ESSI PhD Projects 2016 - School of Earth and Environment

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transferable skills within the SPHERES NERC DTP, from computer ... to gain, a good degree in chemistry, geology, environ
ESSI PhD Projects 2016

School of Earth and Environment University of Leeds http://www.see.leeds.ac.uk/research/essi/ @ESSILeeds

Contents Death in the Oceans: extinction risk in the marine realm ......................................................... 2 The Environmental Geochemistry of Vanadium........................................................................ 4 Collapse of the British - Irish Ice Sheet: the role of climate and sea level changes .................. 7 Catastrophic ice melt and life in the oceans............................................................................ 10 Sclerochronology in deep-sea bivalves .................................................................................... 14 Evolution of a habitable planet: An integrated modelling and geochemical study of the rise of oxygen to modern levels ..................................................................................................... 17 Early animals and plants and their effects on the Earth system: Geochemistry and biogeochemical modelling ....................................................................................................... 21 Archives and modelling of ocean sulphate concentrations over the last 200 million years ... 25 Investigating the role of marine sediments in the global oceanic cycling of nutrient trace metals....................................................................................................................................... 29 Nutrient cycling across the Great Oxidation Event: Dynamics, controls and consequences for Earth surface oxygenation ....................................................................................................... 34 Environmental change during the mid-Permian to Permo-Triassic transition in the deep water Karoo Basin, South Africa .............................................................................................. 37 Carbonate Platform Shutdown and the Rise of Black Shale Giants ........................................ 40 Understanding Earth’s Last Interval of Greater Global Warmth ............................................. 42

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Death in the Oceans: extinction risk in the marine realm Supervisors: Tracy Aze , Alex Dunhill and Paul Wignall (School of Earth and Environment, University of Leeds) Contact email: [email protected] Extinction rates are currently at their highest for 65 million years and are rising at an unprecedented rate. Oceanic ecosystems are particularly vulnerable to rapid environmental change, which is compounded by our lack of knowledge regarding the evolutionary history of many marine groups. This project will employ a multidisciplinary approach to provide the most detailed and comprehensive analysis of extinction risk in a marine group to date. The student will use the planktonic foraminiferal fossil record to address extinction risk in the marine realm; the group have an up-to-date species-level phylogeny (Aze et al. 2011) and have the best species-level fossil record of any group throughout the Cenozoic. Planktonic foraminifera are cosmopolitan unicellular biomineralising marine zooplankton that range from tropical to polar latitudes. They are widely used in palaeoceanographic and palaeoclimatic research and as a result there is a substantial literature detailing their ecological preferences. During the Cenozoic, the Earth transitioned from a high atmospheric CO2 greenhouse world to the lower CO2 icehouse conditions of today, resulting in a fossil record that chronicles biological responses to significant environmental perturbations. Figure 1. A scanning electron microscope image of the planktonic foraminifera Globigerinella adamsi, specimen from core material from the GLOW Cruise to the S.W. Indian Ocean. Objectives: The student will use a random sampling approach to identify extinction events as presented in Aze et al. (2011) to determine whether some species are more susceptible to extinction risk than others and whether risk is linked to ecological or morphological traits. The foraminifer fossil record will be analysed for extinction indicators that can be used to predict present-day and future extinction, such as changes in ecology, morphology, abundance or geographic range.

Hypothesis 1: Planktonic foraminifera demonstrate shifts in ecological niche strategy prior to extinction. Through direct sampling of the fossil record, populations will be geochemically analysed for their carbon and oxygen isotopic compositions with a view to identifying ecological niche migrations in the water column prior to extinction. Hypothesis 2: Planktonic foraminifera demonstrate a change in morphology, such as body size dwarfing, prior to extinction. Through direct sampling of the fossil record, populations will be morphometrically analysed to statistically identify changes in body size and shape prior to extinction. Hypothesis 3: Planktonic foraminifera demonstrate geographic range contractions and decreases in abundance prior to extinction. Using fossil occurrence data derived from the NEPTUNE database and IODP records geographic ranges will be reconstructed within a GIS framework and compared with origination, extinction, and diversification rates.

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Potential for high impact outcome This project will represent a significant contribution to our understanding of how changes in global climate can impact an important group of marine calcifiers, which can ultimately be used inform potential conservation efforts aimed at reducing the loss of biodiversity in our global oceans. The work is easily divisible into publications that will form consecutive chapters of the PhD thesis, which can be written up for publication. The first will address: Ecological niche shifts in response to extinction. The second: morphological responses to ecological stress. The third: the effects of geographic range and provinciality on extinction vulnerability. Training This interdisciplinary project will provide the successful PhD candidate with highly valued and sought-after tools for investigating past climates and species interactions and their effects on extinction risk, such as geochemistry, morphometrics, taxonomy and phylogenetic and tatistical modelling. This will equip the student with the necessary expertise to become the next generation of palaeontological and climate scientist, ready to carry out their own programme of innovative scientific research. The student will benefit from working within and collaborating with dynamic scientists within the multidisciplinary Palaeo@Leeds group (Haywood, Little, Newton, Poulton, Wignall). There will be opportunities to present results at major, international conferences, e.g. AGU (San Francisco), EGU (Vienna), GSA, PalAss, and attend residential summer-schools (e.g. in Italy, USA, UK) and in-house workshops and courses. References 

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Aze T., Ezard T.H.G., Purvis A., Coxall H.K., Stewart D.R.M., Wade B.S. and Pearson P.N. (2011) A phylogeny of Cenozoic macroperforate planktonic foraminifera from fossil data, Biological Reviews, 86, pp.900-927. Ezard T.H.G., Aze T., Pearson P.N. and Purvis A. (2011) Interplay between changing climate and species’ ecology drives macroevolutionary dynamics, Science, 332, pp.349-351. Wade, B.S., Twitchett, R.J. (2009). Extinction, dwarfing and the Lilliput effect. Palaeogeography, Palaeoclimatology, Palaeoecology, 284 (1-2), 1-3. doi:10.1016/j.palaeo.2009.08.019

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The Environmental Geochemistry of Vanadium. Supervisors: Ian Burke and Caroline Peacock (School of Earth & Environment, University of Leeds) Contact email: [email protected] On the one hand, vanadium is an important component of steel and an emerging technical element, which in the form of an electrochemical redox battery might eventually power our cities. On the other hand, all vanadium compounds are toxic and potentially highly mobile in the environment. The occurrence of vanadium in the environment is increasing due to its concentration in fossil fuel residues and several important metal processing wastes (e.g. V is enriched in several types of crude oil and their combustion residues can become highly enriched in V; wastes from steel and aluminium production both concentrate V from the primary ores and leaching of V is a big issue for handling and disposal of these wastes; Chaurand et al., 2007 and Burke et al., 2012). Add to this the potential of vanadium for redox batteries and vanadium pollution could soon be a global environmental concern. There is currently a severe lack in our basic understanding of the environmental geochemistry of this important element and emerging pollutant, in low temperature freshwater, soil and sedimentary environments. These are precisely the environments where vanadium is easiest to extract from host rocks, and set to do the most environmental damage. Because vanadium is an important technical metal, concerns over long-term security of supply have made recovery and recycling of vanadium a significant issue for both environmental protection and economic benefit. It is essential that we understand the behaviour of vanadium in the critical zone so that its mobility, hazard and concentrations can be predicted (and potentially exploited during recovery schemes). The aim of this project is to discover and describe the processes responsible for the reaction and release of vanadium from soils and sediments in the natural environment. Understanding these processes will aid efficient, low energy extraction technologies for vanadium, and provide the basic knowledge, so far lacking, to predict, control and remediate vanadium pollution in the critical zone. Vanadium exists in multiple oxidation states (in the natural environment V(IV) and V(V) are the most important) and its environmental behavior is governed by a complex interplay between redox, sorption to minerals and organic complexation processes. Previous work has considered vanadium’s interactions with single minerals in lab experiments and models (Wehrli and Stumm, 1989; Peacock and Sherman, 2004) but no work has yet considered the full complexity of processes that are likely in surface and near surface environments. It is therefore vital to build a novel understanding of how vanadium is enriched in the solids present in water-soil systems, how vanadium reacts with soil minerals (and the effect of organic matter on these reactions), and to predict how vanadium may be released to solution during recovery procedures. This project, therefore, will seek to use a combination of experimental, theoretical and spectroscopic approaches to determine the fundamental mechanisms that control the Figure. 1 Open University YouTube clip showing the various and colourful oxidation states of vanadium. https://www.youtube.com/watch?v=sFAGQL okym4&feature=youtu.be 4

environmental mobility of vanadium in water-mineral systems. The project will focus on the interaction of aqueous vanadium species with several important soil minerals (e.g. metal oxides, clays) at a range of environmentally relevant pH, redox states and ligand availabilities. Objectives The specific objectives of the work are to: 1. Determine the sorption behaviour of V(V) and V(IV) species in the presence of iron oxide and clay minerals at the macro and molecular scale at a range of environmentally relevant conditions (e.g. pH, V concentration and redox state). 2. Investigate the effects of competitive sorption processes on V behaviour in soil-water systems containing elevated concentrations of (dissolved) organic matter and mixtures of minerals. 3. Determine the effect of sample aging on the reversibility of V uptake to solids to aid prediction of the potential for V recovery from affected systems.

Figure. 2 Examples of environments affected by industrial wastes that contain elevated concentrations of soluble V species. Discovering the fate of V in such environments will be the key to predicting environmental harm and the potential to recover and recycle the V present.

Figure 3. Diamond Light source in Oxfordshire: a powerful new facility for molecular level studies of contaminant behavior and an example of the molecular bonding proposed for V(V) on an iron oxide surface (from Peacock and Sherman, 2004). It is only when the molecular behaviour is understood that large-scale environmental predictions can be made with certainty. 5

Training You will work under the supervision of Dr. Ian Burke and Dr. Caroline Peacock within the Cohen Geochemistry Group at Leeds. You will receive specialist scientific training in state-of-the-art geochemical, mineralogical, experimental and analytical techniques and computational geochemical modelling. In addition, you will have the opportunity to be trained in a wide variety of key transferable skills within the SPHERES NERC DTP, from computer programming and modelling, to media skills and public outreach. You will also be encouraged and supported to present your research at national and international scientific conferences. Eligibility The applicant must satisfy the requirements to register as a doctoral student at the University of Leeds, which involves holding appropriate Honours, Diploma or Masters Degree and having passed the appropriate English language tests. Applications are invited from graduates who have, or expect to gain, a good degree in chemistry, geology, environmental science, materials science, chemical engineering or another relevant science discipline. Relevant Masters level qualifications are also welcomed. The applicant should have a good command of both written and spoken English. Suggested Reading (copies available on request)    

Wehrli B. and Stumm W. Vanadyl in natural waters – Adsorption and hydrolysis promote oxygenation. Geochimica et Cosmochimica Acta. 1989, 53(1), 69−77. Peacock C. L. and Sherman D. M. Vanadium(V) adsorption onto goethite (alpha-FeOOH) at pH 1.5 to 12: A surface complexation model based on ab initio molecular geometries and EXAFS spectroscopy. Geochimica et Cosmochimica Acta. 2004, 68(8), 1723−1733. Chaurand P., Rose J., Briois V., Olivi, L., Hazemann J. L., Proux O.; Domas, J.; Bottero, J.-Y. Environmental impacts of steel slag reused in road construction: A crystallographic and molecular (XANES) approach. Journal of Hazardous Materials. 2007,139(3), 537−542. Burke I. T., Mayes, W. M., Peacock C. L., Brown A. P., Jarvis A. P. and Gruiz, K. Speciation of arsenic, chromium and vanadium in red mud samples from the Ajka spill site, Hungary. Environmental Science and Technology. 2012, 46, 3085-3092.

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Collapse of the British - Irish Ice Sheet: the role of climate and sea level changes Supervisors: Lauren J Gregoire1, Dave Hodgson1, Chris Clark2, Claire Mellett3 1

(School of Earth and Environment, University of Leeds) (University of Sheffield) 3 (British Geological Survey) 2

Contact email: [email protected] This project will use the latest generation of ice sheet models and a new reconstruction of the retreat of British and Irish ice sheet to understand what drives the collapse of marine influenced ice sheets. Extra stipend and research funding will be provided through a partnership with the British Geological Survey. The largest threat to future sea level rise is the potential collapse of the marine–influenced West Antarctic Ice Sheet. The same processes that could cause up to 5 m sea level rise over the coming centuries were at play at the end of the last ice age and drove the collapse of the British - Irish and Scandinavian Ice Sheet (Figure 1). This ice sheet is becoming the best constrained anywhere in the world thanks to new data from the ongoing BRITICE-CHRONO project, and can serve as a test for ice sheet models that we use to project future sea level changes. And, even more excitingly, this large collection of data can be combined with the latest ice sheet models to Figure 1: Reconstruction of the BritishIrish ice sheet 27,000 years ago. understand what drives ice sheet collapse. Marine-influenced ice sheets (where portions of the ice sheet is based below sea level) can retreat and in some cases be destabilized by atmosphere and ocean warming and sea level rise. Yet as the ice sheet loses mass, the gravitational pull it exerts on the ocean reduces, which results in a sea level fall at the ice margin, potentially stabilising the ice sheet (Gomez et al., 2010). Such processes are currently being implemented in BISICLES (Cornford et al., 2013), the most efficient of the latest generation of ice sheet models. What makes BISICLES stand out from other complex ice sheet models is its ability to increase its resolution where and when it is needed (Figure 2). This allows us to make efficient and accurate simulations of marineinfluenced ice sheets. Simulating the British Irish and Scandinavian Ice Sheets with BISICLES will allow us to test these latest model Figure 2: Example of BISICLES model output. The developments. model uses an adaptive grid to enable efficient and BRITICE-CHRONO is a large research project with accurate simulation of marine ice sheets like the over 40 researchers lead by Prof Chris Clark (co- British-Irish ice sheet. supervisor of this project) aimed at reconstructing the rate and patterns of retreat of the British-Irish Ice Sheet. In the past three years, 7

researchers have undertaken two research cruises and over 300-person days of fieldwork to collect material (sand, shells, rock) for dating ice sheet retreat. The 800 new dates on retreat along with existing data will be used to build an empirical reconstruction of the collapse and retreat of the ice sheet. Additionally, initial modelling of the ice sheet is being performed with models less complex than BISICLES. These numerical experiments will be used as a starting point for this project. Furthermore, an extensive set of subsurface data is available from the CASE partner, the British Geological Survey, to help further refine and constrain ice margin positions and the dynamic interaction between the British and Scandinavian ice sheets. Objectives In this project, you will use the last generation BISICLES ice sheet model combined with the new and extensive BRITICE-CHONO dataset to understand the extent to which ice retreat is driven by fluctuations in sea level and how much of the BIIS retreat was driven by ocean and atmosphere warming. The project will aim to answer the following questions: 1. How well can the BISICLES ice sheet model simulate the British-Irish ice sheet deglaciation? 2. What were the relative roles of ocean and atmosphere warming and sea level changes in driving ice retreat? 3. How did ice dynamics and the rate of retreat change when the ice sheet retreated onto land? 4. Optional: How did varying tidal ranges tides influence the stability of ice cover and rates of retreat? A by-product of the modelling investigation will be to learn which parts of the ice sheet were most sensitive to change. This guides us to where fieldwork is most needed to further constrain the timing of retreat. In the latter parts of the project fieldwork at some of these sites could be undertaken. Potential for high impact Understanding marine ice sheet retreat is of great relevance to current and future sea level changes as it is the largest threat to future sea level change. This project will, for the first time, test the ability of complex ice sheet models to simulate past marine ice sheet retreat. It will also provide a better understanding of the processes that drive ice sheet collapse and could lead to model development that would improve future sea level projections. The novelty of the ice sheet techniques and dataset used provides this project with great potential for making exciting scientific discoveries. Training This interdisciplinary project will provide the successful PhD candidate with highly valued and sought-after skills in numerical ice sheet modelling, a deep understanding of marine and terrestrial geology and a broad knowledge of the Earth System. This will equip the student with the necessary expertise to become a next generation glaciologist, ready to carry out their own programme of innovative scientific research. The student will benefit from working within the dynamic and multidisciplinary Palaeo@Leeds, Physical Climate Change research groups and Sedimentology research groups; as well as collaborating with the BRITICE-CHRONO team and other international experts in ice dynamics, palaeoclimate, ice sheet reconstruction and sea level rise. There will be opportunities to present results at major, international conferences, e.g. AGU (San Francisco), EGU (Vienna) and attend residential summer-schools (e.g. in Italy, USA, UK) and in-house workshops and courses. CASE Partner The British Geological Survey will be a partner for this project and provide extra funding additional to the NERC student stipend. This partnership will also provide access to extensive datasets that will be used to constrain and improve the numerical modelling. 8

Entry requirements A good first degree (1 or high 2i), or a good Masters degree in a physical, mathematical or geological discipline, such as mathematics, physics, geophysics, engineering or meteorology. Experience in programming (eg. Fortran, Matlab, python, C …) is of advantage. Further information Watch:  

Modelling ice sheet retreat (http://www.egu.eu/medialibrary/video/1497/simulation-ofthe-amundsen-sea-embayment-over-three-centuries-of-sustained-retreat-video/) Reconstructing the British-Irish ice sheet: (https://www.youtube.com/watch?v=3v1_ed4dJ04&feature=youtu.be)

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Reconstructing the British-Irish ice sheet (BRITICE-CHRONO) (http://www.briticechrono.org/) Short story about the BISICLES ice sheet model (http://crd.lbl.gov/news-andpublications/news/2013/berkeley-code-captures-retreating-antarctic-ice/) , Marine ice sheet instability,(http://www.antarcticglaciers.org/glaciers-and-climate/iceocean-interactions/marine-ice-sheets/ ) Rapid sea level rise triggered by ice saddle collapse, (http://planetearth.nerc.ac.uk/news/story.aspx?id=1254&cookieConsent=A) Clark, C.D. et al. 2012. Pattern and timing of retreat of the last British-Irish Ice Sheet. Quaternary Science Reviews, 44, 112-146. Cornford, S. L. et al. 2015. Century-scale simulations of the response of the West Antarctic Ice Sheet to a warming climate, The Cryosphere, 9, 1579-1600. Gregoire, L.J., et al. 2012. Deglacial rapid sea level rises caused by ice-sheet saddle collapses. Nature 487, 219–222. Gomez N. et al. 2010. Sea level as a stabilizing factor for marine-ice-sheet grounding lines. Nature Geoscience 3, 850–853.

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Catastrophic ice melt and life in the oceans Supervisors: Ruza Ivanovic1, Fanny Monteiro2, Jon Hawkings2, Jemma Wadham2, Laura Robinson3, Andrew Shepherd1 Collaborators: Lauren Gregoire1, Andrew Wickert3 1

School of Earth and Environment, University of Leeds, UK School of Geographical Sciences and 3School of Earth Sciences, University of Bristol, UK 3 Department of Earth Sciences, University of Minnesota, USA 2

Contact email: [email protected] This project combines cutting edge knowledge of ice sheet dynamics and biogeochemistry with state of the art ocean modelling. The aim of the PhD is to examine the influence of catastrophic meltwater discharge on physical ocean circulation, ocean biogeochemistry and marine ecosystems since the Last Glacial Maximum (21 thousand years ago) and in the future. Scientific background

Figure. 1 Meltwater routing from simulated North American Ice Sheet evolution (Gregoire et al., 2012) and high resolution modelling of the Atlantic and Arctic Oceans (Condron and Winsor, 2012). Melt from the Greenland and Antarctic ice sheets is an important source of nutrients for the [sub]polar oceans, and accelerated ice melt in the future could significantly influence marine productivity, directly affecting planktonic life at the base of the food chain, with knock-on consequences for marine ecosystems and the carbon cycle. Through its effect on ocean primary productivity, nutrient-loaded ice melt has great potential to change deep sea carbon export; one of the most effective mechanisms for locking carbon away from the atmosphere (referred to as the biological pump). From geological evidence, we know that there have been several episodes of catastrophic ice melt since the Last Glacial Maximum (21 thousand years ago) as climate warmed and the vast ice sheets that once covered the northern continents disintegrated. For example, around 14.5 thousand years ago, the collapse of the North American ice sheet (e.g. Figure) is thought to have contributed towards a global sea level rise of up to 22 m in just a few centuries (Meltwater Pulse 1a), scouring the landscape as meltwater drained to the oceans. We hypothesise that such extreme changes in the discharge of glacial meltwater must have dramatically influenced nutrient delivery to the oceans. The question is how did these surges in glacial melting affect marine life and deep sea carbon export? With the support of a supervisory team and collaborators who are experts in ice sheet dynamics, meltwater routing, glacial nutrient export, and numerical modelling of marine ecosystems, ocean circulation and climate, the student will be uniquely positioned to answer this important question. 10

Furthermore, the methods developed to carry out this research can be applied to future scenarios of ice melt to better understand how our own world will change through time. Project Aim To understand the effect of catastrophic meltwater discharge on physical ocean circulation and marine ecosystems during the last 21 thousand years and in the future. This will be achieved by combining different knowledge and skills for researching climate processes, ice sheet evolution, ocean biogeochemistry and numerical modelling. Research objectives 1. To simulate the influence of deglacial meltwater pulses on ocean circulation. This will use the latest meltwater routing scenarios from 21 thousand years ago to present, and the wellestablished high resolution MIT General Circulation Model (MITgcm). 2. To infer the surface climate signal from modelled changes in ocean circulation. Using the simulations produced through objective 1, this will be based on emerging simulations from the internationally coordinated Palaeoclimate Modelling Intercomparison Project 4 (Last Deglaciation Working Group). 3. To examine the effect of nutrient-bearing continental freshwater discharge on marine productivity, carbon export and ecosystems. This will also build on objective 1, using a selection of the MITgcm physical ocean circulation experiments and running them with the Darwin ecosystem model. 4. To explore the effect of projected future ice [sheet] melt on ocean circulation and ecosystems. This will use ice sheet evolution scenarios such as those projected using the RACMO model, run through the MITgcm and Darwin ecosystem model. Potential for high-impact research This novel work presents an exciting opportunity to understand how the Earth’s cryosphere influences the ocean, its ecosystems and the climate; and what changes may be brought upon these important domains in the future. The student will be integrated into a very collaborative field of research, with a widespread network of scientists working at the forefront of their disciplines. By carrying out interdisciplinary research that forges cutting-edge understanding of Earth System science, the student will develop a highly sought-after, multidisciplinary skill set in state-of-the-art techniques. By the well-networked nature of this work, and due to its timeliness, there is strong potential for the PhD candidate to influence the direction of international research being carried out on this theme, and to thus establish a world-renowned reputation for innovative science. Training, support and research opportunities This project affords many exciting opportunities for skills and research development, putting the student in a strong position to pursue an academic career afterwards and which are also highly transferable to non-academic jobs, in particular:   

Working within the dynamic and multidisciplinary Palaeo@Leeds and Cohen Geochemistry research groups, the Institute for Climate and Atmospheric Studies and the Earth Surface Science Institute. Using state-of-the-art research facilities; high-performance computer clusters at the University of Leeds, and ‘clean’ and mass-spectroscopic laboratories at the University of Bristol. Developing high-tech computer programming, model output processing and data visualisation skills, with the support of scientists across the School of Earth and Environment, Leeds and School of Geographical Sciences, Bristol who have a long track record of training highly successful PhD students with limited prior knowledge of computing.

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Collaborating with world-leading experts in Bristol (UK), Minneapolis (USA) and MIT (Boston, USA). Attending and presenting results at major, international conferences, e.g. AGU (San Francisco), Goldschmidt (Europe & N. America) and EGU (Vienna). Attending residential summer-schools (e.g. in Italy, UK) and in-house workshops/courses. Taking part in the internationally coordinated Palaeoclimate Modelling Intercomparison Project (PMIP) Last Deglaciation Working Group.

Full-support for all technical and scientific aspects of the project, including the model development work, will be provided in-house (Leeds) and by the external collaborators (Bristol, Minnesota). With this training, the student will be well equipped to pursue their own research interests. Entry requirements A good first degree (1 or high 2.1), Masters degree or equivalent in a physical or mathematical discipline; such as Physics, Mathematics, Meteorology, Climate Sciences, Earth/Environmental Sciences, Chemistry, Engineering or Computer Sciences. Some experience of computer programming is also highly desirable e.g. in Fortran, C++, Python, MATLAB, IDL or R etc... Further information 

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Some YouTube videos: Reconstructing climate history, (https://www.youtube.com/watch?v=PfjkeEABGI), Surface ocean circulation (https://www.youtube.com/watch?v=xusdWPuWAoU), Drivers of ocean circulation. (https://www.youtube.com/watch?v=vP4QTyVQTUo) Condron, Alan, and Peter Winsor. 2012. “Meltwater Routing and the Younger Dryas.” Proceedings of the National Academy of Sciences 109 (49): 19928–33. Death, R., J. L. Wadham, F. Monteiro, A. M. Le Brocq, M. Tranter, A. Ridgwell, S. Dutkiewicz, and R. Raiswell. 2014. “Antarctic Ice Sheet Fertilises the Southern Ocean.” Biogeosciences 11 (10): 2635–43. Dutkiewicz, Stephanie, Jeffrey R. Scott, and M. J. Follows. "Winners and losers: ecological and biogeochemical changes in a warming ocean." Global Biogeochemical Cycles 27.2 (2013): 463-477. Follows, Michael J., Stephanie Dutkiewicz, Scott Grant, and Sallie W. Chisholm. 2007. “Emergent Biogeography of Microbial Communities in a Model Ocean.” Science 315 (5820): 1843–46. Gregoire, Lauren J., Antony J. Payne, and Paul J. Valdes. 2012. “Deglacial Rapid Sea Level Rises Caused by Ice-Sheet Saddle Collapses.” Nature 487 (7406): 219–22. Hawkings, J.R., J.L. Wadham, M. Tranter, E. Lawson, A. Sole, T. Cowton, A.J. Tedstone, et al. 2015. “The Effect of Warming Climate on Nutrient and Solute Export from the Greenland Ice Sheet.” Geochemical Perspectives Letters, 94–104. Hawkings, Jon R., Jemma L. Wadham, Martyn Tranter, Rob Raiswell, Liane G. Benning, Peter J. Statham, Andrew Tedstone, Peter Nienow, Katherine Lee, and Jon Telling. 2014. “Ice Sheets as a Significant Source of Highly Reactive Nanoparticulate Iron to the Oceans.” Nature Comms.. Lenaerts, Jan T. M., Dewi Le Bars, Leo van Kampenhout, Miren Vizcaino, Ellyn M. Enderlin, and Michiel R. van den Broeke. 2015. “Representing Greenland Ice Sheet Freshwater Fluxes in Climate Models.” Geophysical Research Letters 42 (15): 2015GL064738. Monteiro, F. M., M. J. Follows, and S. Dutkiewicz. 2010. “Distribution of Diverse Nitrogen Fixers in the Global Ocean.” Global Biogeochemical Cycles 24 (3): GB3017. Wadham, J. L., R. De’ath, F. M. Monteiro, M. Tranter, A. Ridgwell, R. Raiswell, and S. Tulaczyk. 2013. “The Potential Role of the Antarctic Ice Sheet in Global Biogeochemical 12



Cycles.” Earth and Environmental Science Transactions of the Royal Society of Edinburgh 104 (01): 55–67. Wickert, Andrew D., Jerry X. Mitrovica, Carlie Williams, and Robert S. Anderson. 2013. “Gradual Demise of a Thin Southern Laurentide Ice Sheet Recorded by Mississippi Drainage.” Nature 502 (7473): 668–71.

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Sclerochronology in deep-sea bivalves Supervisors: Crispin Little1, Fiona Gill1, Robert Newton1, Adrian Glover2 Jon Copley3. 1

(School of Earth and Environment, University of Leeds) (Life Sciences, Natural History Museum, London) 3 (School of Ocean and Earth Science, Southampton) 2

Contact email: [email protected] The area of seabed beyond the continental shelves makes up one of the largest of the Earth’s ecosystems. However, the deep-sea benthos is very poorly understood, in large part because the relative inaccessibility of the environment. What is known is that deep-sea communities are diverse, heterogeneous in their composition and contain both generalist and specialist organisms, such as those living in particularly challenging locations, like hydrothermal vents. The life histories of most deep-sea animals are enigmatic. For example, knowledge of growth rates for most species is lacking, as is the extent to which these rates might be influenced by distant external factors, such as photic zone productivity and tidal effects. These life history questions are not esoteric because the deepsea environment is being increasingly impacted by human activities, both indirectly through changes in the climate system, and directly through current and planned exploitation of marine resources. For example, the first machines for commercial mining of deep-sea hydrothermal vent fields are now being constructed, and in the past two years the UK Government has acted as the Sponsoring State to an International Seabed Authority authorised commercial exploration licence for polymetallic nodules over 118,000 square kilometres of the central Pacific abyssal seafloor. Further, deep-sea fisheries are expanding the range and depth of their operations, as is the hydrocarbons industry. All these commercial operations will increasingly impact the deep-sea environment, and questions about the duration of post-mining ecological recovery or the extent of potential set-aside areas are hampered by a general lack of data about deep-sea animals. Studying growth rates of most these animals will be difficult, as traditional methods used in shallow waters, such as mark and recapture, or aquarium studies are not technologically feasible. However, shell-forming deep-sea animals, principally molluscs, are amenable to growth studies, because the shell is an archive of past growth (Figure 1), and can also be preserved into the fossil record, unlike the soft parts of an animal. The study of the growth of shells – sclerochronology – has been widely applied to bivalve molluscs, and has proven to be useful to elucidate many aspects of the biology and ecology of individual animals, including determining the age and growth rate, seasonal temperature extremes, and times of food scarcity or annual reproduction cycles. Further, shell geochemical data (stable carbon and oxygen isotopes, trace and minor element ratios) can also provide proxy information for environmental and physiological conditions during the life of the animal (e.g. Lartaud et al. 2010, Richardson, 2001). So far, sclerochronological techniques have been largely confined to shallow water bivalves (e.g. oysters and scallops), and there have been few studies on deep-sea species. These few studies have shown both fast (e.g. Nedoncelle et al. 2013 and Schöne et al. 2005 for hydrothermal vent mussels) and very slow (centuries) growth rates (e.g. Wisshak et al. 2009 for deep-sea oysters) for deep sea bivalves, indicating the need for further study to better understand the variation in this fundamental aspect of biology of these animals

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Figure 1: Growth lines in deep-sea hydrothermal vent mussel shells revealed in SEM (top) and using Mutvei’s solution (bottom). Both images from Nedoncelle et al. (2013). Aims and objectives: The project will provide essential new information about the growth of bivalves from a wide variety of deep-sea environmental settings, including:   

Hydrothermal vents and polymetallic nodule fields, targeted for imminent commercial exploitation. Lophelia coral reefs, which are particularly vulnerable to deep-sea fishing pressure. Deep-sea sedimented sites that may be affected by future climate-induced warming.

Established sclerochronological imaging and geochemical techniques (see reference list) will be used to analyse a wide range of bivalves from existing museum and personal collections. Fossil shells from similar palaeoenvironments may also be investigated. However, the small, fragile shells of many deep sea bivalves will necessitate the modification of some existing methodologies, with the potential to develop new approaches, as appropriate. Mathematical processing (e.g. spectral analysis) of analytical results will be an essential component of the research, therefore applicants require strong mathematical skills, as well as a background in a relevant discipline. Potential for high impact outcome The project address several aspects of NERC societal challenges, including ‘benefiting from natural resources’ because the deep-sea is currently being targeted as an area for minerals exploitation, and ‘managing environmental change’ as the potential effects of deep-sea mining are currently poorly understood, with much of the necessary base line information still lacking. Further, increasing evidence shows that even the deep-sea is not immune from anthropogenic climate change effects. 15

While sclerochronology has been widely used for shallow water molluscs, the application of the technique to deep-sea species is in its infancy, partly because of the difficulty in obtaining specimens, so the research is likely to yield impactful science. Outcomes from this research are likely to be relevant to government policy on regulation of the so-called ‘blue economy’. Training The student will work within the Earth Surface Science Institute (ESSI) under the supervision of Dr. Crispin Little (palaeo@leeds research group), with additional support from Dr. Robert Newton and Dr. Fiona Gill (both palaeo@leeds and Cohen geochemistry research groups). Project partners Dr. Adrian Glover (Life Sciences, Natural History Museum, London) and Dr. Jon Copley (School of Ocean and Earth Science, Southampton) will provide relevant specimens for study, expertise in deep-sea ecology and sclerochronological analysis, as well as hosting research visits to those institutions. Other project partners, including in France and Portugal have been contacted to provide additional specimens. As a member of two research groups within ESSI, the student will have access to a broad spectrum of relevant expertise, which will be supplemented by an extensive range of research and personal development workshops delivered by the University of Leeds, from numerical modelling, through to managing your degree, and preparing for your viva (http://www.emeskillstraining.leeds.ac.uk/). References     

Nedoncelle, K., Lartaud, F., de Rafelis, M., Boulila, S.,Le Bris N. (2013) A new method for high-resolution bivalve growth rate studies in hydrothermal environments. Mar. Biol. 160:1427–1439. Richardson, C.A. (2001) Molluscs as archive of environmental change. Oceanogr. Mar. Biol. 39:103–164. Schöne, B.R., Giere, O. (2005) Growth increments and stable isotope variation in shells of the deep-sea hydrothermal vent bivalve mollusk Bathymodiolus brevior from the North Fiji Basin, Pacific Ocean. Deep Sea Res. Part I 52:1896–1910. Schöne, B.R., Dunca, E., Fiebig, J., Pfeiffer, M. (2005) Mutvei’s solution: an ideal agent for resolving microgrowth structures of biogenic carbonates. Palaeogeogr. Palaeoclimatol. Palaeoecol. 228:149–166. Wisshak, M., López Correa, M., Gofas, S., Salas, C., Taviani, M., Jakobsen, J., Freiwald, A. (2009) Shell architecture, element composition, and stable isotope signature of the giant deep-sea oyster Neopycnodonte zibrowii sp. n. from the NE Atlantic Deep-Sea Research Part I: Oceanographic Res. Pap.56: 374-407.

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Evolution of a habitable planet: An integrated modelling and geochemical study of the rise of oxygen to modern levels Supervisors: Benjamin Mills1, Simon Poulton1, Tim Lenton2 1

(School of Earth and Environment, University of Leeds) (University of Exeter)

2

Contact email: [email protected] Oxygen is essential for all animal life, and an oxygen-rich atmosphere was likely an essential precursor to the development and diversification of complex life. On Earth, oxygen currently constitutes 21% of the atmosphere, and is thought to have remained within 10-35% over the last 541 million years (the Phanerozoic Eon). However, the preceding geological Eon, the Proterozoic, was characterised by significantly lower atmospheric oxygen (