Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 22 for “"dry valleys"”.
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Lacustrine biogeochemistry of the McMurdo Dry Valleys, Antarctica.
Lacustrine biogeochemistry of the McMurdo Dry Valleys, Antarctica.
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Microbial Mat Abundance and Activity in the McMurdo Dry Valleys, Antarctica
… to remote environments, such as in the McMurdo Dry Valleys (MDV) of Antarctica, where cyanobacterial communities are the main drivers of primary production. These microbial communities form multi-layered sheets (i.e., microbial mats) on top of desert pavement. The cryptic nature of these …
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Resolving Drivers of Microbial Community Structure in The Dry Valleys of Antarctica
… conditions that typify the continent. The Dry Valleys comprise the largest of these regions and have one of the simplest food webs on the planet, making them a tractable system to comprehensively define relationships that influence microbial distributions at the landscape scale. The New …
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The impacts of thermokarst activity on a stream in the McMurdo Dry Valleys
The McMurdo Dry Valleys (MDV) of Antarctica are a unique ice-free landscape that is host to vibrant ecosystems despite the harsh environment (<10 cm water equivalent/yr, -20°C mean air temperature). Aquatic ecosystems in the MDV are dependent on the ephemeral glacial runoff streams which feed the …
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Controls over the distribution of soil micro-invertebrates in the McMurdo Dry Valleys, Antarctica
The McMurdo Dry Valleys of Antarctica are a cold desert ecosystem where soil micro-invertebrate communities are shaped by extreme abiotic conditions, particularly low soil moisture, organic carbon availability, and high salinity. In this thesis I combine long-term ecological data with spatial …
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Resolving functional resilience of microbial communities to climate-induced change in the McMurdo Dry Valleys of Antarctica
The McMurdo Dry Valleys of Antarctica are an abiotically driven ecosystem characterized by having a very simple trophic structure dominated by microbial communities, whose diversity is shaped by extreme abiotic gradients, particularly extreme aridity and oligotrophy. Regional isolation and …
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Multi-scale Studies of Microbial Mats and Biocrusts: Integrating Remote Sensing with Field Investigations in Antarctica's McMurdo Dry Valleys
… and stability to soil surfaces. In the McMurdo Dry Valleys of Antarctica, microbial mats are the main source of fixed carbon in lentic and lotic environments, but their contribution to soil carbon and nitrogen cycling has not been systematically examined. In my dissertation, I investigated the …
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Influence of landscape-variation in geochemistry on taxonomic and functional composition of microbial mat communities in the McMurdo Dry Valleys, Antarctica
… and underlying soil communities in the McMurdo Dry Valleys of Antarctica across a gradient of phosphorus availability on glacial tills of distinct age and mineral composition in Taylor Valley, Antarctica. Microbial mat and soil DNA were extracted and sequenced on an Illumina NextSeq500 in a 150 …
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Cenozoic tectonic and geomorphic evolution of the Red River Region, Yunnan Province, China
… erosion history. This method is applied in the Dry Valleys region of Antarctica.
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Surface exposure geochronology using cosmogenic nuclides : applications in Antarctic glacial geology
… Antarctic glacial deposits in the McMurdo Sound-Dry Valleys region. The goals of this project were to provide age constraints for Antarctic glacial events, to investigate production mechanisms of 3He, lOBe, and 26 A1 in terrestrial rocks, to constrain the importance of loss of 3He from quartz due …
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Screening for novel cold-adapted nitrile hydratases in Antarctic metagenornic libraries
… constructed from soil taken from the McMurdo Dry Valleys in Antarctica were used for both functional and sequence based screens of NHases. Functional screens that were trialled were based on pH change and oligotrophic selective growth.
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Human impact on the McMurdo Dry Valley soils of Antarctica: Extending the limits of DNA detection
… an evidence-based risk assessment of the McMurdo Dry Valley ecosystem (DryVER project), this research quantified human impact, in the form of DNA released from humans and human-associated microbiota, across spatial and temporal scales. This project was part of the MBIE grant entitled …
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Environmental controls on the distribution of bacterial membrane lipids
… and in two ice-covered lakes of the McMurdo Dry Valleys, Antarctica. The results will enhance our ability to interpret the molecular fossil record, particularly those biomarkers that might preserve evidence of ancient marine and glacial environments. I will provide evidence that supports the …
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Investigations of rapid groundwater flow and karst in the Chalk
… and there is little surface karst, other than dry valleys, in Zone 3 where the Chalk outcrops. Tracer tests from three stream sinks in Zone 1 demonstrated connections to springs and rapid groundwater flow (1-6 km.d-1) indicating connected networks of conduits and large fissures over distances …
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Computer modeling and experimental work on the astrobiological implications of the martian subsurface ionising radiation environment
… novel cold-tolerant bacterial strains from the Dry Valleys environment of Antarctica, an analogue site to the martian surface, and determine their phylogenetic diversity and survival under high-dose gamma-ray exposure frozen at -79!C, a temperature characteristic of the martian mid-latitude …
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Constraining the pathways and fluxes of subglacial meltwater beneath the palaeo-Antarctic Ice Sheet
… channels known as the Labyrinth in the McMurdo Dry Valleys whose genesis has been attributed to catastrophic outburst floods, sourced from subglacial lakes during the Miocene. A similar process origin is proposed for the channels observed on the Antarctic continental shelf, formed through the …
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Repair eXtreme - DNA repair proteins from Antarctic extremophiles
The McMurdo Dry valleys (DV) in Antarctica are one of the harshest environments on Earth, with high levels of UV radiation, freeze-thaw cycles, low moisture, and nutrient content. Bacteria in this extreme environment have adapted to slow growth and low-nutrient conditions. It is proposed that …
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The late glacial and post glacial history of the Vale of Pickering and northern Yorkshire Wolds
… suggesting a probable glacial outwash source.The dry valleys were studied and new light shed on the processes which may have contributed to their formation. In addition evidence of periglacial evidence from the whole region was collected, described and assessed. Finally it was found that the …
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Environmental Controls Over the Distribution and Function of Antarctic Soil Microbial Communities
… in the polar desert of Antarctica's McMurdo Dry Valleys, a model ecosystem which hosts microbially-dominated soil foodwebs and displays heterogeneously distributed soil properties across the landscape. Results for Chapter 2 indicate differential effects of resource availability and …
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The resilience of Polar Collembola to climate change
… ice-free area in continental Antarctica, McMurdo Dry Valleys. I tested whether the genetic variation found between coastal and inland individuals of G. hodgsoni corresponded with differences in physiological tolerances of hot and cold temperatures was tested. Individuals from the population …
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