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The climate of the Earth is expected to warm due to increasing atmospheric concentrations of greenhouse gases, particularly carbon dioxide (CO 2). The impact of this change on terrestrial ecosystems is uncertain, yet these ecosystems contain three times more carbon (C) than the atmosphere and could considerably augment anthropogenic CO2 emissions. This thesis aimed to quantify the terrestrial C stored in an area of Pennine moorland and predict its response to changes in climate and management. The area of soil and vegetation types was determined using existing maps of the study site and a geographical information system. Vegetation C was assessed using results from published productivity studies, and soil C was evaluated from a programme of field sampling. Most C was contained in peat soils and comparison of the results with the UK's national C inventory identified inaccuracies in the national values. The impact of sheep grazing and moorland burning on C storage was investigated by utilising long-term experiments at the site. Areas where sheep had been excluded for forty years were compared to grazed areas and burning was investigated using a randomised block experiment. Grazing had little impact on terrestrial C storage, but regular burning significantly reduced C sequestration in peats. The response of the C store to climate change was investigated by i) determining the impact of past climate on C storage and ii) developing a predictive model by measuring the underlying processes of C input and output in the ecosystem. Both approaches illustrated the sensitivity of the ecosystems C balance to climate, suggesting that global warming will reduce C accumulation at the site and, therefore, augment atmospheric CO 2 concentrations. The novel use of near infrared reflectance spectroscopy to characterise peat samples was also demonstrated, indicating opportunities for application of this technique in palaeoecological studies of peats.

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Thesis (Ph. D.)--University of Florida, 1982. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 92-95).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1975. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 174-187).

Made available in DSpace on 2014-06-11T19:35:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-07-13Bitstream added on 2014-06-13T20:06:25Z : No. of bitstreams: 1 cunha_bb_dr_araiq.pdf: 1936730 bytes, checksum: d91b81f827ca80fb65e25addc6094ad9 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / As interações entre interferentes endócrinos (IE), bisfenol A, estrona, 17β- estradiol, e amostras de sedimentos e turfas tropicais foram estudadas em diferentes condições de pH, tempo e quantidade de amostra, bem como estudos de sorção e dessorção utilizando colunas recheadas com turfas. Ainda foram realizados experimentos de fitorremediação de bisfenol A, linuron e 17α- etinilestradiol de diferentes ambientes utilizando as espécies Lolium perenne e Raphanus sativus. Os dados obtidos a partir dos experimentos com sedimentos mostraram uma melhor interação IE-sedimento ocorreu em valores menores de pH, enquanto os com turfas foram observados em pH 6. Uma cinética lenta foi observada através do modelo cinético de pseudo-segunda ordem que descreveu bem as interações dos IE com sedimentos e turfas (r> 0,99). A partir das isotermas de Langmuir e Freundlich, os valores dos coeficientes n e b, revelaram que as interações IE-turfa são reversíveis, exceto nos experimentos realizados com a amostra coletada em Santo Amaro das Brotas e estrona e 17α-etinilestradiol, onde os valores de b foram, respectivamente, 1,50 e 13,94. Os resultados de sorção em coluna mostraram que as turfas podem ser utilizadas como alternativa para a remoção destes compostos dos sistemas aquáticos onde tanto a sorção quanto a dessorção foram superiores a 75 %. Os experimentos de fitorremediação mostraram que a espécie Raphanus sativus foi mais eficiente na remoção dos IE, principalmente em valores de concentração dos IE mais baixos, a germinação das duas espécies foram menores quando utilizada a água do rio Morelli como meio. Estudos desta natureza proporcionam uma melhor compreensão da mobilidade, transporte e/ou reatividade destes contaminantes em sistemas aquáticos, onde a disponibilidade dos IE pode estar relacionada com a presença de... / Interactions between endocrine disruptors (ED), bisphenol A, estrone, 17β- estradiol, and samples of sediments and tropical peat were studied under different conditions of pH, time and amount of samples, and sorption and desorption studies using packed columns with peat. Although, experiments of phytoremediation of bisphenol A, 17α-ethinylestradiol and linuron were conducted in different environments using Lolium perenne and Raphanus sativus species. Data obtained from the experiments showed a better EDsediment interactions at pH 3, however a better ED-peat interactions was observed at pH 6. Slow kinetics was observed by the kinetic model of pseudosecond order which described well the interactions between IE and sediments and peat samples (r> 0.99). From the Langmuir and Freundlich isotherms, the coefficients n and b values, revealed that the ED-peat interactions are reversible, except in experiments with the sample collected in Santo Amaro das Brotas and estrone and 17α-ethinylestradiol, where the values of b were respectively 1.50 and 13.94. The column sorption results showed that peat may be used as an alternative for the removal of these compounds from aquatic systems where sorption and desorption was higher than 75%. The phytoremediation experiments showed that Raphanus sativus specie was more efficient in the removal of ED, especially in lower concentrations of ED. Lower germination of both species were observed in all experiments with water from Morelli river. Studies of this nature provide a better understanding of mobility, routing and / or reactivity of these contaminants in aquatic systems, where the availability of ED can be related to the presence of organic material. And still shows that both peat and phytoremediation, natural and economically attractive methods, can be... (Complete abstract click electronic access below)

A history of vegetation and climate change during the last two millennia is elucidated from ombrogenous blanket peat sequences from the central and eastern North York Moors. The evidence is derived from five mires Harwood Dale Bog, May Moss, Fen Bogs, Yarlsey Moss and Bluewath Beck. May Moss received particular attention because it is the only remaining unmodified blanket mire on the North York Moors. All the sites were cored, with May Moss yielding seven cores, four of which were extruded along a five metres transect. The cores were selectively analysed for plant macrofossil, testate amoebae, humification and pollen. Chronologies were constructed using 14C dating and the judicious use of biostratigraphic marker horizons. Comparison of 14C dates obtained on bulk peat samples and on pure Sphagnum remains encountered substantial differences, which raises anxieties about 14C dating of a material as heterogeneous as peat. The regional vegetation history elucidated from the pollen evidence reflects changes in the demography, culture, economy and climate of the North York Moors. Evidence of woodland decline and abundant agricultural taxa are attributed to phases of increased agricultural exploitation of the uplands in response to a commercial approach to farming during the Romano-British period, population expansion during the Anglo-Scandinavian period, and attempts to exploit the moorlands during the boom periods of the 12th-13th and 15th-16th centuries. Conversely, phases of woodland expansion and agricultural decline are associated with the Roman withdrawal from England, the 'harrying of the north' in AD 1069-70 and demographic collapse during the 14th century. T estate amoebae, plant macrofossil and humification stratigraphies provide a record of mire palaeohydrology, which is used to infer a history of effective precipitation. There is a broad consistency within the palaeohydrological indications from a single core, which indicates that the techniques support each other. Furthermore, similar testate amoebae, plant macrofossil and humification stratigraphies were encountered in adjacent cores at May Moss. There is evidence of pronounced shifts to wetter/cooler conditions circa 500 BC, AD 450, 850, 1400, 1625 and 1825 separated by unambiguously drier/warmer phases circa AD 200-450, 700-800, 1100-1200, 1550-1600 and 1750-1800. The palaeoclimate time series displays a strong correlation with the record of solar variability; however, biosphere, atmosphere and oceanic interactions in the North Atlantic region and global volcanism also affect regional climate.

The main objective of this thesis was to determine how and why peat fails with the aim of reducing the threat caused by this and also for prevention of the occurrence. Peat is a very common soil in both the UK and Ireland so knowing how it fails and how to prevent it is hugely beneficial. To do this three seperate case studies where analysised, all located in Ireland but in different areas, to see if the failure methods had any similarities or differences that could be linked together. The main finding was that therewas not one sole causal factor for all peat slides but instead a combination of different factors; although some factors are more influential than others for example rainfall. A number of solutions where put forward such as a drainage system for the peat slopes and while they are limited, due to most of the factors being of natural origin, they have the potential to reduce the likelihood and frequnecy of failures if properly implemented.

Peat from a treeless "barrens" of the forest-tundra transition has been studied by the method or pollen analysis. The frequencies of various fossil pollens at successively greater depths of the peat deposits have been determined and presented in pollen diagrams, whose use is discussed in the study or the characteristics, vegetational history and development of the terrain. Illustrated with photographs of the terrain and photomicrographs of microfossils. / Thesis / Master of Arts (MA)

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