best state. The state of “Carlsfeld” is related to the narueal closed ditches, which cause the processes of self regeneration. Due to such processes the DOCconcentrations were distinctly higher but very variable in dependence on weather and runoff. The same was supposed to DOC-output. The same valuation got the test area “Löffelsbach”, because of rewetting by technical closed ditches in 2001. During the investigation period the highest DOC-concentrations of all test areas were measured there. Similar to “Carlsfeld” DOC-concentrations and –output were highly variable in dependence on weather and runoff. The state of the test area “Salzflüßchen” (Eastern “Erzgebirge Mountains”) is also related to processes of self regeneration but was valuated bader than “Carlsfeld”, because the effect of former drainage was stronger in this area. In 2005 the rewetting of the test area is planed by “Naturpark Erzgebirge/ Vogtland”. In the consequence the DOC-concentrations and –output will increase similar to “Löffelsbach”. The results of the investigations indicate that a connection exists between state of peatlands and output of dissolved substances esspecially DOC. The results are supported by national and international literature. It will be clear, that more research is necessary especially on the field of comparative investigations of peatlands with different states in the “Erzgebirge Mountains”.
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Pratte, Steve. "Les tourbières ombrotrophes en tant qu'archives de la variabilité des apports de poussières atmosphériques holocènes au Québec boréal - Implications paléoenvironnementales et paléoclimatiques." Thesis, Toulouse, INPT, 2016. http://www.theses.fr/2016INPT0044/document.
Full textAbstract:
Les poussières atmosphériques naturelles jouent un rôle complexe dans le système climatique global étant à la fois un facteur affectant le climat et variant en fonction de ce dernier. Notre compréhension des différentes interactions entre les poussières atmosphériques et le climat est limitée par l’importante variabilité spatiale et temporelle des celles-ci. À l’aide de tourbières ombrotrophes, la variabilité spatiale et temporelle des dépôts de poussières atmosphériques holocènes au Québec boréal fut caractérisée en lien avec les fluctuations climatiques. Les flux de poussières atmosphériques furent reconstruits à l’aide des concentrations en terres rares. Les isotopes du Nd et Pb en combinaison avec les terres rares ont été utilisés afin de déterminer la source des particules déposées dans les tourbières. Afin d’évaluer les liens entre les flux de poussières et la variabilité climatique, les changements temporels dans les flux de poussières et l’isotopie du Nd furent comparés à la taille des particules déposée et des reconstitutions écohydrologiques basées sur l’analyse des macrorestes végétaux et des thécamoebiens. Dans les deux premiers volets de l’étude, les flux de poussières atmosphériques furent reconstruits dans deux tourbières de la Côte-Nord alors que les particules déposées dans celles-ci furent caractérisées à l’aide des concentrations des terres rares (REE), des isotopes du néodyme et du plomb ainsi que la granulométrie. Les deux profils présentent des valeurs de Nd similaires, ce qui s’explique soit par une source commune des poussières atmosphériques ou encore des sources distinctes, mais possédant des valeurs de Nd similaires dans les deux régions. Les deux sites étudiés montrent des tendances différentes dans les flux de poussières. La tourbière IDH montre peu de variations dans les flux de poussières, ce qui s’explique en partie par l’emplacement du site d’étude, qui prévient les apports de poussières atmosphérique. La tourbière Baie quant à elle, montre deux périodes de flux de poussières plus élevés soit 1700-1000 et 650-100 cal a BP correspondant avec des périodes de refroidissement du climat documentées. Les REE, le Nd et les tailles de particules suggèrent qu’au cours des 2000 dernières années, la tourbières de Baie a reçu une proportion accrue de poussières atmosphériques provenant de sources locales. Ces deux périodes ont été identifiées comme des épisodes d’instabilité climatique en réponse à une instabilité hydroclimatique régionale et une plus grande variabilité des températures (principalement contrôlée par l’activité solaire). Un changement du régime des vents dans la région a aussi probablement influencé ces les variations observées. Dans le troisième chapitre, les mêmes analyses furent réalisées sur des carottes de tourbe d’une tourbières de la Baie James, La Grande 2 (LG2). Des apports accrus de poussières furent observés lors de différentes période : 4000 à 3000, 2600 à 2000, 1600 à 1000, 800 à 650 cal a BP et de 1960 à 1990AD. Au moins trois sources distinctes constituent les apports de poussières dans le temps: les sédiments marins à la base de la tourbières, la moraine de Sakami, deux sources locales, ainsi qu’une source probablement plus régionale dont l’origine est non-identifiée. La période allant de 7000 à 4100 cal a BP montre des valeurs près des sources locales (Nd : -36 à -29). Une augmentation graduelle des valeurs de Nd à partir de 4100 cal a BP suggère une diminution des apports locaux de poussière à la faveur d’une source non identifiée. La majorité des périodes d’apports accrus de poussières identifiées correspondent à des périodes documentées comme étant froides et sèches probablement lié à des intrusions de masses d’air arctiques. La présence de certains de ces pics de poussières lors de minimums solaires suggère que la variabilité solaire joue aussi un rôle dans la variabilité climatique de la régionMineral dust plays an important role in the global climate system having effects on the radiation budget and the chemical composition of the atmosphere. Our understanding of the exact role of dust in the Earth’s climate system is still poorly constrained mostly due to a lack of data reflecting the high spatial and temporal variability of dust. Using peat bogs, spatial and temporal variability of Holocene dust deposition in boreal Quebec was investigated in relation to climate fluctuations. Dust fluxes were reconstructed using rare earth elements (REE) concentrations in bulk peat, while Nd and Pb isotopes in combination with REE were used to identify the source of dust particles deposited into these bogs. In order to evaluate the relationship between dust fluxes and climate variability, temporal changes in dust flux, and Nd isotopes were compared to dust grain size and ecohydrological reconstructions derived from testate amoebae and plant macrofossils. In two peat bogs from the North Shore region of the St. Lawrence Estuary (Baie bog) and Gulf (IDH bog), atmospheric dust fluxes were reconstructed using REE concentration while the geochemical composition of deposited dust was characterized using Nd and Pb isotopes combined with REE and grain size. Both peat bogs present similar Nd values, which suggests either a common source or sources with similar signatures in both regions. In terms of dust flux, the two study sites display distinct tendencies. IDH bog show few variations in dust flux, which can be explained by its geographical setting, where a tree fringe and higher altitude likely partially prevent dust from reaching the peat bog. Two dust events were recorded in the Baie bog from 1750 to 1000 cal BP and 600 to 100 cal BP and correspond to documented cold periods. These two periods have been found to occur at the same time as periods of high variability in the macrofossil record (i.e. successive layers dominated by Sphagnum or Ericaceae). REE elements, Nd and grain-size distribution suggest that, over the last 2000 years, the Baie bog received more local dust. The two periods were identified as periods of increased local storminess in response to regional hydroclimatic instability and temperature variations mainly controlled by solar activity. These episodes of climatic instability could also have been caused by changes in the wind regime. The same set of analyses were performed in a third peatland located in the James Bay region, the La Grande 2 bog (LG2). Increases in dust flux were reconstructed from 4000-3000, 2600-2000, 1600-1000, 800-650 cal BP and from 1960-1990AD. The Nd values show a large variability from -37 to -12, identifying a least three sources: local marine sediment, the Sakami moraine and another unidentified source likely from a more regional origin. Between 7000 and 4100 cal BP, Nd values resemble those localsources (-36 to -29). A gradual increase in Nd signature is observed from 4100 to 1500 cal BP suggesting a decreasing influence of local sources in favor of a yet unidentified source. The occurrence of increased dust deposition during cold periods in two of the three studied bogs suggests that dust fluxes can be used as an indicator of cold and dry climatic conditions in boreal Quebec. In northeastern Canada, these cold and dry conditions are usually the results of the intrusion of Arctic air masses. The exact mechanism controlling these incursion is yet unknown, but the similar timing of solar minima and dust peaks suggest that solar irradiance may also have played a role. The fact that both Baie and LG2 sites display similar tendencies during the last 2000 years reveals that both regions were likely controlled by the same climatic processes
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Borgmark, Anders. "The colour of climate : A study of raised bogs in south-central Sweden." Doctoral thesis, Stockholm University, Department of Physical Geography and Quaternary Geology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-619.
Full textAbstract:
This thesis focuses on responses in raised bogs to changes in the effective humidity during the Holocene. Raised bogs are terrestrial deposits that can provide contiguous records of past climate changes. Information on and knowledge about past changes in climate is crucial for our understanding of natural climate variability. Analyses on different spatial and temporal scales have been conducted on a number of raised bogs in south-central Sweden in order to gain more knowledge about Holocene climate variability.
Peatlands are useful as palaeoenvironmental archives because they develop over the course of millennia and provide a multi-faceted contiguous outlook on the past. Peat humification, a proxy for bog surface wetness, has been used to reconstruct palaeoclimate. In addition measurements of carbon and nitrogen on sub-recent peat from two bogs have been performed. The chronologies have been constrained by AMS radiocarbon dates and tephrochronology and by SCPs for the sub-recent peat.
A comparison between a peat humification record from Värmland, south-central Sweden, and a dendrochronological record from Jämtland, north-central Sweden, indicates several synchronous changes between drier and wetter climate. This implies that changes in hydrology operate on a regional scale.
In a high resolution study of two bogs in Uppland, south-central Sweden, C, N and peat humification have been compared to bog water tables inferred from testate amoebae and with meteorological data covering the last 150 years. The results indicate that peat can be subjected to secondary decomposition, resulting in an apparent lead in peat humification and C/N compared to biological proxies and meteorological data.
Several periods of wetter conditions are indicated from the analysis of five peat sequences from three bogs in Värmland. Wetter conditions around especially c. 4500, 3500, 2800 and 1700-1000 cal yr BP can be correlated to several other climate records across the North Atlantic region and Scandinavia, indicating wetter and/or cooler climatic conditions at these times. Frequency analyses of two bogs indicate periodicities between 200 and 400 years that may be caused by cycles in solar activity.
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Kellner, Erik. "Surface Energy Exchange and Hydrology of a Poor Sphagnum Mire." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2001. http://publications.uu.se/theses/91-554-5121-7/.
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Whinam, Jennie. "A study of the ecology of Tasmanian sphagnum peatlands." Thesis, 1990. https://eprints.utas.edu.au/21934/1/whole_WhinamJennie1992_thesis.pdf.
Full textAbstract:
The ecology of Sphagnum peatlands in the southern hemisphere has been poorly
understood. Comparisons with northern hemisphere literature suggest that Tasmanian
Sphagnum peatlands are limited in their morphology and geomorphic expression,
possibly due to relatively low effective precipitation. While Sphagnum bogs tend to
occupy nutrient poor situations in the northern hemisphere, in Tasmania they do not
occur on the poorest substrates, despite climatic suitability.
To provide data on spatial variability of Tasmanian Sphagnum mires, a survey of 137
sites across Tasmania was carried out. Plant species composition and cover, peat
depths and height of hummocks were recorded. Climatic data were generated by using
the computing package BIOCLIM. Peats from a subset of samples were analysed for
their nutrient composition. Eight ecologically distinct groups spanning an almost
continuous gradient from high to low altitude sites were recognised. Floristic variation
between sites along this gradient can largely be explained by location along secondary
gradients of nutrient availability and disturbance (fire).
In a glasshouse experiment, the dry matter biomass of S. cristatum showed no
significant relative effects when subjected to drought, fertiliser or shade treatments,
either singularly or interactively. Shade resulted in a reduced biomass of Sphagnumassociates,
suggesting that shade affects the competitive ability of other species.
Monitoring of exclosure and control plots provided data which suggest that grazing
may result in the maintenance of conditions suitable for Sphagnum by altering interspecific
competition. The effects of grazing appear to be more pronounced at lower
altitude, high productivity sites than at higher altitudes. There was no evidence to
suggest that marsupials graze Sphagnum moss.
Monitoring of a site subjected to a low intensity burn provided some short-term data on
this disturbance event. Initial effects varied according to the vegetation present, which
influenced the local severity of the fire. The most significant change appears to be a
drying out of the peatland, which has resulted in a decline of Sphagnum.
Macrofossils from peat cores have enabled a possible model of Sphagnum peatland
succession in Tasmania to be developed. Succession appears to be multi-directional,
with micro-successional changes occurring across mires in response to extremely local
events. While the major successional pathway suggested by these cores is from
Sphagnum/Restiad to Sphagnum mires, progressfon to sites dominated by herbs and
shrubs is possible.
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Le, Roux Gaël [Verfasser]. "Fate of natural and anthropogenic particles in peat bogs / vorgelegt von Gaël Le Roux." 2005. http://d-nb.info/975224867/34.
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Frank, Jutta [Verfasser]. "Determination of arsenic and arsenic species in ombrotrophic peat bogs from Finland / vorgelegt von Jutta Frank." 2005. http://d-nb.info/977747735/34.
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JANÁK, Bohumil. "Revitalizace vybrané lokality rašeliniště s ukončenou těžbou." Master's thesis, 2017. http://www.nusl.cz/ntk/nusl-371713.
Full textAbstract:
Roast moorland one of the unique South Bohemian habitats. Currently, these sites are protected by law and they paid great attention to the media and professional - the general public. Local unique biodiversity is linked to hydrological conditions in the area, they live here rare species of animals and unique diverse plant communities. Despite this fact, a large part of the area previously used for peat extraction. These interventions, however, fundamentally not damage the local area and biological processes. That all changed beginning of the industrial peat extraction, where a large part of the territory forcibly drained, and cut down massively damaged by subsequent mining. Drainage of land degradation brought about significant changes in the local flor, faun and peat. After mining was part of the territory of unprofessional revitalized using improper procedures and are non-native plants such as: Giant cage and others. Since 1998 in this and surrounding areas held a program to rescue these unique habitats revitalization of Šumava wetlands and peatlands. Its main aim is to rescue the damaged wetlands and marshes, groundwater and increase the overall improvement of the water regime in the landscape. This program could involve the general public.
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LEŠTINOVÁ, Iveta. "Rašeliniště a jejich vliv na místní klima - Borkovická blata, Olešenský mokřad." Master's thesis, 2017. http://www.nusl.cz/ntk/nusl-320665.
Full textAbstract:
This diploma thesis discusses the influence of peat bog habitats on local climate, especially the temperature and humidity regime and indicators of energetic balance in similar locations Borkovice Marshland and Olešenský Wetland compared to the contrasting terrestric non-wetland TTP eco-system between the municipalities of Soběslav and Veselí nad Lužnicí. The evaluation was carried out based on the measurements of temperature and humidity characteristics in the given habitat with using automatic weather stations. The measuring was carried out in the period of 17 April until 3 November 2016 in an hour interval. During the vegetation period, samples of plant biomass were taken and species diversity of the observed ecosystems was described. The analysis of measured meteorological data has proved that the locations differed from each other. Results prove relatively small differences in air temperatures shot at the level of growth and in 2 meters above the surface. The greatest average temperatures were found in the location of the permanent grass growth. The greatest average pressure of water steam was noted in the location of Olešenský Wetland both in 2 meters above the suface and on the level growth. The lowest average saturation supplement was noted in the location of Olešenský Wetland, also it is the wettest place. The highest values were proved by the location of permanent grass growth, meaning that it is the driest place. The highest average evaporational fraction was noted in the location of Olešenský Wetland where a single vapour used the greatest amount of available energy. In the Borkovická Marshland lokality, a single vapour used the lowest amount of energy. Differences among the studied localities were caused by vegetation and the amount of water present in the eco-system.
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Bala, P. Ramya. "Evaluating Geochemical Proxies for Paleoclimate Reconstruction in Tropical Montane Peat : A Case Study from the Nilgiris, Southern India." Thesis, 2015. http://etd.iisc.ac.in/handle/2005/3537.
Full textAbstract:
Peat from the temperate regions has been used for paleoenvironmental reconstruction using diverse proxies for over a century now. Peat is rare and severely understudied in the tropics. The montane peat bogs of the Nilgiris, southern India have been found to preserve global climatic signals including the Holocene Optimum and the Last Glacial Maximum (LGM). At Sandynallah, one of the oldest peat accumulations in the world at >40 kyr BP, we had undertaken a high resolution paleoenvironmental reconstruction using multiple proxies which are yet to be evaluated in the tropical context. The study consists of 3 main objectives, i. Establishing an accurate high resolution chronology for the peat profile using radiocarbon dating, ii. Extracting vegetation and climate information from C/N ratio and Rock-Eval indices and iii. Using elemental profiles to establish the utility of inorganic geochemical proxies for processes such as weathering and dust transport. High resolution chronology for the site was built using Accelerator Mass Spectrometry (AMS) radiocarbon dates. To improve accuracy of the age-depth model, we also tested 4 samples for the effects of the AAA (Acid-Alkali-Acid) extraction method, the most common pre-treatment method for peat in the world. We compared ages on bulk samples (acid washed) and AAA treated samples from 4 different depths. We find that for all depths, the ages of the untreated samples do not lie within the internal uncertainty window and differ from the AAA treated sample age by at least an order of magnitude of the internal error, if not more. Based on these results we argue that the internal error should be used in conjunction with a reliable estimate of external error in an age-depth model for more realistic dating of paleoclimatic events. C/N ratios were explored for their paleoclimatic potential in conjunction with Rock-Eval indices and it was found that decomposition in tropical peat, as opposed to temperate peat, may not be sensitive to climatic perturbations. Inorganic geochemical proxies were also evaluated through this study. We see that the major and trace elements, except the lanthanide series do not show many significant trends for paleoenvironmental interpretation. But the lanthanides show some promise for identifying potential sources of dust and weathered material. Our study has addressed the gap in knowledge about the utility of recent geochemical proxies in tropical peat and has attempted to provide a solution to improve reliability in constructing age-depth models.
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Bala, P. Ramya. "Evaluating Geochemical Proxies for Paleoclimate Reconstruction in Tropical Montane Peat : A Case Study from the Nilgiris, Southern India." Thesis, 2015. http://etd.iisc.ernet.in/2005/3537.
Full textAbstract:
Peat from the temperate regions has been used for paleoenvironmental reconstruction using diverse proxies for over a century now. Peat is rare and severely understudied in the tropics. The montane peat bogs of the Nilgiris, southern India have been found to preserve global climatic signals including the Holocene Optimum and the Last Glacial Maximum (LGM). At Sandynallah, one of the oldest peat accumulations in the world at >40 kyr BP, we had undertaken a high resolution paleoenvironmental reconstruction using multiple proxies which are yet to be evaluated in the tropical context. The study consists of 3 main objectives, i. Establishing an accurate high resolution chronology for the peat profile using radiocarbon dating, ii. Extracting vegetation and climate information from C/N ratio and Rock-Eval indices and iii. Using elemental profiles to establish the utility of inorganic geochemical proxies for processes such as weathering and dust transport. High resolution chronology for the site was built using Accelerator Mass Spectrometry (AMS) radiocarbon dates. To improve accuracy of the age-depth model, we also tested 4 samples for the effects of the AAA (Acid-Alkali-Acid) extraction method, the most common pre-treatment method for peat in the world. We compared ages on bulk samples (acid washed) and AAA treated samples from 4 different depths. We find that for all depths, the ages of the untreated samples do not lie within the internal uncertainty window and differ from the AAA treated sample age by at least an order of magnitude of the internal error, if not more. Based on these results we argue that the internal error should be used in conjunction with a reliable estimate of external error in an age-depth model for more realistic dating of paleoclimatic events. C/N ratios were explored for their paleoclimatic potential in conjunction with Rock-Eval indices and it was found that decomposition in tropical peat, as opposed to temperate peat, may not be sensitive to climatic perturbations. Inorganic geochemical proxies were also evaluated through this study. We see that the major and trace elements, except the lanthanide series do not show many significant trends for paleoenvironmental interpretation. But the lanthanides show some promise for identifying potential sources of dust and weathered material. Our study has addressed the gap in knowledge about the utility of recent geochemical proxies in tropical peat and has attempted to provide a solution to improve reliability in constructing age-depth models.
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Doležal, Tomáš. "Posouzení vlivu revitalizačních opatření vybraných horských vrchovišť v povodí horní Vydry na jejich vodní režim." Master's thesis, 2015. http://www.nusl.cz/ntk/nusl-334675.
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Assessment the effect of revitalizing measures of chosen peat bogs in the upper Vydra River basin on their water regime Abstract: Despite a number of research projects, the influence of peat bogs on the hydrological regime remains a largely unexplored topic. In the past, several peat bogs in the Šumava National Park were exposed to a very strong anthropogenic pressure. Subsequently, revitalizing measures were applied to mitigate the impact of human interventions, to stop the degradation of these precious habitats, and to reform the disturbed peat bog water regime. This thesis is focused especially on fluctuations of water table level and on the hydrological regime in the catchments of Rokytka and Cikánský Brooks. Thesis further develops the topic solved in author's bachelor thesis called "Peat bog revitalizing measures and their effect on runoff dynamics in the Otava River headstream area." It contains experimental research of the influence of drainage canals and revitalizing measures on water table fluctuation. It also aims to identify the extent to which meteorological factors contribute to changes in groundwater level and to assess the present state of revitalization measures and their influence on the runoff regime. Key words: peat bogs, revitalizing measures, Šumava Mountains, water regime
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Fialová, Markéta. "Ekologický pohled na morfologii rozsivek." Master's thesis, 2013. http://www.nusl.cz/ntk/nusl-321118.
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A traditional species concept of diatoms is based on morphological characters of their siliceous boxes. A multidisciplinary approach to defining species of diatoms has revealed the hidden diversity within the traditionally defined species. But the newly recognized species are morphological variable and indistinguishable by the naked eye. Recent studies showed that different morphotypes show different ecological preferences. This master thesis focuses on the morphology of natural populations of the diatom species complex Frustulia rhomboides which contains both the traditional and the cryptic species, and it engages how the morphology reflects the effects of environmental conditions. Landmark methods of geometric morphometrics were used in order to analyze the morphological variability of diatom frustules of this species complex within various peat bog habitats in the Czech Republic. Selected environmental parameters were measured and the species composition of diatom communities present in the samples was investigated. These data were used to analyze the relationship between the environmental conditions and the cell shape variability within the complex. The analysis revealed the main trends of morphological variability related to different environmental conditions. Two morphotypes characteristic...
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DUTKA, Ladislav. "Vývoj a perspektivy návštěvnosti Chalupské a Jezerní slatě (NP Šumava)." Master's thesis, 2013. http://www.nusl.cz/ntk/nusl-154475.
Full textAbstract:
Peat bogs of the Šumava National Park are very valuable biotopes with an occurrence of the specific flora and fauna, including glacial relicts. These localities are also very attractive for tourists, so it is important to find the reasonable compromise between an attendance and a nature protection. The study is dealing with the development of touristic attendance of two peat bogs from 2010 to 2012 and enlarges my bachelor?s work (Comparison of attendance of two peat bogs (Chalupská a Jezerní slať) in Šumava National Park). The work is divided into two parts. The first, theoretical part, includes a literary review about the character of the Šumava?s peat bogs and the tourism in those localities. A practical part monitors the attendance of the peat bogs and analyses the research via questionnaire, focused on the specifics of the tourists, their priorities during visit of the peat bogs and transport to those localities. The research was connected to bachelor?s work ? there were also 5 terms of field monitoring, the dates in 2012 were close to the dates in 2010 and the number of the panelled questionnaires was the same, 200. So the results of both years could be easily compared. It was found that the number of peat bogs? visitors increases. There were 1438 visitors on Jezerní slať and 1106 on Chalupská slat peat bog. Jezerní slať was more visited than Chalupská slať in both 2010 and 2012. Most of the visitors came by bicycle, but the number of visitors who came by bus was increased. Huge increase was found in number of dogs, which was really surprising. The visitors of Jezerní slať more often stayed in camping sites than in 2010. The problem of possible development and perspectives of investigated peat bogs is also outlined in the end of the work.
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Svoboda, Pavel. "Rozšíření, diverzita a ekologie bentických krásivek na lokálním prostorovém měřítku." Master's thesis, 2012. http://www.nusl.cz/ntk/nusl-309662.
Full textAbstract:
Besides spatial heterogeneity, an important component of diversity of the protist communities is also the variation in species assemblages through time (temporal turnover). Spatial and temporal variation in patterns of distribution and abundance of lentic microphytobenthos assemblages is often large and occurs at relatively small spatial scale. Desmids (Zygnematophyceae) often constitute a characteristic part of the microphytobenthos of peat bogs. Despite their important role in primary production and fact that they are useful indicators of ecosystem uniqueness, investigations of their seasonality and spatial distribution are scarce. In my thesis I have investigated if desmid epipelic communities are driven rather by neutral or niche-based processes, and I also focused on the factors affecting their diversity, seasonal dynamics and spatial patterns at the local spatial scale. The study was conducted at the two different types of biotopes - minerotrophic lowland peat bogs (Doksy region) and ombrotrophic raised bogs (Jizera Mountains region). Seasonal changes in species composition and diversity of assemblages were not evident. This may be affected by a monopolization effect and also that local abundance of species was positively correlated with population persistence, which suggests that high local...
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Kocum, Jan. "Tvorba odtoku a jeho dynamika v pramenné oblasti Otavy." Doctoral thesis, 2012. http://www.nusl.cz/ntk/nusl-305924.
Full textAbstract:
In context of catastrophic floods and extreme droughts in recent years there is an urgent need of solving of issues dealing with protection against hydrological extremes, not using just classical engineering methods but also untraditional practices. There is a new protection strategy focusing on gradual increase of river catchment retention capacity including its headwater regions. All of the issues related to various possibilities and measures leading to river headstream areas retention capacity increase should be discussed by experts in various fields taking into account objectives and priorities of a supra-regional, regional and local significance. Natural runoff process is affected by man already by its birth, thus in headwaters where numerous procedures related to runoff retardation and water retention increase in headstream areas could be realized. Suitable conditions for the research realization at present is related to the Otava River headwaters (sw. Czechia) representing the core zone of a number of extreme runoff events and with high heterogeneity in the terms of physical-geographic and socio-economic aspects. To understand and clarify the runoff generation process and the effect of various physical-geographic factors on its dynamics, the detailed analyses of runoff regime in chosen...