Methanol is the second most abundant volatile organic compound in the atmosphere, with the majority of this methanol being produced as a waste metabolic by-product of the growth and decay of plants. There is a large disparity between the amount of methanol estimated as being produced and that which enters the atmosphere. This disparity is believed to be due to the utilisation of methanol by plant associated methylotrophs. The diversity and activity of methylotrophs associated with the root and rhizosphere of pea and wheat plants was assessed through a range of cultivation independent and dependent approaches. Enrichments performed with a range of environmental samples supplemented with methanol resulted in the isolation of several strains of methylotrophic bacteria, including two novel species of methylotroph belonging to the family Methylophilaceae, whose genomes were sequenced and their physiological capabilities assessed. The diversity and abundance of methanol dehydrogenase encoding genes in bulk soil and the pea and wheat rhizosphere was assessed through 454 sequencing and qPCR respectively. Sequencing showed high levels of diversity of methylotrophic bacteria within the bulk soil and also showed a shift in this diversity between the bulk soil and the plant associated soils, in spite of no shift in the abundance of these genes occurring. Active methylotrophs present in the bulk and plant associated soils were identified by DNA stable isotope probing using 13C labelled methanol. Next generation sequencing of the 16S rRNA genes and construction of metagenomes from the 13C labelled DNA revealed members of the Methylophilaceae as highly abundant in all of the soils. A greater diversity of the Methylophilaceae and the genus Methylobacterium were identified as active in the plant associated soils relative to the bulk soil. A 13CO2 stable isotope probing experiment identified methylotrophs as utilising plant exudates in the pea and wheat root and rhizosphere communities. Several methylotrophic genera were identified as exudate utilising, in addition to heterotrophic genera and Actinomycetes. The specific 13C labelled genera were shown to vary between both the wheat and pea plants and between the rhizosphere and root communities.

Understanding source and sink process of atmospheric species can help to constrain budgets of gases which contribute towards ozone destruction and warming of the Earth’s atmosphere. The use of isotope ratio analysis is a key tool in budget quantification. GC-MS techniques allowed quantification of δ(37Cl) of CFC-11, CFC-12 and CFC-113 deeper in the stratosphere than previously recorded. Isotope enrichment increased with decreasing mixing ratios for all CFCs. A maximum 37Cl enrichment in CFC-12 significantly exceeded that published to date. Apparent isotope fractionation (εApp ) varied with respect to latitude for 37Cl analysis. The first measurements of δ(13C) of CFC-11, CFC-12 and CFC-113 at stratospheric altitudes displayed increasing enrichment with altitude. Minimal correlation was observed between latitude and apparent isotope fractionation. Values of εApp are significantly lower than that given by fractionation observed in laboratory photolysis experiments. Reanalysis of samples which had undergone photolysis allowed measurements to be linked to an internationally recognised 13C scale (VPDB) allowing direct comparison between photolysis rates of CFC-12 analysed using different analytical systems. Based on the mass difference, the isotope fractionation of 17O should be approximately half as much as that of 18O, with respect to 16O. The proportion of 17O in tropospheric air is in fact higher. Identifying the source of the 17O excess would identify possible non-mass dependent fractionation in sources or sinks. The development of an IR-MS measurement system allowed for the first measurements of Δ17O in stratospheric N2O above 12 km altitude. The data suggest that photolysis and reaction with O(1D) are not the source of the 17O anomaly. The newly developed system allowed participation in an interlaboratory compatibility study. Development of a measurement system capable of analysis of 37Cl in CH3Cl allowed analysis of test gas preparations of CH3Cl in preparation for air concentrate analysis. The first steps towards the synthesis of a calibration gas of characterised isotopic composition were carried out.

The changing structure of the marginal sea-ice zone (MIZ), together with high temperature gradients between the cold Arctic air and relatively warm sea water, contribute to uncertainty in numerical weather prediction (NWP). Since cold-air outbreaks (CAO) over the MIZ contribute strongly to heat transfer in the polar areas, assessment of variability in them is of a great importance. This thesis deals with extending our understanding of the variability within CAO by means of large eddy simulations, performed in The Met Office Large Eddy Model (LEM). The novel approach of this study lies within: Firstly, introducing three different patterns of heterogeneity in surface temperatures that represent conditions in MIZs; secondly, investigating both the spatial and temporal variability in the developing boundary-layer convection. A set of idealised scenarios and a case study are analysed. The case study is performed for a weak CAO event observed during ACCACIA field campaign on 21 March 2013. The study shows a profound impact of the inhomogeneous surface on both the spatial organisation of the boundary-layer convection and the latent heat flux at the surface and the boundary layer. The effect of heterogeneities depends strongly on the wind shear, the size and the orientation of the heterogeneity, and the initial stratification. When active cumuli clouds form, the effect of heterogeneities quickly diminish due to a top-driven mixing. In a stronger stratification that inhibits cumulus formation, the effect of heterogeneity is maintained. Stripes of temperature anomalies parallel to mean wind direction drive the formation of forced convective rolls and facilitate significantly higher latent heat flux. The impact of this heterogeneity usually increases with increased wind-shear, while the impact of other heterogeneities generally decreases. The impact of temperature heterogeneity is generally stronger than the impact of varying ice roughness. The implications for the parametrization of convective boundary layer are discussed.

Glaciers within the Amundsen Sea Embayment (ASE) are rapidly retreating and so contributing »10% of current global sea level rise, primarily through basal melting. Here the focus is atmospheric features that influence the mass balance of these glaciers and their representation in atmospheric models. New radiosondes and surface-based observations show that global reanalysis products contain relatively large biases in the vicinity of Pine Island Glacier (PIG), e.g. near-surface temperatures 1.8 ±C (ERA-I) to 6.8 ±C (MERRA) lower than observed. The reanalyses all underestimate wind speed during orographically-forced strong wind events and struggle to reproduce low-level jets. These biases would contribute to errors in surface heat fluxes and thus the simulated supply of ocean heat leading to PIG melting. Ten new ice cores show that there is no significant trend in accumulation on PIG between 1979 and 2013. RACMO2.3 and four global reanalysis products broadly reproduce the observed time series and the lack of any significant trend. The zonal pressure gradient between the Amundsen Sea and the Antarctic Peninsula is the main driver of variability in accumulation on PIG. Finally, the meteorological conditions associated with high heat flux events within coastal polynyas in the ASE are investigated. In three case studies high resolution simulations produce turbulent heat fluxes that are 10-20% (up to 100 W m¡2) larger than those in coarse resolution simulations. Representation of a hydraulic jump at the base of a slope is the key driver of the increased heat fluxes in a polynya close to PIG, with its presence leading to large differences in surface fluxes in the simulations. Overall it is shown that moving towards using higher resolution atmospheric products will both reduce the magnitude of coastal biases near PIG in reanalysis products, and allow complex orographic flows, important to coastal polynya processes, to be more adequately resolved.

Climate change while associated with change a in the mean climate also presents itself as a change in the variance of climate, resulting in an increase in the number of extreme climatic events (ECEs). Increased numbers of hot days, droughts and extreme precipitation events are all predicted under future climate scenarios. To date, there is very little understanding as to the potential effects that this may have on biodiversity. In order to model the future impacts of ECEs on biodiversity and to inform conservationists about the most appropriate mitigation strategies, we need to understand how ECEs have impacted species in the past, which species are sensitive and why? Finally, can factors such as habitat and topography play a role in reducing the impact of ECEs? This thesis aims to advance the knowledge relating to the above questions by examining their impact on UK butterflies, a bioindicator group. This study developed a novel approach to identifying statistically identified, biologically relevant ECEs (heat, cold, precipitation and drought). Research into the impact of ECEs on yearly population change, localised declines and widespread decline events, identified that UK butterflies are particularly vulnerable to extreme heat during the overwintering phase, while tUK butterflies find extreme heat beneficial during their adult phase and finally are negatively impacted upon by precipitation extremes during their adult life stage. Chapter 4 of this thesis found that increasing slope heterogeneity in association with increased habitat diversity buffered butterflies against widespread declines associated with ECEs. Finally, chapter 5 of this thesis found that butterfly families respond differently when accounting for all extremes across all life stages, but that life history traits such as dispersal and number of larval host plants can be used to predict a species sensitivity to various ECEs.

Policies related to the reduction of both carbon dioxide emissions and energy consumption within the residential sector have contributed towards a growing number of passive houses and other highly energy-efficient dwellings being built in many countries. Since these dwellings are very well insulated and airtight, concerns have been raised over the quality of the indoor air and, consequently, the possible health effects for their occupants. Additionally, following well established evidence from the residential energy consumption literature, it has been considered vital to explore occupants’ practices when trying to understand possible contributions to the quality of the indoor environment in passive houses, and thus any potential effects to the health of occupants. Nevertheless, very little research has explored this issue. This longitudinal, mixed methods, interdisciplinary study has collected and analysed qualitative data (from house occupants’ interviews and diary) and quantitative data (from the monitoring of the indoor climate and indoor air quality) over three different seasons (winter, spring and summer) from different rooms in five passive houses and in four conventional (control) houses in the UK. Additionally, data has been compared with reviews of epidemiological, toxicological and other health related published studies to reveal the following: Passive houses can provide either a potentially healthy or unhealthy environment for their occupants, depending on the hazard being analysed. For instance, when analysing indoor temperatures, passive houses were found to be potentially healthy during cold months but potentially unhealthy during the summer. On the other hand, the analysis of relative humidity levels suggest that passive houses are potentially healthy during the summer and potentially unhealthy during the winter. Potential health risks in passive houses were caused by one or a combination of variables, including passive house design and construction and occupants’ practices.

The human M3 muscarinic acetylcholine receptor (M3R) regulates many important physiological roles in the central and peripheral nervous systems, and it is involved in the pathophysiology of several neurodegenerative and autoimmune diseases, representing attractive potential pharmacological target for intervention. However, the lack of structural information on this receptor hampered the development of new potent antagonist with increased selectivity and lower side effects. Such structural information can be only achieved by means of experimental biophysical techniques, which require large quantities of pure receptor. Considering that under physiological conditions the expression of G-protein coupled receptors (GPCRs) is relatively low, optimization of the receptor overexpression is a pre-requisite for structural studies efforts to be performed. In addition, although is has well established that GPCR undergo post-translational and increase evidences support that these are tight links to receptor roles, little progress has been made in the post-translational modifications field in some GPCRs, such as the case of M3R. In this study, we provide some strategies to improve muscarinic receptor heterologous expression in mammalian cells guaranteeing proper post-translational modifications. In addition, we have been able to extract high levels of functional receptor from COS-7 cells using a detergent combination tested, and to purify the receptor to near homogeneity-keeping the full wild type receptor properties- by means of different affinity purification methods. Regarding the post-translational modifications studied, our findings provide the first evidence of the critical role that N-glycan chains play in determining muscarinic receptor distribution and localization, as well as in cell integrity. Furthermore, our data reveal a role for palmitoylation in determining M3R residence within lipid raft, as well as in receptor internalization and down-regulation / El receptor muscarínico de acetilcolina subtipo M3 humano (M3R) regula importantes funciones en el sistema nervioso central y periférico, y está implicado en la fisiopatología de varias enfermedades neurodegenerativas y autoinmunes, lo que representa una atractiva diana terapéutica para la intervención farmacológica. Sin embargo, la falta de la información estructural sobre este receptor obstaculizado el desarrollo de nuevos y potente fármacos de gran selectividad y bajo efecto secundario. Tal información estructural, puede lograrse por medio de la experimentación con técnicas biofísicas que requieren grandes cantidades de receptor puro. Teniendo en cuenta que en condiciones fisiológicas la expresión de receptores acoplados a proteínas G (GPCR) es baja, la sobreproducción del receptor es un pre-requisito para que los estudios estructurales puedan ser realizados. Además, aunque se ha establecido que los GPCR sufren modificaciones post-translationales y que en los últimos años un significante número de reportes sugieren que estas modificaciones están estrechamente vinculadas a las funciones del receptor, poco se ha avanzado en el estudio de estas modificaciones en el campo de algunos GPCRs, como es el caso de M3R. En este estudio, nosotros describimos algunas estrategias para mejorar la expresión de los receptores muscarínicos en células de mamíferos garantizando unas correctas modificaciones post-translacionales. Además, hemos sido capaces de extraer altos niveles de receptor funcional a partir de células COS-7 con una combinación de detergentes, purificamos el receptor M3R cerca de la homogeneidad, mantenimiento de la totalidad de las propiedades biológicas encontradas en el receptor silvestre. En relación a las modificaciones post-translationales estudiadas, nuestros resultados proporcionan la primera evidencia del papel crítico de las cadenas de N-glicanos en la determinación de la localización de estos receptores, así como en la integridad celular. Además, nuestros datos revelan un importante papel de las modificaciones lipídicas de M3R en relación a la distribución del receptor en microdominios resistente a detergentes, así como en la regulación del receptor. En resumen, las estrategias utilizadas pueden contribuir al incremento de la expresión M3R. De esta forma los esfuerzos para la purificación del receptor a gran escala pueden ser iniciados. Para ellos, nosotros revelamos una posible estrategia. Además, proponemos los posibles sitios de N-glicosilación y S-acilación en el M3R expresado en células COS-7, y proporcionamos evidencias experimentales que avalan la implicación funcional de estas modificaciones en el papel del receptor.

The aim ofthis research was to develop cheap and readily available charcoals as a remediation tool for contaminated land and water. Whereas (activated) charcoal is well known for its toxic adsorbing properties, relatively little is known about how the choice of source material affects the sorption properties of the resulting charcoal and why. In the first instance, research focused on metal sorption properties of a range of charcoals produced from contrasting wood types that are commonly grown for commercial purposes (Scotch Pine, Sweet Chestnut and Poplar). It could be shown that the metal sorption properties of these charcoals were proportional to their internal surface area and that the nanostructure of activated charcoal did not contribute to metal sorption. Subsequently charcoals made from a range ofnon-woody plants were assessed for their metal sorption capacity. It was found that plant growth rate was related to metal sorption capacity. Fast growing plants such as Stinging Nettle and Swiss Chard produce charcoals with metal sorption capacities in excess of200 000 mg Cu kg-\. The mechanisms of metal sorption by these charcoals were demonstrated to be through ion exchange and surface precipitation. It was demonstrated that source materials high in Na, K, Mg and Ca or with high ash contents, produced highly metal sorbent charcoals.

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