The estimation of the magnitude of global temperature change is central for predicting future climate. However, most numerical climate modeling studies have focused on the instrumental period, which covers only a relatively small amount of time (<100 years). To better understand future climate change and to test the robustness of these models, it is important to reconstruct past temperature changes throughout Earth history. This is not a trivial problem, however, because we must rely on proxies of temperature change that often yield ambiguous results. Over the past decades several proxies of past ocean temperature have been developed including palaeoecological transfer functions, Mg/Ca, and biomarkers (Uk'37, TEX86). Among the newest advances in palaeothermometry is the application of "clumped isotopes" which is based on the abundance of 13C-18O bounds in carbonates. The advantage of this method is that the formation of 13C18O16O2 is temperature dependent but independent of the dissolved inorganic carbon and the d18O of seawater. Therefore, the simultaneous measurement of "clumped isotopes" and traditional oxygen isotopes provides a unique solution to the carbonate palaeotemperature equation by constraining both temperature and d18O of water. The Mg/Ca ratio of foraminiferal calcite has been similarly shown to be temperature dependent. Hence, paired measurements of Mg/Ca and oxygen isotopes from the same foraminiferal specimens permit reconstruction of the oxygen isotopes of the sea water. The main aim of the proposal is to combine Mg/Ca and clumped isotope measurements of the same foraminiferal tests to produce independent estimates of temperature. By combining the Mg/Ca and clumped isotopes palaeotemperature equations, the expected relationship between Mg/Ca and clumped isotopes can be predicted. Adherence to the expected relationship in fossil foraminifera will provide confidence in the palaeotemperature estimates or, if they diverge from the expected relationship, will identify problems with either one or both proxies. Initially, we will test the predicted relationship using modern foraminifera which cover a temperature range from approx. 6 to 28 degree to verify and calibrate the method. Next, we will test the application of the method during the last glacial period using a transect of well-dated sediment cores in the north Atlantic. The magnitude of abrupt climate change events during the last deglacial is still under debate in the scientific community. For example, large discrepancies exist in estimates of tropical cooling inferred from marine (~2-4 degree) and terrestrial (~6-10 degree) archives during these extreme events. This discrepancy may be the result of seasonal bias of the temperature proxies. However, the temperature range is much larger than expected for average seasonal temperature differences in the tropics. This raises the question whether these discrepancies are real or caused by differences in the sensitivity or reliability of specific proxies. With tandem measurements of Mg/Ca and clumped isotopes it will be possible to determine the magnitude of temperature change and estimate its spatial extent during abrupt climate change events of the last glacial. Furthermore, the well-dated cores of the late quaternary provide an ideal test case for our tandem Mg/Ca-clumped isotope palaeothermometer whose successful development and application will permit to investigate many relevant open questions about earth's climate history.
Some of the most spectacular data in the recent history of earth science have been derived from the drilling of the polar ice caps. Foremost amongst these is the revelation that the atmospheric CO2 content was about one-third lower (roughly 80ppmV) during the Last Glacial Maximum than during the warmer period of the past 10 thousand years. Thus, it is widely believed that changes in atmospheric CO2 strongly amplified glacial-interglacial climate change. Although a clear explanation has yet to emerge for the observed CO2 decline during glacials and rise during interglacials, mass balance arguments clearly point to the ocean exchange as the primary modulator of the CO2 changes on these time scales. Recent studies have pointed to the Southern Ocean due to the tight coupling between carbon dioxide levels and climate in the southern hemisphere high latitudes. One prevailing model involving the SO envisions that at the end of the last glacial cycle (deglacial) climate reorganisation, the reduction in sea ice cover and strengthening wind fields may have stirred up deep ocean waters rich in carbon and nutrients to the surface releasing CO2 that has been stored in the deep ocean during the glacial period. However, this model presents a paradox. In the modern SO, the physical release of CO2 is roughly compensated by the uptake of carbon by algae during photosynthesis at the sea surface utilising the nutrients that accompany CO2 in the resurfacing deep waters. Therefore for the CO2 release model to work conditions in SO should have been unfavourable for the biological uptake allowing globally significant CO2 efflux to occur. In the proposal we hypothesize that one potential factor that could have constrained biological CO2 uptake in the SO is the dearth of Fe during algal growth. The substantial decline in dust inputs (important source of Fe) during the deglacial recorded in Anatrctic ice cores lends support to this idea. Therefore, we propose to investigate the role of productivity on CO2 efflux from the SO during the last deglaciation by investigating the nature and magnitude of marine productivity, relative macronutrient utilisation (nitrate and silicic acid), micronutrient (Fe & Zn) bio-availability and in a carefully selected set of marine sediment cores covering this period. We propose to apply state-of-art geochemical and isotopic tools recently developed including silicon and nitrogen isotopes as proxies for macronutrient utilisation and diatom-bound trace metals as tracers of Fe and Zn biological availability in combination with more conventional proxies of productivity and dust inputs. By doing so, we propose to address a fundamental and lingering question in Earth System Science- that is "What are the controls on glacial-interglacial CO2 change?"
Density Functional Theory is an atomic scale tool which can be used to learn about the structure and behaviour of substances, especially when atoms or molecules react with one another. For instance, it has been used to tell us about how the structure of water changes when it becomes acid or alkali. It is true to say that it has revolutionised our understanding in many aspects of science, and one of the originators (Walter Kohn) was awarded the Nobel Prize (in 1998) for developing the underlying theory which is at the heart of DFT computer simulation software. Since the first implementation of DFT, several flavours of DFT have been developed that have generally increase accuracy of this method, allowing scientists to calculate energies for chemical reactions with amazing accuracy. The usefulness of this method is increased when computer processors can be utilised in parallel to divide up the calculation into small sub-calculations. Currently Intel are marketing their Duo core processors for desktop and notebook computers where the computer is able to split the computational burden over two processors. The same principle is used on national supercomputers, where over 1000 processors can be used to make very demanding calculations (that would take 1000 years on one processor) into a far more manageable task, taking one year on 1000 processors, assuming the program was perfectly efficient. In reality, it is very difficult to obtain such efficient parallelism / special tricks need to be used to use the computer processor performance. This application seeks funding to develop a popular new piece of software that it can run far more efficiently on the new national supercomputer.Once the develpoment has taken place, we will look in detail at the structure and nanoscopic defects in ice. Understanding the structure and behaviour of microscopic imperfections in the ice structure will lead us to better understand how it conducts but more generally, how these defects influence the stability of ice. The latter is becoming ever more topical and important as we seek to understand how ice melts in order to better estimate the influence of temperature on glacial ice sheet.
With age, we gradually accumulate both environmentally and intrinsically generated defects at different levels in our bodies: from errors in DNA (mutations), proteins (aggregates), organelles (mitochondrial dysfunction) to cells (cancer) and organs (heart failure). Ageing is the largest risk factor for the majority of human diseases in the Western world, including progressive diseases such as Alzheimer's and Parkinson's, diseases like cancer that show variable rates of onset, and catastrophic systems failures such as heart-attack and stroke. While the study of specific ageing-related disease processes has long been a major focus of biomedical and biological research, there is a growing realisation of the importance of analyzing the normal ageing process itself as an essential part of the problem, and of exploring ways to slow or reverse its effects. Ageing is a multi-factorial problem that can be seen as an inevitable feature of the ravages of time and the harmful environments in which organisms live. Recent discoveries, however, demonstrate that ageing can be modified in dramatic ways by relatively simple interventions. For example, single gene mutations and dietary restriction can delay ageing and provide a universal improvement in health late in the life of laboratory animals. Moreover, the pathways involved in ageing are conserved in evolution, and genetic variants in their components are associated with differences in lifespan in humans. A central challenge of ageing research, however, remains to tease out a comprehensive and unified picture of the genetic factors and mechanisms determining longevity. We plan to utilize fission yeast as a model organism to advance our understanding of complex processes with fundamental importance for ageing. Remarkably, many of these processes are now known to be similar from yeast to human. Yeast cells enter a quiescent, non-dividing state under limiting nutrients, and the lifespan in this state depends on both genetic and environmental factors. Such quiescent yeast cells provide a valuable system to analyze basic processes affecting ageing and longevity. We will analyze how the global regulation of genes and proteins is modified during ageing, and how any changes might affect longevity. We will also exploit a collection of all viable gene knock-out mutants to systematically identify those genes that lead to longer or shorter lifespan. We will further examine how lifespan varies among wild yeast strains from different geographical locations, and whether this variation goes with changes in gene expression. Finally, we will integrate these complementary global data sets and follow-up the most promising findings to uncover particular roles of specific genetic factors in cellular ageing and longevity. Importantly, this research will provide a valuable platform to understand the genetic factors involved in ageing in humans, to eventually develop interventions that slow ageing and thus prevent or delay the numerous age-associated diseases.