PhD Research Opportunities

The UCL Department of Geography invites applications from suitably qualified students for PhD opportunities from April 2012 onwards. Please contact the appropriate member of staff directly to propose a research topic (under their key research themes) or to request further details of a specific project. Further details relating to funding opportunities and application information can be found here. Not all projects are eligible for funding, so please check with staff or the Graduate Tutor before applying (NERC project eligibility is noted).

Staff (and links to their homepage)	Key Research Themes	Links to Specific Projects
Pushpa Arabindoo	- New middle class and the politics of urban development in the global South - Environmentalism and elitism in cities of the global South - Religion and diaspora - Pious circuits of capital - Preferred area of focus: South Asia
Jan Axmacher	- Biodiversity conservation and conservation biology, especially in relation to terrestrial arthropods and vascular plants - Geographically, projects based in Europe or other temperate regions (China), as well as in the tropics
Helen Bennion	- Aquatic ecology and palaeoecology - Diatom taxonomy and applications - Impacts of eutrophication on standing fresh waters over a range of time scales - The use of the lake sediment record to assess environmental change, reference conditions and restoration targets - Application of science to lake management and conservation, particularly the EU Water Framework Directive	Understanding early diatom changes in shallow lake sediment cores: Diatoms assemblages as early warning signs?
Caroline Bressey
Chris Brierley		Tropical cyclones in the climate system
Helene Burningham	- Meso-scale (historical) coastal morphodynamics - Seabed morphodynamics - Conservation and ecology of coastal sedimentary environments - Estuary-coast interaction and inlet dynamics - Coastal GIS - Estuarine morphology and sedimentology - mixed energy systems
Gail Davies	- The reconceptualisation of nature-society relationships and alternative ways of thinking about and living with nature - The relevance of materiality and spatiality in social relations, including through consideration of food, plants, animals and biotechnology - The relationship between and innovative forms of engagement with lay and expert knowledges - The geographies of science and technology
Richard Dennis	- Historical geographies of 'modern' cities, c. 1800-1950, esp. related to (1) housing; (2) transport - Urban Canada - The production of space in 19th- and early 20th-century urban fiction
Paul Densham
Mat Disney
Jason Dittmer	- Geographies of media, especially comic books - Critical geopolitics, especially popular geopolitics - Diplomacy and the everyday state - Religion and geopolitics
Claire Dwyer	- Geographies of race, racism and ethnicity, - Transnationalism and diaspora identities, - Geographies of religion
Jurgen Essletzbichler
Roger Flower		Environmental change in an upland acid stream:  monitoring and modelling to help assess the impacts of simulated climate change and acidity scenarios on water quality and stream biology
Jon French	- Numerical modelling of coast, estuary and lake systems
Matthew Gandy
Andrew Harris	- Urban infrastructure especially transport - Vertical geographies - Urban regeneration, gentrification, creative cities - Art, sound, space and the city - The travel/transfer of urban policy and planning
Russell Hitchings	- Material culture and ways of making consumption more sustainable - Everyday life and cultural practices of keeping human bodies warm and cool - Contextual studies of social practice and social norms - Ways of living with climate in terms of weather and the seasons - Interviewing, ethnography and other qualitative methods
Jonathan Holmes		Reconstruction of Quaternary climate and hydrology from non-marine ostracods – developing a new approach combining palaeoecology and stable isotope geochemistry Historical and recent salinity fluctuations in the Thurne Broads: Implications for nature conservation
Alan Ingram	Political geography and geopolitics, with particular reference to: - Governmentality, biopolitics and security - Global health issues - Relationships between geopolitics and art - Nationalism
Peter Jones
Viv Jones
James Kneale	- Geographies of alcohol, drinking places, health, alcohol policy and abstinence (historical and contemporary); life insurance, governmentality and the 'financial subject' - Representations of space in fiction, particularly non-realist fiction: science fiction, the fantastic, etc
Alan Latham
Charlotte Lemanski	- South African post-apartheid urban transformation - Contemporary Indian urban processes of participation and governance - Fear and (in)security in cities - Poverty and urban governance - Urban housing and land (for low- and high-income households) - Migration from Southern Africa to the UK - Urban segregation and territorialisation	Property formalisation in urban India
Philip Lewis
Simon Lewis
Paul Longley	- Geographic information systems and science - Geodemographics and socio-economic applications of GIS - Geo-genealogy: the quantitative analysis of family names - Information integration within GIS - Public service delivery (specifically health, education and policing) - Internet GIS applications and e-social science - Housing and retail market analysis - Fractal analysis of cities - Social survey research practice	http://paul-longley.com/funding/
Anson Mackay		Climate change and pollution impacts on productivity and biodiversity in the Selenga River Delta: a Siberian, Ramsar wetland of international importance
Mark Maslin
Pablo Mateos
JoAnn McGregor
Ben Page	- Migration and Development - Environment and Development - Housing and architecture in West Africa - Transnational Weddings - Political Ecology of water supply - West Africa - African diaspora
Samuel Randalls
Jennifer Robinson	- Urban politics and development in South African cities - The role of UCL in the urban development politics of London - Urban comparative studies - Mobilising community voices at the metropolitan-scale - Rethinking neoliberalism and urban governance - Urban policy mobilities
Neil Rose	- Impacts of atmospheric pollutants such as heavy metals and and fossil-fuel derived particulates on the environment on a UK, European and global scale - The spatial and temporal distributions of trace metals and fly-ash particles - The use of the lake sediment fly-ash particle record as a chronological tool - Temporal aspects, and drivers, of sediment accumulation rate changes in lakes - The remobilisation of contaminants in catchments and their transfer to freshwater systems	The impact of eroded lake catchments on the contaminant content of biota
Carl Sayer
Richard Taylor
Julian Thompson	- Wetland hydrology, management and conservation - Hydrological modelling with particular focus on wetlands	Development of tool and approaches for the assessment of hydrological model structure and parameterisation uncertainty for scenario analysis
Chronis Tzedakis		Changes in vegetation and the hydrological cycle in the Mediterranean during Marine Isotope Stage 11
Ann Varley	- Urban land and housing especially in Latin America - Home - Law, property and urban governance - Urban informality - Gender, families and households - Ageing - Social aspects of disasters and vulnerability

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PhD title:

Changes in vegetation and the hydrological cycle in the Mediterranean during Marine Isotope Stage 11

First supervisor:

Chronis Tzedakis

Second(other) supervisor(s):

Mark Maslin

Abstract/outline:

Of the various geologically recent interglacials, the interval centred around 400 thousand years ago, known as Marine Isotope Stage 11, had an orbital configuration very similar to that of the present interglacial, characterized by low amplitude variations in insolation. However, the contrast between the moderate insolation signal and the strong climatic response does not fit well with Milankovitch orbital theory and for that reason is difficult to model successfully. Moreover, while in some records MIS 11 stands out as a prominent interglacial, in others it does not appear very different to the Holocene. Regional studies are therefore required to specify the development of the terrestrial and oceanographic conditions of this period. One way to address this is through joint pollen and palaeoceanographic proxy analyses in the same marine archive recovered adjacent to the continent. This allows an in situ assessment of phase and amplitude relationships between climate changes and the vegetation response, bypassing correlation uncertainties. To date, a substantial body of evidence from the Iberian margin has led to improved insights into the timing and duration of interglacial conditions in SW Europe and the response of vegetation to climate variability. These data have also revealed a strong coherence between changes in tree populations and atmospheric CH4 concentrations on orbital and millennial timescales, reflecting variations in the continental hydrological balance. Previous work from the Portuguese margin has revealed the presence of two peaks in sea surface temperatures and tree population expansion during the interval of full interglacial conditions, with the second peak as the more prominent. However, it remains unclear whether the same pattern is also observed further east in the Mediterranean, where marine-terrestrial records are currently not available. The proposed project will examine changes in vegetation and the hydrological cycle during MIS 11, by generating pollen records from marine sequences in the Western and Central-Eastern Mediterranean Sea. These will be combined with ongoing analyses of palaeoceanographic proxies from the same sequences, which will provide better constraints on links between key parameters in the climate system.

References/Suggested Reading

Desprat et al. (2005) Is vegetation responsible for glacial inception during periods of muted insolation changes? Quat. Sci. Rev. 24, 1361-1374 Loutre M. F. & Berger A. (2003) Marine Isotope Stage 11 as an analogue for the present interglacial, Global Planet. Change, 36, 209-217. Tzedakis, P.C. et al. (2009) Atmospheric methane, southern European vegetation and low-mid latitude links on orbital and millennial timescales. Earth Planet. Sci. Lett. 277, 307-317.

Funding/Costs

Significant extra costs that may be incurred include: Chemical preparation of samples: £2,000; Travel and subsistence to IODP Core Repository Bremen: £600; XRF scanning in Bremen: £400: Total: £3,145

PhD title:

Property formalisation in urban India

First supervisor:

Charlotte Lemanski

Second(other) supervisor(s):

Ann Varley

Abstract/outline:

Debates on property formalisation for the urban poor are well established in Latin America. Property formalisation essentially awards poor people legal title to property they already informally own thus integrating them in the capitalist market by building an asset and securing collateral. This research extends property formalisation debates from Latin America (and to a lesser extent, Africa), to a new empirical setting: urban India. Conflicts over land ownership are not new in India, exemplified by frequent slum demolition. The unauthorised colonies that house half of Delhi population, lacking legal tenure or access to services, are currently fighting for formalisation (regularisation). This research considers Delhi 2008 regularisation drive and ongoing court cases. The research will explore how courts function to undermine and/or strengthen human rights in the context of land and housing in Delhi unauthorised colonies. Primary fieldwork in Delhi will involve interviews with unauthorised colony residents, government officials, politicians and legal actors.

PhD title:

The impact of eroded lake catchments on the contaminant content of biota

First supervisor:

Neil Rose

Second(other) supervisor(s):

Anson Mackay; Handong Yang

Abstract/outline:

It is well known that lake and river catchments in upland areas of the UK and northern Europe have become increasingly eroded over recent decades. Catchment soils contain a store of contaminants, such as trace metals and persistent organic pollutants, a legacy of deposition from a 200-year industrial history. Catchments therefore contain a massive reservoir of contaminants with the potential to be released to surface waters. Recent research has shown that catchment soil erosion has led to enhanced metal inputs to lake basins such that the expected decline in inputs resulting from the dramatic reductions in the emissions of trace metals to the atmosphere since the 1970s is being negated. Furthermore, the effects of predicted climate change will enhance erosive processes and elevate pollutant transfer from catchment to surface waters. The scale of the catchment storage of these deposited pollutants is such that this remobilisation could keep contaminant sediment concentrations and fluxes elevated for many decades to come. This would negate the effects of emission reductions policies, contradict the aims of the EU Water Framework Directive (WFD) and may elevate exposure of aquatic biota. This is of particular importance as the Water Framework Directive (2008/105/EC) reaffirms the aim of the WFD to ensure that existing levels of contamination in biota and sediments will not significantly increase. However, although the input of metals is known to have increased, there is no information on whether this is being translated into elevated contamination of aquatic flora and fauna. This study would look at the effects of this enhanced input on the ecosystems of lakes with eroded catchments to assess the scale of impact and the implications for transfer along the food chain. To do this the study would include a number of lakes with varying levels of erosion and include sediment and biotic sampling across a range of trophic levels and detailed tarce metal analysis.

Funding

Please note travel and analytical costs are likely to be significant.

References/Suggested Reading:

Rose N.L., Monteith D.T., Kettle H., Thompson R., Yang H., Muir D.C.G. (2004) A consideration of potential confounding factors limiting chemical and biological recovery at Lochnagar, a remote mountain loch in Scotland. Journal of Limology 63: 63-76. Rothwell J.J., Robinson S.G., Evans M.G., Yang J., Allott T.E.H. (2005) Heavy metal release by peat erosion in the Peak District, southern Pennines, UK. Hydrological Processes 19: 2973-2989. Rothwell J.J., Evans M.G., Allott T.E.H. (2007) Lead contamination of fluvial sediments in an eroding blanket peat catchment. Applied Geochemistry 22: 446-459. Yang H., Rose N.L., Battarbee R.W., Boyle J.F. (2002) Mercury and lead budgets for Lochnagar, a Scottish mountain lake and its catchment. Environmental Science & Technology 36: 1383-1388.

PhD title:

Understanding early diatom changes in shallow lake sediment cores: Diatoms assemblages as early warning signs?

First supervisor:

Helen Bennion

Second(other) supervisor(s):

Carl Sayer; Iwan Jones

Abstract/outline:

Diatoms are extremely sensitive to environmental changes in lakes. They have been used for decades by palaeoecologists to reconstruct past lake conditions and most recently there has been a heavy focus on the determination of former nutrient levels using transfer functions. Nonetheless, despite thousands of diatom-based palaeolimnological papers, due to a lack of parallel work on diatom ecology (other than studies of chemical preferences), it is probably true that the full palaeolimnological potential of diatoms is yet to be exploited. This may be particularly true of shallow lakes where early diatom changes in cores are often dominated by species replacements amongst periphytic taxa. Indeed, where this is the case, interpretation of diatom sequences has usually proved problematic, although such changes are probably the first warning signs of ecological degradation and it is crucial that we understand what they may indicate. Controls over periphytic diatom communities are likely to be complex, involving interactions between several variables. These factors may include water chemistry, habitat structure, grazer communities (and hence the food web) and hydrology (turbulence etc.). To improve understanding of initial changes to diatom sequences of shallow lakes, in this study we will consider the relative importance of these different controls on epiphytic diatom communities and biofilm structure. A range of approaches will be utilised to address this key aim including contemporary field studies along gradients (grazing invertebrates + nutrients), field experiments (e.g. changing diatom communities in relation to hydrological exposure) and multi-factor tank experiments. Finally, hypotheses derived from these studies will be applied to diatom core profiles from sites with known environmental changes.

PhD title:

Reconstruction of Quaternary climate and hydrology from non-marine ostracods developing a new approach combining palaeoecology and stable isotope geochemistry

First supervisor:

Jonathan Holmes

Second(other) supervisor(s):

Tim Atkinson (UCL Earth Sciences); Dr Dave Horne (Queen Mary, University of London)

Abstract/outline:

Ostracods are microscopic, aquatic crustaceans that are common in most natural waters, including lakes. Their calcite shells are often preserved in lake sediments. Their distribution of non-marine ostracod species is determined by water temperature, ionic composition and salinity, hydrological setting and habitat type and fossil ostracod assemblages can be used to reconstruct past environment and ostracod shell provides an important source of calcite for stable isotope analysis. The oxygen-isotope composition of lacustrine carbonate is controlled by the isotopic composition of lake water and by water temperature. If the oxygen-isotope composition of lake water can be reconstructed with confidence, it is possible to derive valuable palaeoenvironmental information about water balance and catchment-scale hydrology as well as the isotopic composition of precipitation, which itself varies with atmospheric circulation. Attempts to reconstruct the past isotopic composition of lakewater are often frustrated, however, by the lack of an independent water temperature reconstruction. In this project, the student will develop a method for the reconstruction of the oxygen-isotope composition of palaeo-waters using a combination of isotope analysis of ostracod shells and other suitable materials with independent temperature estimates using the newly-developed Mutual Ostracod Temperature Range (MOTR) technique. To date, the MOTR method of palaeotemperature reconstruction has been combined with oxygen-isotope analyses of ostracod shells in just one pilot study, which was undertaken on material from Boxgrove, an important Middle Pleistocene archaeological site on the south coast of England. The results from Boxgrove are encouraging and agree well with other proxy data for the site. This pilot study therefore forms an excellent starting point for this project, from which the technique can be developed and refined. The student will first apply MOTR reconstructions and stable isotope analyses to a series of well-characterised modern non-marine sites, in order to evaluate the technique against instrumental data. Next, the approach will be applied to fossil sites from NW Europe, with emphasis on those of Lateglacial and Middle Pleistocene age. Statistical analysis of the faunal and isotopic data will be used to assess uncertainties in the water isotope reconstructions. Where site factors are favourable, we shall use the method to reconstruct the isotope composition of palaeo-precipitation and assess its palaeoclimatic significance. Ostracod MOTR estimates will be compared with published or unpublished palaeotemperature reconstructions from other biological proxies for sites where these exist. Isotope determinations will be undertaken on different species of ostracods in order to assess seasonality and offsets from isotopic equilibrium. Other biological materials, including mollusc shell, may also be used along with carbon and strontium isotope and trace-element signatures from the ostracods, where appropriate. Overall, this project will provide an exciting opportunity to develop and apply a new palaeoclimate proxy. The student will join the large, multidisciplinary Environmental Change Research Centre within the department of Geography at UCL and will receive training in ostracod taxonomy, ecology, and stable isotope analysis. He/she will be able to attend relevant advanced research training courses in palaeoenvironmental analysis held annually at UCL.

References/suggested reading:

Holmes et al., 2010, Quat. Sci. Rev. doi:10.1016/j.quascirev.2009.02.024. Horne, 2007, Quat. Sci. Rev., 26, 1398-1415

PhD title:

Historical and recent salinity fluctuations in the Thurne Broads: Implications for nature conservation

First supervisor:

Jonathan Holmes

Second(other) supervisor(s):

Carl Sayer; Dan Hoare (Broads Authority); Ian Holman (Cranfield)

Abstract/outline:

The Thurne Broads (including Hickling Broad, Heigham Sound, Horsey Mere and Martham South and North Broads) are a collection of shallow (<2 m), largely brackish lakes created by medieval peat cutting in the 12-14th centuries. They are key sites for nature conservation being part of the Upper Thurne Site of Special Scientific Interest (SSSI) and having status as a National Nature Reserve (NNR), EU Special Area of Conservation (SAC) and Ramsar site based primarily on substantial stands of charophyte macro-algae and important populations of wetland birds. Currently these Broads have high salinities (ranging from ~1500 to 2900 mg L-1) and much evidence suggests that salinity has increased within them since at least the 1950s linked to changes in hydrology and land-use in the catchment. Indeed recent palaeolimnological research at Hickling Broad has shown an upturn in salinity possibly since dramatic sea floods in 1938. Nevertheless, the timing, magnitude and rates of salinity increases in different parts of the Thurne hydrological system remain relatively poorly understood, while the ecological implications (particularly in terms of charophyte responses) of these changes are in dispute.In the last decade, there has been a steady decline in the ecological integrity of the Thurne Broads ecosystem. In particular the Hickling Broad-Heigham Sound region has seen a recent (post-1999) and dramatic loss of its important charophyte populations. Further, in the Martham Broads recent plant surveys (2008-2009) have revealed substantial holes in formerly extensive charophyte beds, suggesting the onset of ecological decline. Local opinion holds that a substantial recent influx of saline water (in November 2007) may have induced the charophyte decline at Martham. Currently the Martham Broads possess enormous conservation value due to the substantial stands of rare and Red Data Book charophytes that they support and hence, similar to the Hickling-Heigham system, an understanding of the hydrological and salinity context to the decline is of critical importance to inform management. The aim of this project is to investigate long-term (past ~500 years) salinity changes and ecosystem responses using a combined palaeolimnological and hydrological modelling approach. The specific objectives are 1) to reconstruct the long-term salinity of the Thurne Broads system using the trace-element (especially Mg and Sr) content of the calcitic shells of ostracods, which are microcrustaceans, preserved within lake sediments 2) to calibrate the reconstructed palaeosalinity of the system using long documentary records of salinity 3) to examine spatial variations in temporal salinity patterns using multiple-core studies in each of the major Broads 4) to investigate the response of the aquatic ecosystems, especially the aquatic macrophytes (including charophytes),  using plant macrofossil analysis 5) to investigate the links between salinity, water level management and climate using a combination of historical literature, catchment water balance modelling and groundwater analytical flow equations. We have shown that ostracods are abundant and well preserved within the sediments of the Thurne Broads. Changes in the trace-element content of ostracod shells from the dated sediments from Hickling Broad show good agreement with historical changes in salinity from documentary records. This pilot study provides an invaluable proof-of-concept for the proposed studentship, which will build on the preliminary work by investigating spatial variations within the system, developing more robust palaeosalinity reconstructions, and examining the links between salinity changes and aquatic ecosystems responses using plant macrofossil analysis and hydrological modelling. The work will provide a detailed, long-term history of salinity and ecosystems change for the Thurne Broads system and template for the study of similar marginal-marine systems elsewhere. Added value will be provided by Cranfield University long established research in the Thurne on catchment, river and groundwater modelling. The project will suit students with interests in aquatic ecology/palaeoecology, aquatic conservation ecology, microfossil analysis and hydrological modelling. Appropriate training will be provided in one of more of the following as required: ostracod analysis, ostracod shell chemistry, plant macrofossil analysis, numerical analysis of palaeoecological data, palaeolimnology (UCL), and hydrological modelling (Cranfield).

References/suggested reading:

Holmes et al. (2010) Freshwater Biology 55, 2484-2498

PhD title:

Tropical cyclones in the climate system

First supervisor:

Chris Brierley

Second(other) supervisor(s):

Abstract/outline:

Tropical cyclones (also known as hurricanes and typhoons) can have disastrous human impacts. There is substantial interest in the response of tropical cyclones to climate change in both the media and the scientific community (Knutson et al., 2010). Recent evidence suggests they may also affect the dynamics of the climate system, in part through the strong vertical mixing they cause over the ocean. This vertical mixing can be estimated from observed storms, but its role in the climate system is still uncertain – initial estimates that cyclones transport 1.5x1015 of heat towards to poles (a substantial fraction of total ocean heat transport) have not been confirmed by subsequent work. However, it has been suggested that tropical cyclones play a role in explaining the tropical changes seen in past warm climates (Fedorov et al., 2010). The majority of the work in the field so far has involved incorporating idealized representations of tropical cyclone mixing into climate models. This has either been a constant mixing field derived from observations or a dependence on an atmospheric variable related to hurricane intensity. Neither technique really accounts for any changes in location and path that might be expected under climate change. Initially this project will involve an analysis of the small disturbances (called seeds) that can develop into cyclones under the atmospheric right conditions. Any change in number or location of the storm seed would influence how the distribution of tropical cyclones varies with climate change. This analysis will use both existing high-resolution model simulations and atmospheric reanalyses to determine how seeds are related to the climate conditions. The ultimate aim of this work is to incorporate a tropical cyclone downscaling technique into a global model that will interactively include the role of the storms in the climate system.

References/suggested reading:

Fedorov et al. 2010. Tropical cyclones and permanent El Niño in the early. Pliocene Epoch, Nature, 463, 1006. Knutson et al. 2010. Tropical cyclones and climate change. Nature Geoscience, 3, 157-163.

PhD title:

Environmental change in an upland acid stream: monitoring and modelling to help assess the impacts of simulated climate change and acidity scenarios on water quality and stream biology

First supervisor:

Roger Flower

Second(other) supervisor(s):

Julian Thompson

Abstract/outline:

For good reason, mountain headwater streams are often referred to as the water towers of the world: they are key systems for supplying freshwater for people and for biodiversity. Yet predicted global warming and hydrological changes together with long distance atmospheric pollutants such as anthropogenic nitrogen pose major threats to the sustainability and ecological integrity of upland waters. For one catchment system in southwest Scotland, hydrological modelling of stream discharge has already indicated how freshwater availability is likely to change in the next fifty years according to several climate change scenarios. In this research proposal we will seek to refine the hydrological model (using Mike-SHE and MIKE11 software) and to incorporate aspects of water quality and stream ecology. The work will build upon over twenty five years of ecohydrological monitoring in one upland catchment (Loch Dee) in Galloway where clear changes in runoff salinity, dissolved organic carbon and stream ecology have already been demonstrated as result of relief from acid deposition and climate variation. By introducing a period of high resolution water quality sampling and stream ecology, it is anticipated that stream chemistry and biology can be better interfaced with routinely collected daily hydrological data. Both short term (weather) and longer term (global warming effects and NAO changes) affect stream hydrology and water quality that impact stream ecology on several scales depending on discharge, water chemistry and season. The possibility of linking stream salinity, dissolved organic matter and dissolved nitrogen with discharge would extend model predictive capability. One intriguing aspect concerns the impact of exceptional hydrological events on stream ecology and water chemistry, especially in regard to community composition and the abundances of epilithic miroalgae in particular. The successful candidate will receive training in general field techniques for stream monitoring and will take a special interest in the micro-algae (diatoms). Training in hydrological modelling will also be given and some numerical analysis of the collected data will be needed.

References/suggested reading:

PhD title:

Understanding the role of recent environmental change in the decline of the Madagascan Pochard Aythya innotata

First supervisor:

Viv Jones

Second(other) supervisor(s):

Steve Brooks (Natural History Museum); Geoff Hilton (Wildfowl & Wetlands Trust Slimbridge)

Abstract/outline:

This project is a pioneering study combining palaeolimnological techniques with the conservation of  the globally endangered Madagascan Pochard. It will involve field work in Madagascar. Madagascar is a biodiversity hotspot. Endemism is extremely high, but rates of ecological degradation are extremely high too. The freshwater wetlands of Madagascar are particularly threatened. Extensive deforestation has caused high rates of soil erosion. The Madagascar Pochard Aythya innotata, is an endemic diving duck that was believed extinct until a small population was rediscovered in 2006 from a single lake in the highlands of northern Madagascar where a breeding programme has been established.  Managers need to understand the bird’s requirements and baseline conditions for lakes in the area. Objectives •    Assess impacts of recent environmental change on Pochard populations •    Determine ecological attributes of sites suitable for re-introduction of the Pochard. Methods •    Palaeolimnological techniques will be used to assess changes in lake ecosystems over the last 150 years using short sediment (0.5 to 1.0 m) cores from a spectrum of lakes •    Past changes in sedimentation rate, will be assessed from 210Pb dated cores. •    Changes in the invertebrate community structure will be assessed by analysing the abundance and diversity of  Chironomidae. •    Changes in terrestrial vegetation will be reconstructed by pollen analysis. •    Diatoms analysis will be used to indicate changes in trophic status and pH of the lakes.

References/suggested reading:

Bennion, H., Battarbee, R.W., Sayer, C.D., Simpson, G.L., and Davidson, T.A. (2011) Defining reference conditions and restoration targets for lake ecosystems using palaeolimnology: a synthesis. Journal of Paleolimnology 45(4), 533–544.

PhD title:

Development of tool and approaches for the assessment of hydrological model structure and parameterisation uncertainty for scenario analysis

First supervisor:

Julian Thompson

Second(other) supervisor(s):

Jon French

Abstract/outline:

Hydrological models provide important tools for assessing the impacts of a varying scenarios ranging from those associated with water management interventions to their widespread use for climate change assessments. The latter is routinely undertaken by forcing meteorological inputs (e.g. precipitation, temperature, evapotranspiration) to a previously calibrated hydrological model in line with projections from global climate model (GCM) simulations for different emissions scenarios. Such approaches are associated with a range of uncertainties. These include differences in both baseline and future climate simulated by different GCMs. The impact of such uncertainty can be assessed by employing a suite of different GCM projections (e.g. Kingston et al., 2011; Singh et al., 2010). Areas of uncertainty which have received relatively less attention are those associated with model structure and parameter uncertainty. Complex fully distributed hydrological models such as MIKE SHE, especially when used to simulate large river basins, are characterised by many parameters which are often used as calibration terms. The number of parameters available requires the use of autocalibration routines with the potential that it may be possible to obtain equally good model performance (the ability to represent observed hydrological conditions such as river flow) with different model parameter sets. Existing autocalibration routines within MIKE Zero (the user interface in which MIKE SHE models are developed), based on Monte Carlo sampling from a defined parameter space (e.g. Madsen, 2003; Thompson in press), impose large computational demands and extended calibration periods. In many cases one single “optimum” model is selected for subsequent scenario analysis. In this way, a single prediction of change associated with a given scenario may be derived which does not reflect the uncertainty associated with model parameter variability. Similarly, choices made at the outset of model development, such as those associated with the model structure including the spatial distribution of input data, model resolution, the discretisation of a catchment into sub-catchments and the choice of method used to represent a given hydrological process (e.g. potential evapotranspiration - Kingston et al., 2009), may all have impacts upon model operation and subsequent results when a model is used to investigate alternative scenarios. The impact of such choices is rarely considered. This PhD project aims to investigate these issues. Existing MIKE SHE models (which could include those developed for catchment ranging from small catchments in SW Scotland (Thompson, in press) to large international rivers basins such as the Mekong) will be employed whilst at least one new model of a large catchment will be developed using extant global data sets. The research will include (i) the development of approaches to employ the PEST (Model-Independent Parameter Estimation and Uncertainty Analysis) package for MIKE SHE models; (ii) a comparison in terms of both optimal model selection and the computational resources required for calibration of existing autocalibration routines available within MIKE Zero and those facilitated by the linkage to PEST; (iii) reconfiguration and subsequent recalibration of models to reflect different structures (e.g. spatial distribution of inputs, sub-catchments, process formulation); (iv) assessments of the uncertainty associated with model parameter and model structure uncertainty for scenario analysis with an emphasis on climate change but also with the potential to investigate other scenarios depending upon catchment setting (e.g. land cover change in catchments experiencing large-scale anthropogenically induced modifications such as deforestation in the case of the Mekong). The project will benefit from the long-term collaboration between UCL Geography and DHI as well as with Daniel Kingston (University of Otago, New Zealand).

References/suggested reading:

Kingston, D.G., Todd, M.C., Taylor, R.G., Thompson, J.R., Arnell, N.W. 2009. Uncertainty in the estimation of potential evapotranspiration under climate change. Geophysical Research Letters 36, L20403. Kingston, D.G., Thompson, J.R., Kite, G. 2011. Uncertainty in climate change projections of discharge for the Mekong River Basin. Hydrology and Earth System Sciences 15, 1459-1471. Madsen, H. 2003. Parameter estimation in distributed hydrological catchment modelling using automatic calibration with multiple objectives. Advances in Water Resources 26, 205-216. Singh, C.R., Thompson, J.R., French, J.R., Kingston, D.G., Mackay, A.W. 2010. Modelling the impact of prescribed global warming on runoff from headwater catchments of the Irrawaddy River and their implications for the water level regime of Loktak Lake, northeast India. Hydrology and Earth System Sciences 14, 1745-1765. Thompson, J.R. (in press) Modelling the impacts of climate change on upland catchments in southwest Scotland using MIKE SHE and the UKCP09 probabilistic projections. Hydrology Research.

PhD title:

Climate change and pollution impacts on productivity and biodiversity in the Selenga River Delta: a Siberian, Ramsar wetland of international importance.

First supervisor:

Anson Mackay

Second(other) supervisor(s):

Abstract/outline:

Wetlands provide vital ecosystem services for human populations worldwide through the provision of freshwater, food and biodiversity. Yet these ecosystems are particularly vulnerable to threats from human impact through increasing economic development and population growth leading to habitat modification and excessive nutrient loading. Over the next 100 years, climate change is expected to exacerbate these problems, especially in regions, such as southern Siberia, which has experienced some of the most rapid warming in recent decades. Lake Baikal World Heritage Site is situated in one of the most continental regions of Earth. It contains approximately one fifth of the world’s global resources of surface freshwater, and species living in the lake exhibit high levels of endemicity. Given recent debates on threats to freshwater resources and biodiversity, understanding the functioning of such a complex ecosystem is an important research priority. Over 330 rivers flow into Lake Baikal, the most significant being the Selenga River, which accounts for c. 50% of total annual river inflow. The Selenga River enters Lake Baikal via the Selenga Delta wetlands through a complex array of channels which are active  (ice free) for approximately 6 months of the year. The Delta is the largest in SE Siberia with a mosaic of marshes, reed beds, streams and shallow lakes that extend for over 12,000 km2. It’s seasonally rich bird populations prompted recognition of the area by IUCN and WWF and it was designated a ‘Ramsar’ site in 1994.  The Delta comprises mainly of regularly flooded land, although river branches and lakes are relatively abundant. Habitat heterogeneity is high, leading to high levels of biodiversity. Uniquely, this important wetland plays a vital regulatory role in the ecology of Lake Baikal itself. There are several sources of pollution to the Delta: over 25 villages exist in the area immediately around the Delta itself, several large conurbations lie on the Selenga river, and mining operations are common in the upper catchment. Pollution impact on the Selenga River has increased during the 20th century, resulting in real and potential threat to ecosystem functioning within Lake Baikal. However, what that threat is, is still uncertain, despite a considerable amount of hyperbole surrounding the environmental impacts on ecosystem functioning of the lake. Moreover, confounding stressors, which include climate and hydrological change, and also uncertain. The principal aim of this PhD will be to use high resolution, palaeolimnological techniques to reconstruct pollution and climate impacts on aquatic ecosystem functioning in the Selenga Delta. In our experience, short cores (c. 1m) from the Lake Baikal region span approximately the past 1000 years, a period characterised by distinct changes in climate and more recently human impact. The PhD will involve the following Work Packages: • WP1: characterisation of contemporary water bodies (geography, limnology, biology) in the Delta. The flora and fauna of the Delta are very well characterised, but not microalgae in the lakes, nor possibly water chemistry of the lakes. • WP2: coring of key, selected lakes using gravity and livingstone coring equipment. Upper sediments will need to be dated using radiometric dating (210Pb, 137Cs, 241Am) whereas older sediments will be screened for plant macrofossils with which to undertake AMS 14C dating. • WP3: using lake sediments, reconstruct palaeo food-web using a multiproxy approach, including some or all of the following proxies: diatoms, plant macrofossils, chironomids, cladocera and potentially fish scales. • WP4: using lake sediments, reconstruct recent trends in anthropogenic contamination (heavy metals including mercury; SCPs) • WP5: given the flood-pulse nature of the wetland, mineral magnetic analyses could possibly be used to identify major flood-events through in-washes of clastic materials The work will be closely aligned to a new NERC-funded programme: Silicon isotope records of recent environmental change and anthropogenic pollution from Lake Baikal, Siberia, and will follow on from an existing body of research on Lake Baikal, which has been undertaken in the Department over the past 20 years.

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