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Assessments of human land use, erosion, and sediment deposition in the Southeastern Australian TablelandsPortenga, Eric W. January 2015 (has links)
Humans have interacted with their surroundings for over one million years, and researchers have only recently been able to assess the geomorphic impacts indigenous peoples had on their landscapes prior to the onset of European colonialism. The history of human occupation of Australia is noteworthy in that Aboriginal Australians arrived ~50 ka and remained relatively isolated from the rest of the world until the AD 1788 when Europeans established a permanent settlement in Sydney, New South Wales. The southeastern Australian Tablelands landscape, west of Sydney, has seemingly undergone drastic geomorphic change since European arrival. The introduction of European grazing practices reportedly led to the occurrence of deep erosional incisions, gullies, into valley bottoms and hillslopes, releasing sediment, which is subsequently deposited over downstream wetland environments – swampy meadows. This sediment is often called post-settlement alluvium (PSA); however, the age and genesis of PSA in Australia are debated. Questions regarding the geomorphic features and processes in the Tablelands remain unanswered because few studies quantify the timing of gully incision, PSA deposition, or the pre-human rate of landscape change. Erosion rates inferred from concentrations of in situ 10Be measured in fluvial sediment (n = 11) and bedrock outcrops (n = 6) range from 2.9–11.9 mm/kyr and 5.2–13.8 mm/kyr, respectively. The two sample populations are statistically indistinguishable, suggesting no relief has been generated since 600–110 ka. The overall erosion rate in the Tablelands is 7.5 mm/kyr, equal to long-term denudation rates integrated since ~20 Ma. Aboriginal Australians have been present in the Tablelands for at least 30 kyr, ~12–26% of the cosmogenic integration time, yet widespread Aboriginal fire use did not measurably affect landscape erosion until ~5.5 ka, in sync with increased charcoal in the sediment record. Portable optically stimulated luminescence (OSL) reader data from poly-mineral and poly-grain size samples collected from gully wall profiles of PSA and swampy meadow sediment show that swampy meadow environments were buried by PSA and that PSA is alluvium derived from upstream gully erosion. No relationships between bulk OSL and sample grain size or mineralogy exist, and inferences about bulk sediment mineralogy or grain size cannot be determined from portable OSL reader data. Large variability in adjacent PSA sample replicates, however, reveals incomplete sediment bleaching conditions during PSA deposition during floods. Greater bleaching efficiency is inferred from the small variability of bulk OSL data in the uppermost 10s of cm of PSA profiles. Measured concentrations of meteoric 10Be and bulk OSL in two PSA deposits in Birchams Creek show that initial gully incision eroded into weathered sandstone regolith and not swampy meadow environments, as previously believed. Initial gully incision was shallow (<15 cm) and PSA filled ponds in the lower reaches of the catchment. Continued erosion upstream led to a second depositional episode of PSA before headward gully incision from the mouth of Birchams Creek eroded through PSA deposits. Headward erosion of this gully created the continuous gully present at the site today. Initial gully incision was likely the result of livestock trampling in valley bottoms during droughts, creating localised slopes greater than the critical slope threshold required to erode the valley bottom. OSL burial ages of six PSA deposits collected throughout the Tablelands range from 195.1 ± 17.8 to 90.4 ± 8.9 a, corresponding to AD 1800–1932. The OSL burial ages are younger than European arrival in the Tablelands, and the term, PSA, is redefined as post-European settlement alluvium in Australia, recognising the earlier settlement of the region by Aboriginal Australians whose land use did not lead to PSA deposition. PSA burial ages agree with existing quantitative and anecdotal gully incision data. Contrary to previous assertions that gully incision began asynchronously in the Tablelands, three periods of synchronous gully erosion in localised areas within the Tablelands are recognized: 185 a, 158 a, and 94 a (AD 1828, 1855, and 1919, respectively) – in the southern, northern, and central Goulburn Plains, respectively. The AD 1828 and AD 1919 periods of gully incision correspond to the transition from drought-dominated climate regimes to flood-dominated regimes, and the AD 1855 period of gullying corresponds to a flood-dominated regime. Gully incision in the Tablelands is thus a result of European-introduced grazing practices, which primed the landscape for further erosion and degradation during climatic shifts. PSA deposits in the southeastern Australian Tablelands are some of the most recent examples of anthropogenic sedimentation in human history. The earliest preserved examples of PSA-type sediments are ~8,000 years old and found throughout the world. The establishment of an onset date for the Anthropocene is currently debated, and I believe the oldest PSA and PSA-type sediments around the world can define this modern epoch.
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Sediment transport processes and coastal management of mixed sand and gravel beachesYu, Xiao Wei January 2009 (has links)
Mixed sand and gravel beaches are an important means of sea defence. The majority of beaches in the south coast of the UK are of the mixed type and beach replenishment is generally needed in order to maintain the effectiveness of these beaches against storm wave attacks. Despite vigorous research efforts in recent years, coastal engineers still do not have a reliable method to estimate the sediment budget in their designs. In addition, there is also a lack of understanding of the impacts of beach maintenance activities, such as recycling and re-profiling, on the performance of the beach and on the economics in maintaining the beach system. This thesis is mainly focused on establishing the relationships between sediment transport of a mixed beach and the wave climate, and between the beach performance and beach maintenance activities. The thesis also aims to establish essential considerations coastal engineers need to give when planning beach maintenance operations.
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Hydrogeological characterisation of the Chalk : with specific reference to unsaturated zone behaviourMolyneux, Ian January 2012 (has links)
Groundwater from the (largely unconfined) Chalk aquifer constitutes a major water resource. The unsaturated zone plays a crucial role in the hydrological cycle, determining the timing and magnitude of recharge, and the transport and fate of nutrients. However, despite over 30 years of study our understanding of this system is incomplete. The objectives of this research were to investigate the aquifer characteristics of the Chalk and to clarify the physical processes controlling the movement of water in the unsaturated zone. Combining results from laboratory tests, geophysical logs, CCTV surveys and field instrumentation comprehensive insights into unsaturated zone processes are provided. Stratigraphical and geographical distributions of aquifer properties were investigated and marl horizons shown to provide the principal contrasts in hydraulic conductivity. Results from novel testing procedures allowed the Chalk soil moisture characteristic to be quantified and suggested surface storage and film flow to be significant unsaturated zone processes. CCTV and geophysical surveys provided supporting evidence of this and also highlighted the role of marl horizons in controlling saturated and unsaturated flow. Geophysical surveys also showed that the Chalk lithostratigraphy can be related to physical characteristics and fracturing which act to control recharge processes. Recharge was studied at two instrumented sites allowing matric potential to be monitored beyond depths previously attempted. At East IIsley, Berkshire, UK, recharge occurred throughout the year via the matrix, contrastingly, at North Heath Barn, Sussex, UK, the capacity for vertical drainage was low and evidence suggested that episodic lateral fracture flow would occur instead of vertical recharge. The instrumentation also showed that the water level in an unlined observation borehole can be influenced by processes in the unsaturated zone and may be an unreliable indicator of the water table. The findings of this study have important implications for the representation of recharge in groundwater models and the reliability of the parameterisation and predictions of these models. The presence of stratigraphically constrained recharge pathways suggests focused recharge to be a significant, although poorly understood, process controlling recharge to the Chalk.
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Vegetation sensitivity to droughts (1982-2011) through remote sensing in the Yucatan Peninsula, MexicoDe la Barreda Bautista, Betsabe January 2017 (has links)
Ecosystems undergo permanent alteration and degradation as a result of the pressure exerted upon them by anthropogenic activities and natural causes. Amongst the natural causes, drought can have considerable impacts on vegetation productivity; these impacts include biomass reduction and changes in vegetation cycles, growth, and vitality. Such impacts have important implications for society, and understanding the impacts of drought in natural systems will help minimise vulnerability to it. The Yucatan Peninsula is a vulnerable area in climate change scenarios, where increased intensity and frequency of droughts is already occurring. This thesis aims to analyse how droughts impact upon vegetation on the Yucatan Peninsula, Mexico using both remotely sensed data (in particular the Advanced Very High Resolution Radiometer – AVHRR - data) and meteorological data (in situ precipitation data). Three major elements are addressed: (1) spatial and temporal precipitation variability, and the occurrence of droughts during the period 1980-2011; (2) vegetation productivity trends, focusing on the persistence and resilience of the different vegetation types present across the Yucatan Peninsula using remotely sensed data sets, specifically, the Normalised Difference Vegetation Index (NDVI) from the National Oceanic and Atmosphere Administration Advanced Very High Resolution Radiometer (NOAA-AVHRR) as a proxy for productivity in the period 1982 to 2011; and (3) the relationship between vegetation productivity and rainfall and the lack of it (i.e. droughts) at a more detailed temporal scale (monthly) with two vegetation indices (NDVI from AVHRR and MTCI from the MEdium Resolution Imaging Spectrometer (MERIS)). The main findings indicate that precipitation in the area follows a gradient from north to south which is linked to vegetation types in the area, from deciduous forest to evergreen forest. NDVI trends in the Yucatan Peninsula are generally stable during the period 1980-2011; however, negative trends are persistent in areas where human impacts and intensive agriculture are present. Analysis of resilience also shows that deciduous forest and grasslands are much less resilient to disturbance and have a longer recovery period compared to other vegetation types. Per-pixel regression analysis between precipitation and vegetation productivity shows high explained variances between NDVI and rainfall with a time-lag of 1 and 2 months and tropical dry forest is the biome most affected by droughts. These results are valuable for decreasing the vulnerability of the Yucatan Peninsula and they could be used for increasing the understanding of the area and therefore go further in the creation of warning and management programmes.
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Supporting local flood risk decision-making using participatory modellingMaskrey, Shaun Andrew January 2017 (has links)
Flood risk management is increasingly seeking to involve local stakeholders in decision-making, both to harness and benefit from their tacit knowledge and to devolve responsibility for delivering local-scale, individual and community responses. Current techniques used in flood risk management centre on a techno-scientific approach, which is well-suited to appraising and modelling hazard, but often inaccessible to those without specialist, technical expertise. This leads to participation that is often limited to infrequent consultation periods, keeping local stakeholders at the periphery of the decision-making process. Their absence from the more technical elements of the process can leave local stakeholders struggling to understand how different options have been identified, appraised and/or prioritised. This can in turn lead to dissatisfaction with process outcomes, lack of support for selected options, and foster distrust in expert practitioners. This thesis explores how participatory modelling techniques could complement current approaches, facilitating the co-production of models with local stakeholders that explore social constructions of risk, and the vulnerability of different receptors. It identifies the qualities that are sought from participation, including the need to remain highly accessible, yet sufficiently robust to capture the complexities encountered when working at the interface of social and physical systems. Reporting on two UK case studies, it exemplifies the benefits that two popular techniques, Bayesian networks and system dynamics, can deliver at different stages in the flood risk decision-making process. In each case, the effectiveness of the participatory approach is assessed using an evaluative framework that advances current approaches by including an early assessment of context, as well as a detailed exploration of substantive (user-defined goals), and social change outcomes. The holistic nature of the evaluation framework, and its population with practical criteria bespoke to flood risk management, enhance its transferability between different contexts. The thesis finds that participatory modelling techniques support the collating of diffuse tacit knowledge, building of consensus, strengthening of social networks, and the empowerment of local citizens to become volunteer risk managers; provided that process managers are willing to simplify the techniques to maintain accessibility, and be open to different metrics of success.
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Zoneamento geoambiental como subsídio aos projetos de reforma agrária. Estudo de caso: assentamento rural Pirituba II (SP)Shimbo, Julia Zanin [UNESP] 09 September 2006 (has links) (PDF)
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shimbo_jz_me_rcla.pdf: 4938318 bytes, checksum: f2c471db5c5cb971b7e38bb653a40aba (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Os projetos de reforma agrária apresentam dificuldades de planejamento para uso e ocupação da terra. Esses problemas afetam a qualidade de vida das famílias, a produtividade e a sustentabilidade ambiental. Isso se deve à carência de estudos interdisciplinares detalhados de diagnósticos e zoneamentos ambientais para implantação, desenvolvimento e gestão desses assentamentos. Assim, o objetivo principal desse estudo é estabelecer o zoneamento geoambiental no assentamento rural Pirituba II (Itapeva/Itaberá/SP) e analisar o uso desse instrumento para melhorar os projetos de reforma agrária que visem a sustentabilidade socioambiental. Para isso, foram realizadas fotointerpretação de fotos aéreas (escala 1:25.000) e verificações em campo para detalhar as informações ambientais básicas de drenagem, geologia estrutural, de unidades fisiográficas, e pedológicas. Essas informações permitiram a compreensão da evolução e dinâmica da paisagem. A partir da caracterização das unidades fisiográficas colúvio-aluvionares da área foram estabelecidos os fatores e processos endógenos e exógenos que resultaram na formação das paisagens. Isto permitiu estabelecer as zonas geoambientais (unidades aloestratigráficas). Essas foram divididas em subzonas geoambientais pela análise estrutural e fisiográfica, para posteriormente determinar as potencialidades e limitações de tais unidades. Dessa forma, mapas temáticos foram elaborados quanto à: suscetibilidade à erosão, indicação de áreas para proteção ambiental e adequação a culturas anuais. A aplicação do zoneamento geoambiental no assentamento Pirituba II forneceu um estudo detalhado e integrado do meio físico para planejamento local visando a sustentabilidade socioambiental. Portanto, esse zoneamento pode ser uma ferramenta útil para a gestão territorial e melhoria dos projetos de reforma agrária. / The environmental diagnostic studies that aim planning for land reform settlements are few and still present some gaps. These affect the life quality of families, productivity and environmental sustentability. Geoenvironmental zoning is based on the integration of physical aspects, and for this reason it may contribute with information that will be used for the environmental analysis of these settlements. The aim of the present study is to evaluate the geoenvironmental zoning applied to the Pirituba II Settlement (Itapeva/Itaberá/SP) as a reliable tool and instrument for the definition of lines that can help in the sustainable implementation of land reform projects, as much by the social view as by the environmental focus. For this the drainage, structural geology, physiographic unities and pedological basic environmental information were detailed through field and laboratory works (aerial photointerpretation). This information have enabled better undestanding of the landscape dynamic and evolution. Physiographic characterization for colluvial and alluvial units of the studied area permitted to establish the factors and processes, both endogenetic and geomorphic, that resulted in the landscape formation. The geoenvironmental zoning was defined by this purpose, which generate subdividing operations into structural and physiographic analysis, for as much as the potentiality and limitation determination of them as entities. The following thematic maps were obtained, therefore: erosion vulnerability, environmental protection indication and agricultural annual rotation. The results of the geoenvironmental zoning work in the Pirituba II Settlement allowed the definition of environmental planning detailed strategies in agreement with sustainable reality.
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Patagonian glacial reconstructions at 49°SGeiger, Alessa J. January 2015 (has links)
Patagonia has one of the most extensive and well preserved glacial geomorphic records of anywhere else in the world. This study provides empirical constraints of Patagonian Ice Sheet (PIS) configuration and dynamics during the last two glacial cycles and the Holocene at 49°S. In particular a chronology of palaeo-ice surface elevations, thickness changes and ice-thinning rates is developed. Cosmogenic surface exposure dating across eight mountain transects at Hielo Patagonico Sur (HPS) outlet glaciers' Viedma and Chico, and from eastern facing mountain valley glaciers, is utilised to reconstruct PIS ice-surface elevation changes through time. The earliest dated glacier ice thickness marker falls into MIS6 (Marine Isotope Stage). The last glacial cycle is characterised by continuous ice-surface elevation lowering from a maximum at MIS5a to the Antarctic Cold Reversal (ACR). Large scale PIS cover occurred between ca. 40-47 kyrs, in both the HPS outlet glaciers and the eastern mountain valleys. This regional ice-cover considerably pre-dates the global Last Glacial Maximum (gLGM). A gLGM vertical ice surface expression is absent from the study area. A minor re-advance and/or stillstand at ca. 18 kyrs is recorded by the valley glaciers, but is not evident at the HPS outlet glaciers. Glacier Viedma records a prominent ice elevation during the ACR with rapid thinning at the end of the climate perturbation. Ice-surface lowering from the ACR limit continues with acceleration toward the late-Holocene. The PIS palaeo-ice elevation and thinning record presented here is sensitive to internal PIS dynamics, local and global climate forcing acting on different timescales, with glacier response to climate perturbation strongly linked to glacier catchment size and distance from the main source of precipitation at 49°S.
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Classification and structural connectivity of urban vegetation : A comparative study using different datasetsLundberg, Malin January 2018 (has links)
Urban greenspace has an important role in supporting biodiversity and providing structural and functional connectivity between natural habitats. However, the mapping of vegetation in urban areas presents challenges, as urban vegetation is highly fragmented and heterogeneous. This study compared maps with respect to their strengths and weaknesses in providing ecologically relevant information in an urban area with the purpose to find how useful they are for local planning. The study took place in the urban part of Dún Laoghaire-Rathdown County, Ireland. The maps analysed were the Urban Atlas 2012 provided by Copernicus, the Prime 2 database provided by the Ordnance Survey Ireland, and two maps that were generated by this project from Sentinel 2 satellite imagery, one which showed vegetation based on calculated NDVI and one with four land cover classes calculated with a supervised classification. These maps were compared from three points of view: correspondence of vegetation classes, structural connectivity, and quality of vegetated areas. Analyses of structural connectivity were based on several landscape metrics, one of them was the degree of coherence (Cm) which reflects how connected the vegetation patches are in the landscape. Definition of quality was based on contextual indicators, such as the proximity to streams and areas with high conservation value, and vegetation present on a historical map from the 1830s. The results showed that the overlap of vegetation between the datasets varies between 27.0-89.1%. The different datasets definitions of vegetation affect how well they correspond in terms of where vegetation can be found. Resolution is also an important factor, as urban vegetation patches tend to be small and thus a coarse minimum mapping unit – as is the case for the Urban Atlas – masks important information on the configuration of vegetated areas in the urban area. The structural connectivity of vegetation differed little between Prime 2 (Cm = 7.95×10-2%) and the Urban Atlas (Cm = 5.87×10-2%). However, the distance between vegetated patches was on average shorter in Prime 2. This suggests that the Prime 2 dataset, because of its higher spatial resolution, contains more information on potential stepping stones for species to move around the landscape. The distribution of vegetated areas with higher contextual quality was mainly close to the boundaries of the urban area. Connectivity in a fragmented landscape like this urban study area plays a crucial role in maintaining populations of flora and fauna. It is therefore important to consider in the management of urban vegetation and in planning for development. This study offers a first insight in the structural connectivity of Dún Laoghaire-Rathdown County, which can be used to make more informed decisions that will sustain urban biodiversity.
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New insight into the drivers, magnitude and sources of fluvial CO2 efflux in temperate and arctic catchmentsLong, Hazel Elizabeth January 2016 (has links)
Freshwater systems are generally found to be sources of CO2 to the atmosphere and evasion of CO2 from fluvial systems is now recognised to be a significant component of the global carbon cycle. However detailed understanding of fluvial carbon dynamics and controls on the system is lacking and global coverage of published data is sparse, but thorough understanding across a broad range of locations is crucial if global carbon budgets are to be refined. This research addresses this lack of understanding by investigating the magnitude, controls and sources of CO2 efflux across five catchments with different catchment characteristics, global locations and climate-change sensitivities. In doing so new understanding is used to explore a novel method for large-scale upscaling of CO2 efflux, time series reconstruction of the source and magnitude of CO2 efflux and incorporation of an Arctic region into the global fluvial carbon budget. The magnitude of and controls on CO2 efflux are not well understood, although it has been suggested that increased flow velocity and turbulence can enhance CO2 efflux rates. This research uses direct and contemporaneous measurements of CO2 efflux (range: -3.53 to 107 μmol CO2 m−2 s−1), flow hydraulics (e.g. mean velocity range: 0.03 to 1.39 m s-1; shear Reynolds number range: 350 to 174000), and water chemistry (e.g. pCO2 range: 388 to 4660 ppm), at sites in three UK catchments to assess whether flow intensity (a term which is used to describe one or more measures of flow strength and turbulence) is a primary control on CO2 efflux. These field sites have been chosen as they have contrasting size and land use: Drumtee Water (DW), 5.7 km2 and rural, the River Kelvin (RK), 335 km2 and urban, and the River Etive (RE), remote and snow-melt influenced. At the more soil-dominated sites DW and RK, a strong positive logarithmic relationship exists between CO2 efflux and measures of flow intensity (e.g. shear Reynolds number, overall R2 = 0.69), but this relationship is strengthened by including pCO2 (overall R2 = 0.72). Flow intensity may have a key influence on CO2 influx, although data are limited. A method using visual classification of flow intensity shows promise for supporting large-scale upscaling of fluvial CO2 efflux, if classification of water surface state can be standardised. Movement of dissolved inorganic carbon (DIC) through the hydrological cycle is an important component of global carbon budgets, and how they may respond to changing climatic conditions. However uncertainty remains about the hydrological and biogeochemical controls on DIC transmission through a catchment. Using contemporaneous measurements of DIC concentration ([DIC]) and stable carbon isotope composition of the DIC pool (δ13CDIC), fluvial DIC at more soil dominated sites, DW and RK, is found to vary considerably in response to changes in catchment hydrology. At low flow groundwater dominates, and has similar composition in both systems ([DIC]: 1.5 mmol L-1 DW, 2.0 mmol L-1 RK; δ13CDIC: -9 ‰ DW and RK) indicating a common hydrogeological inheritance in DIC, that is comparable to that of other temperate and tropical locations. Differences in composition at high flow ([DIC]: 0.1 mmol L-1 DW, 1.0 mmol L-1 RK; δ13CDIC: -23 ‰ DW, -14 ‰ RK) reflect catchment land use, and a lower contribution of soil water to the DIC pool in the more urban catchment (RK). Measured diel cycles in DIC pool composition at DW indicate biological processes modify the pool, and time series reconstructions of pool composition and CO2 efflux at DW reveal seasonal- and flow-related patterns in this biological activity. Time series reconstructions also reveal that at DW terrestrial-aquatic-atmospheric carbon cycling is rapid during event flows, with large amounts of CO2, of soil-origin, effluxed to the atmosphere in relatively short periods of time. Conversely, at low flows, CO2 efflux is of smaller magnitude and primarily fuelled by groundwater, and terrestrial-aquatic-atmospheric carbon cycling is slower. The reconstructions allow for inter-year comparisons which are useful in assessing for behaviours in CO2 source and feedback that might be typical under climate change-induced changes in hydrology (e.g. wetter winters, drier summers, more frequent large flow events). Global ice melt and permafrost thaw are increasing due to climate change, effects of melting ice and thawing permafrost on the global carbon cycle, and carbon cycling dynamics of the melt/thaw waters are not well understood. Data from the River Etive has few similarities to that of DW and RK and indicates that snow- and ice- dominated systems may behave very differently to more soil-dominated systems in terms of magnitude and controls on efflux and sources and mixing of the DIC pool. This is confirmed by data collected from the melt/thaw waters of two cryospheric systems in Greenland: a Greenland Ice Sheet (GrIS) drainage river (Akuliarusiarsuup Kuua River, or AR) and the local permafrost-landscape surface-drainage systems (PLST). CO2 efflux appears independent of flow controls in both systems, and instead seems to be pCO2 limited (average pCO2: 115 ppm AR, 596 ppm PLST), with spatial variation in AR (efflux decreases downstream) and temporal variation in PLST (efflux decreases with melt season progression). The frequent occurrence of CO2 influx (measured in 64% and 14% of cases in AR and PLST respectively), which has rarely been reported from other rivers globally, reveals that Arctic fluvial systems can periodically act as net sinks of CO2 and this should be incorporated into global carbon budgets. The occurrence of CO2 influx, and dominance of air-water CO2 exchange in these low pCO2 systems, is reflected in the DIC pool composition which is 13C-enriched and approaches isotopic equilibrium with the atmosphere (~0 ‰), and indicates that soil and ground water contributes little to the DIC pool under frozen ground conditions. Radiocarbon analysis gives further insight into the source of carbon in these systems, revealing that the GrIS is releasing old DOC (~5200 to 6600 yrs BP) upon melting, which is considered to be highly biolabile and may prime bacterial activity and feedback to climate change, and meltwaters are returning old carbon (800 to 960 yrs BP) to the atmosphere via CO2 efflux. Thus it appears that climate change (via melting ice sheets) may be a driver of the age of atmospheric carbon composition. The effluxed CO2 being less old than the DOC indicates the source of CO2 efflux is a mixed pool of respired/UV-oxidised old DOC and modern atmospheric CO2 from drawdown. In contrast to GrIS meltwaters, and the permafrost of other global locations (e.g. the Siberian Yedoma deposits), the permafrost landscape of the Kangerlussuaq region of Greenland is cycling modern carbon and appears not to be degrading, as old carbon is not found in, or degassed from, the fluvial systems. In summary this research contributes to a greater understanding of fluvial carbon dynamics and the processes controlling the return of CO2 to the atmosphere via efflux, across an array of catchment types, sizes, land uses and global locations, and makes contributions of novel data to a number of areas of fluvial carbon cycling research where there are scarcities. Marked differences in the fluvial carbon cycling dynamics of cryospheric and snow-melt dominated systems compared to soil-dominated terrestrial systems are uncovered, novel upscaling attempts made using new findings of the research, and a number of exciting new research directions and opportunities that could enhance the findings of this work are identified. Overall, this research takes steps towards a greater understanding of fluvial carbon cycling dynamics on a global scale and improved projections of the likely response of fluvial systems to climate change, ultimately aiding the community to be more prepared for what our shifting climate will bring.
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Palaeoenvironmental reconstruction and geoarchaeology of the Cuatro Ciénegas Basin, NE Mexico, from the late Pleistocene to the presentFelstead, Nicholas James January 2012 (has links)
With over 200 pools, lakes and rivers supporting over 70 species of endemic flora and fauna, the Cuatro Cienegas Basin, Coahuila, NE Mexico is an extremely important and extensively studied area in terms of conservation. The palaeoenvironment, however, is relatively understudied with only two reconstructions published to date - Meyer [1973] and Minckley and Jackson [2008]. This project has analysed a 15 m carbonate sediment core for multi-proxy palaeoenvironmental information and combined this with stable isotope, modern hydrological and geoarchaeological information in the Cuatro Cienegas Basin.
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