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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Vatten och deponeringar : Vatten som aktörskap vid val av deponering / Water and depositions : Waters agency in choosing places of depositions

Sandberg, Nathalie January 2023 (has links)
Deponeringar under bronsåldern är ett fenomen som uppstod både på land och i olika formerav vattentillstånd som till exempel sjöar, våtmarker, floder och vattenfall. Mycket forskninghar gjorts inom det här området, kring vilka typer av fynd och föremål som har hittats i dessasammanhang och många frågor uppstår när man arbetar med deponeringar som ett fenomen.Vad var anledningarna till deponering, vad var orsaken till varför de har placerats där ochhade omgivningen någon betydelse för människorna som deponerade människor vid dessaplatser. Frågorna som ställs inför den här studien kommer att vara för att se om vattnet hadesin egna aktörskap som spelade roll, om platsen, såsom rinnande eller stillastående vattenhade en påverkan, om det fanns andra faktorer eller krafter bakom valet av plats fördeponering. Denna artikel syftar till att diskutera vatten med sin egna form av akens och hurdetta relaterar till varför deponeringar skedde från första början i Mälardalsområdet. / Bronze age depositions was a phenomenon that occured both on land and in different forms ofwatery places such as lakes, bogs, rivers and waterfalls. A lot of research has been done inthis area, around what kinds of finds and objects have been found in these contexts and manyquestions arise while working with depositions as a phenomena. As to why they have beenput there, what were the reasons behind the depositioning and did the surrounding area matterto the people putting their own and other people down in these watery places. The questionsfor this study will be if the waters had its own agential power that played a part, whether theplace, such as flowing or stationary water had an impact or if there were other factors orpowers behind the choosing of place to deposition. This paper aims to discuss water with itsown form of agency and how this relates to why depositions took place in the first place inMälardalen.
42

The hydrology and dissolved organic carbon (DOC) biogeochemistry in a boreal peatland /

Fraser, Colin J. D. January 1999 (has links)
No description available.
43

Colonization of restored peatlands by insects : Diptera assemblages in mined and restored bogs in eastern Canada

Grégoire Taillefer, Amélie. January 2007 (has links)
No description available.
44

Carbon biogeochemistry of open water pools on an ombrotrophic raised bog, James Bay, Québec, Canada

McEnroe, Nicola A., 1973- January 2008 (has links)
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.
45

Carbon biogeochemistry of open water pools on an ombrotrophic raised bog, James Bay, Québec, Canada

McEnroe, Nicola A., 1973- January 2008 (has links)
No description available.
46

Hochmoore im Erzgebirge - Untersuchungen zum Zustand und Stoffaustragsverhalten unterschiedlich degradierter Flächen / Peat bogs in the mountains "Erzgebirge" - investigations of state and output of dissolved substances from differently degraded areas

Böhm, Anna Katharina 14 December 2006 (has links) (PDF)
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”.
47

Vývoj a perspektivy návštěvnosti Chalupské a Jezerní slatě (NP Šumava) / Development end perspectives of attendance of two peat bogs (Chalupská a Jezerní slať) in Šumava National Park

DUTKA, Ladislav January 2013 (has links)
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.
48

Mysterier från mossen : Mosslik från Danmarks järnålder och deras relevans idag / Mysteries from the Bog : Bog Bodies from Denmark and their Relevance Today

Frank, Martin January 2023 (has links)
Den här texten fokuserar på fem mossliksfynd från förromersk järnålder i Danmark. Med dessa fallexempel undersöktes också vilken betydelse mossen som en våtmark i sig kan överbevarandet av forntida människokroppar och vilka forskningsresultat som presenterats underde senaste åren. Utifrån dessa avgränsningar ämnade frågeställningarna att jämföra de fem fynden, undersöka möjliga orsaker till varför offren dött samt vilka möjligheter och begränsningar som fyndmaterialet har idag. Tanken kring teori var att se hur mossar kunde fungera som speciella platser under järnålder för mänskliga handlingar av deponeringar. Resultatet blev att där finns likheter och skillnader mellan mossliken, att en mängd orsaker kunde förklara deponeringar i mossar, och att där finns både positiva möjligheter med fortsatt forskning men att fyndmaterialet också är begränsat på flera sätt. / This paper focuses on five bog bodies from Denmark, from the pre-roman Iron Age. With these case examples, the importance of the bog as a wetland in itself in preserving ancient human bodies was also investigated and which research results have been presented in recent years. Based on these boundaries, the question intended were to compare the five case examples, investigate possible reasons for why the victims died and what opportunities and limitations the find material has today. The idea behind the theory was to see how bogs could have functioned as special sites for human depositions during the Iron Age. The results were that there are similarities and differences between bog bodies, that a number of reasons could explain depositions, that there are both positive opportunities with continued research but that the material found is also limited in several ways.
49

A Delayed Climatic Response to Solar Forcing at 2800 cal. BP: Multi-Proxy Evidence from Three Irish Peatlands

Swindles, Graeme T., Plunkett, G., Roe, H.M. January 2007 (has links)
No / Multiproxy palaeohydrological records from three raised bogs in Northern Ireland indicate that a major shift to wetter/cooler climatic conditions postdated the rapid decrease in solar activity at 2800 cal. BP by ~100 years. This event is bracketed by two wiggle-match radiocarbon-dated cryptotephra layers in each profile, enabling a high degree of chronological precision. These replicated data corroborate previous findings based on Irish peat humification profiles, and may indicate spatial complexity in the climatic response to solar activity between oceanic and continental areas.
50

Rozšíření, diverzita a ekologie bentických krásivek na lokálním prostorovém měřítku / Distribution, diversity and ecology of benthic desmids along local spatial scale

Svoboda, Pavel January 2012 (has links)
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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