PHYSICAL GEOGRAPHY

Please contact named supervisors for an informal discussion of these research opportunities in physical geography.

Impacts of Structural Features on Urban Flood Inundation Under Climate Change Scenarios
Supervisors: Dr Dapeng Yu and Professor Rob Wilby
Urban fluvial flood inundation modelling is a challenging task primarily due to the topographic complexity arising from the presence of structural features such as buildings, road embankments and levees which may exert significant impacts on flood inundation. Modelling tools have been lacking in the area of urban flood modelling to account for the impacts of such features. This is a significant research area because the potential flood damage in urban areas is proportionately greater than in rural areas and urban flooding receives a high political profile. In this context, the functional relationship between flood magnitude and flood inundation extent in the presence of structural features needs to be established. Of particular concern here are the prospective changes in flood magnitude associated with anticipated climate change in the UK. This project seeks to address the sensitivity of inundation parameters (conveyance, stage and extent) to flow conditions under climate change scenarios. Both natural topographies and experimental topographies will be formulated. The 2000 flood event occurred on the River Ouse across the city centre of York will be used. This project will consist of field works and extensive use of numerical models.

Geomorphology and Sedimentology
of Topographically-Constricted Dunefields
Supervisors: Dr Joanna Bullard and Professor Helen Rendell
Whilst much is known about the development and dynamics of major dunefields and sand seas, comparatively little research has focused on small dunefields (<250 km2). The Atacama desert (Peru/Chile) is not well-known for its aeolian deposits yet there are numerous small, dynamic dunefields scattered throughout the region. These dunefields are topographically-constrained by the mountains of the coastal cordillera or the Andes and develop in small basins or valleys. Sediment is derived from the coast or from river systems. This project will focus on the evolution of the dunefields in relation to the tectonic history of the area and their palaeo- and contemporary geomorphology, sedimentology and bedform dynamics.

Diatom Taphonomy and Silica Cycling in UK Lakes

Supervisors: Dr David Ryves and Professor John Anderson
To investigate and quantify processes of diatom production, sedimentation and preservation in one or more lakes in the UK, and relate these to (1) limnological form and function (including both physical and biotic interactions, e.g. role of invertebrate communities and grazing); (2) silica dynamics (inputs, outputs, storage and solid/dissolved phase transformations), and apply results to evaluate and improve interpretation of biogenic silica records. Possibilities exist for limnological monitoring of one or more lakes, sediment trapping, diatom dissolution/preservation experiments (including effects of invertebrate digestion, excretion and bioturbation) and developing ways to improve both qualitative and quantitative interpretations of sedimentary diatom records.

Environmental Change in the Arctic
Supervisors: Professor John Anderson and Dr David Ryves
Arctic ecosystems are finely balanced and, as a result, very sensitive to anthropogenic disturbance. Global climate models indicate that future warming will be particularly pronounced at higher latitudes. It is difficult to fully evaluate possible effects of global change in the Arctic because we do not have long-term monitoring data and many of the process interactions at ecosystem level are not fully understood. John Anderson has been working in Greenland on global environmental change questions (e.g. Holocene climatic variability, lake-catchment interactions and atmospheric pollution of remote lakes) for a number years and this research has highlighted a number of directions for future research. Possible research topics include, for example; high-resolution studies of past climatic variability using sediment records from arctic lakes, catchment scale modelling of hydrological and material fluxes between land and aquatic systems, remote sensing of lake ice dynamics and carbon cycling in arctic lakes.

Climatological and Geomorphological Influences on Dust Event Detection

Supervisors: Dr Joanna Bullard and Dr David Graham

Atmospheric dust plays an important role in the global climate system. Research has been undertaken at global, continental and local scales to determine spatial and temporal patterns of dust erosion using a variety of techniques, notably meteorological and satellite data, but it is recognized that some dust events go undetected for a variety of reasons. This project will draw upon a variety of datasets to determine the pros and cons of using different data sources for identifying dust events with particular climatological characteristics and source geomorphologies. For example, does the weather system driving the dust event affect its detectability? How does the spatial distribution of dust plumes affect their detectability? Do dust source characteristics (e.g. geochemistry) affect the detection of plumes in transit?

The Role of Aquatic Fauna in River Sediment Dynamics

Supervisros: Dr Stephen Rice and Dr Paul Wood

Ecogeomorphology is the examination of the dynamic linkages and interactions between life (plants, animals and ecosystem processes) and landscapes (landforms, sediment dynamics and geomorphological processes). We are interested in extending our research in this arena, specifically work on how the sediment dynamics of rivers and river morphology are affected by river fauna. Answering some of the big questions (“How will fluvial processes and thence river morphology be affected as species shift under climate change?”) depends on a better mechanistic understanding of the ways in which biotic processes affect river sediment dynamics and the feedbacks to ecological health. Thus we need to know more about the ways in which river fauna affect sediment erosion, mobilisation and deposition and how such modifications of the physical environment by an organism increase its ecological advantage (ecosystem engineering). A key issue in this is developing robust ways of scaling up small-scale case studies and experimental work to larger scales. Thus, we can show that crayfish activity has an impact of gravel-bed entrainment stresses, but do crayfish populations therefore affect whole-catchment bed load yields? We are interested in supporting PhD research in this general field and welcome proposals from interested students from either a geography or ecology background.

The Impacts of Large Herbivores on Forest Regeneration

Supervisors: Dr Jonathan Millett and Dr Stephen Rice

Large herbivores such as Red Deer (Cervus elaphus) have important impacts on the regeneration of native woodland in the UK. At relatively high densities they prevent the establishment of seedlings. At lower densities they still have important impacts on the plant community by altering plant-plant interactions, plant physiology and plant responses to stress. This study will investigate the impacts of Red Deer on tree regeneration in Scotland using sites where deer management is reducing deer densities sufficiently to encourage the establishment of native woodland. Two such sites are Dundreggan and Creag Meagaidh. The response of Betula spp. will be assessed in response to the interaction of herbivory with plant-plant interactions, tree physiology and/or environmental stress. Studies of tree responses in-situ may be combined with ex-situ studies carried out at Loughborough University.

The Physiological Ecology of Carnivorous Plants
Supervisors: Dr Jonathan Millett

Carnivorous plants attract, trap and digest insects, utilising the products of digestion for growth and reproduction. These marvels of the natural world are fascinating in their own right, but they are also ideal models for testing general ecological theories. The ‘costs’ of being carnivorous restrict carnivorous plants to moist, open, nutrient poor environments. Thus these plants are particularly sensitive to changes in the abiotic (e.g. eutrophication) or biotic (e.g. competition) environment, making them sensitive indicators of global environmental change. A number of models have been postulated, predicting the response of carnivorous plants to changes in nutrient and/or prey availability. This project will test the predictions of these models using species native to the UK and/or other parts of the world. These predictions will be tested in-situ, utilising existing differences in nutrient availability, or ex-situ, for example by utilising an existing study at Whim Bog near Edinburgh where different levels of N deposition are being simulated in an existing bog, or in glasshouse studies. The use of stable isotopes will enable the interaction between root and insect derived nutrients to be investigated.

Image-Analysis Approaches to Sediment Texture Characterisation
Supervisors: Dr David Graham and Dr Stephen Rice

Recent years have seen substantial advances in automated measurement technology for the in situ characterisation of coarse-grained sediments (e.g. gravel bars). The approaches taken have been based on either ground-based photographic identification of individual particles, or statistical analyses of airborne imagery. Both of these technologies have limitations that a hybrid approach could address. This project will identify optimal image scales for a variety of published measurement approaches and use this information to define new hybrid and scaleable procedures. It will utilise the department's 15m photographic mast and remote-controlled camera. The research will consist of field and lab work combined with extensive computer-based image analysis.

Assessment of the Significance of Polythermal Glaciers in Scotland
Supervisors: Dr David Graham and Dr Richard Hodgkins

It has generally been assumed that British Younger Dryas glaciers were predominantly warm-based. There is now evidence that some of these glaciers may have been polythermal in character, originating either from cold-based plateau icefields or having a cold-based margin. This is significant, because polythermal ice requires very specific climatic conditions. This project will attempt to quantify the proportion of Scottish Younger Dryas for which there is evidence of a polythermal character and identify the factors that control their distribution. The research will be based on a combination of air photo interpretation and fieldwork.

The Ecological and Geomorphological Significance of Stream Confluences
Supervisors: Dr Stephen Rice and Dr Paul Wood
The hydraulic, morphological and sedimentological characteristics of confluences have been widely studied and their impacts on longitudinal river morphology and sedimentology are generally acknowledged, but the role of confluences in organising stream fauna is poorly understood. Confluences are sites along a main channel where, because of the introduction of water and/or sediment, the water volume, bed-sediment character and water quality of the mainstream can change abruptly. Resulting changes in physical habitat make the confluence region itself a particularly diverse and complex location. This project will examine the nature of macroinvertebrate habitat within river confluences and explore the characteristics of confluence communities in comparison with other sites. The project will involve fieldwork that requires both ecological and geomorphological training and skills. This project sits at the exciting interface between fluvial geomorphology and lotic ecology; an area that is increasingly recognised to be critical for the sustainable management of river systems.