Overcoming fragmentation and isolation requires innovative solutions if cohesive biodiversity networks are to be created in modernised landscapes. Within Europe much of the biodiversity interest is in semi-natural habitats that exist as isolated reserves. This thesis aimed to test the connectivity potential of open habitat for lowland heathland biodiversity within a mosaic forest landscape. A range of experimental management treatments were implemented covering a gradient of disturbance intensity intended to enhance connectivity through plantation forest for early-successional biodiversity. Both species composition and life history traits were investigated enabling a comprehensive interpretation of response across multiple species. Sampling programs identified over 87000 invertebrates, comprising 38188 spiders from 183 species, 41531 ants from 20 species and 7564 carabids from 93 species, and recorded 23241 observations of 222 vascular plant species. Initial investigations revealed forestry trackways contained a component of the regional heathland spider assemblage, but this was significantly degraded as adjacent forest matured. Experiments to augment heathland biodiversity in trackways resulted in contrasting responses between taxa. Specialist carabids and vascular plants (associated with heathland or early-successional habitats), increased in abundance and richness with high intensity disturbance. Spider assemblages were left depauperate and did not completely recover after two seasons; ants did not respond at any disturbance level. Trait-based analysis showed that the abundance of aerial dispersers increased and size decreased with disturbance intensity for carabids and plants. In contrast, spider body size increased with greater disturbance and aerial dispersal was not significant. For spiders, ephemeral stepping stones, in the form young restock coupes, support the majority of the heath assemblage, whereas open linear habitat in the form of trackways, suffer from edge effects and are dominated by generalist and woodland spiders. Network cohesion will benefit from intensive disturbance management and a combination of connectivity elements to incorporate contrasting dispersal abilities.

North Sea demersal fishes and fisheries have changed over the past 100 years. To detect the main factors driving these changes, long-term data are needed. Using historical fisheries data that extend throughout the 20th century, this thesis aims to assess drivers influencing developments in fisheries as well as changes in the distribution and abundance of commercially important fishes in the North Sea. For English demersal fisheries, favourable political, technological and economical drivers were identified, inducing a vast rise in English fisheries in the first half of the 20th century; however, the same drivers, acting adversely, influenced the decline in recent decades and the emphasis of fisheries shifted from England to Scotland. Different trends in distribution were observed for North Sea whiting, turbot and brill between the 1920s and 2000s. Whiting distribution shifted westward between the late 1940s and1960s, whereas turbot nearly disappeared from the northern North Sea from the 1970s onwards. Brill distribution remained rather stable in the central and southern North Sea. The reasons for the longitudinal shift of whiting remained unclear as the relationships to two potential drivers, climate change and fishing pressure, were not strong. For turbot, the cause for the near disappearance from the northern North Sea is inconclusive. Commercial fisheries data were assessed reliable for distribution analysis when comparing commercial data of whiting, a commonly discarded species, and unbiased survey data. Whiting, compared to flatfish, is of secondary commercial importance. In areas where discrepancies occurred between commercial and survey data, higher discarding of whiting is suggested, as highly priced flatfish are caught there. This thesis demonstrates past conditions of demersal fish populations and fisheries in the North Sea and presents the effects of different drivers on them. The documented changes in fishes and fisheries contain valuable information for resetting baselines and developing appropriate management strategies.

Hypoxia and anoxia alter the behaviour, diversity and habitat of the benthic communities and cause accumulation of organic matter and nutrients. Most studies have focused on the effect of anoxia on benthic organisms and little information is available on nutrient sediment-water fluxes and rates of key biogeochemical processes. This study aimed to evaluate the oxygen concentration at which harmful effects start to occur, the rates that the system responds to different levels of oxygen saturation in the overlying water and the recovery times of system processes when re-aeration are restored. Sampling was carried out at Breydon Water, Great Yarmouth in June, 2010 and key biogeochemical processes were monitored in sediment/artificial seawater mesocosms maintained at constant temperature in the laboratory. The experimental work assessed the short term effect of different levels of oxygen by manipulating oxygen into five different treatments; oxic (96% saturation in the overlying water), hypoxia (25% saturation), one day of anoxia (24 hours without oxygen followed by re-aeration of up to 6 days), four days of anoxia (4 days without oxygen and subsequent re-aeration for 3 days) and seven days of anoxia (0% saturation). The effect of these oxygen concentrations on different biogeochemical processes (solute transport, oxygen uptake, nutrient fluxes, porewater chemistry, and enzyme activities) was quantified. Bromide used in solute transport assessments were analysed using inductively coupled plasma mass spectrometry and oxygen was measured using an oxygen minielectrode. Nutrient analysis was carried out using the SKALAR autoanalyser and enzyme activities were measured using microplate based assays. With decreasing oxygen supply, ammonium and phosphate are rapidly released into the water column, and nitrate concentrations decrease, reflecting the reducing conditions. In oxic conditions, rapid transport of water and oxygen into the sediments occurs through irrigation fluxes. Slower transport was observed from the porewater of anoxic treatments, as only molecular diffusion occurs. Vertical profiles of alkaline phosphatase, cellobiohydrolase, β-glucosidase and chitinase activities in the sediment reflect organic matter inputs decreasing with depth. Urease activity was enhanced following anoxic incubations of 7 days, with an inverse relationship with porewater ammonium concentrations and increased total organic carbon input. The biogeochemical resilience of the system is dependent on the duration of anoxic events. The effect of 1 day anoxia is relatively reversible and the system recovers to normal conditions within the 7 days of treatment. However, hypoxia (25% oxygen saturation) or longer duration (4 days) anoxia followed by re-aeration are enough to cause negative effects on the biogeochemical functioning of the system. So, sediment biogeochemistry has some resilience towards short term anoxic events, but more prolonged hypoxia or anoxic events that are continued for only a few days can have major effects on ecosystem function.

This thesis investigates biofuel expansion as a disturbance to the resilience of social-ecological systems. Examining this issue through a resilience framework illustrates the dynamics of such systems, identifying potential trade-offs and regime shifts. Additionally, this research highlights the differentiated impacts for actors across multiple scales, allowing power relations to be taken into account – the lack of which is a common criticism of resilience studies. The thesis presents a systems analysis of sugarcane-ethanol expansion in Ethiopia at the current and planned levels of production, incorporating both the production and consumption sub-systems. To create an integrated systems analysis multiple methods were utilised between 2010 and 2012 to collect primary data – household surveys and interviews in multiple localities and interviews with key stakeholders, supplemented with documentary evidence. The production sub-system analysis incorporates food system impacts at the household scale and ecological impacts at the regional scale, whilst the consumption sub-system analysis investigates the impacts of ethanol adoption as a household fuel. The findings of these analyses are then synthesised in a resilience assessment at the national scale. The results show that current levels of sugarcane and ethanol production have not surpassed the majority of potential critical thresholds that would induce regime shifts. Therefore, most of the sub-systems under study, and actors within them, are resilient to the perturbation of biofuel expansion to date. However, a detrimental regime shift is underway for pastoralists being relocated for sugarcane expansion. The planned expansion will replicate this regime shift across a much larger population. In addition, the larger scale of operation will more severely influence the ecological sub-system. The analysis of multiple nested scales using a resilience model demonstrates the need to examine all scales to highlight the winners and losers, as only examining one scale conceals the dynamic nature of interactions.

Concerns about climate change have rejuvenated global efforts in reducing carbon dioxide (CO2) emissions. Tactics include capture and sequestration of CO2 from point sources and the promotion of hydrogen (H2) as a “transport fuel”. Current H2 vehicles use high pressure H2 tanks which lack the convenience of their fossil fuel counterparts and present potential safety hazards. Development of adsorbent materials that reduce the energetic costs of H2 and CO2 capture, facilitating reversible storage under safer conditions, are hoped to increase the viability of these technologies for industrial application. This thesis is the first to utilise magnetron sputtering, a technique allowing fine control over nano-material synthesis, for the design of novel solid adsorbents and deposition of novel dopants for H2 storage and CO2 capture. Work includes an in-depth study of the influence of nitrogen as a sputter gas on the growth of carbonaceous films, and is the first to explore these films performance as H2 and CO2 adsorbents. Several conflicting nitrogen effects were identified, their influence on the films growth dependent upon the nitrogen fraction of the sputter gas. Performance of the deposited films as adsorbents was also dependent on the growth conditions. The H2 storage capacity at 77 K and 20 bar of an optimised adsorbent, synthesised by magnetron sputtering, was 4.7 wt.%, comparable in performance to alternatives from the literature. Further work provides the first evidence that cerium, deposited by magnetron sputtering, can function as an adsorbent catalyst and identified that sputtering is a worthwhile, yet slow process for adsorbent doping as it facilitates intimate binding between the adsorbent and the dopant. The novel synthesis of graphene by magnetron sputtering was also attempted. Whilst tests failed, results collected could provide guidance for more successful attempts in the future.

Climate change is affecting UK agriculture, and research is needed to prepare crops for the future. Wheat is the UK’s most important crop, and needs to be protected from losses caused by disease. While direct effect of the environment on pathogen spread is often reported, effect of the environment on host defence is not. Many wheat resistance genes are temperature sensitive and these were used as a starting point to investigate defence temperature sensitivity in wheat starting with yellow rust resistance gene Yr36, previously shown to be temperature-sensitive. The effect of temperature on resistance was shown to be independent of Yr36 in breeding line UC1041, and was more likely to be due to a previously-uncharacterised background temperature sensitivity. These results suggest that temperature changes, rather than thresholds, might influence some disease resistance mechanisms. Understanding this phenomenon could enable the breeding of more stable defence in crops. In order to gain further insight into how temperature changes influence resistance, plants were grown under different thermoperiods and challenged with different types of pathogens; Results showed that resistance to multiple pathogens in one cultivar Claire was enhanced under variable temperatures, compared to constant temperatures. Taken together, the research presented revealed that defence temperature sensitivity in plants is much more complex than previously thought, considering that both temperature changes and different thermoperiods can influence aspects of wheat defence. To ascertain which research approaches will be most valuable in preparing for climate change, the effect of the environment on take-all was also investigated. Vulnerable periods for wheat from the threat of take-all development were identified by analysing historical datasets, and controlled environment experiments. Results showed a relationship between initial post-sowing temperatures and spring take-all levels in 2nd 3rd or 4th winter wheats, depending on the location. The work on yellow rust resistance and take-all both identify vulnerable periods for wheat caused by the environment, be it weakening of host defence responses, or increased threat from disease pressure. Further characterisation and understanding of vulnerable periods will be essential to control disease outbreaks under an increasingly unstable climate.

There is an urgent need to reduce domestic energy consumption, particularly due to climate change. Domestic energy policies and research have been dominated by the assumption that technological provision will linearly save energy. Conventional attempts to move away from this approach have not gone far enough, tending to still assume that technological usage is a linear outcome of an individual’s rational decision-making. This thesis takes a significantly different approach by drawing on social practice theory and focusing on how everyday life is performed. Specifically, a Passivhaus housing development is adopted as a case study in investigating the everyday consequences of advancing dwelling design. Passivhaus is a German energy efficiency building standard, employing very different technologies relative to conventional UK housing. Specific attention is given to how unfamiliar technologies influence domestic practices more generally, as well as appliance-using practices and designing and constructing practices more specifically. This thesis has significant empirical, methodological and theoretical contributions. Empirically, everyday examples illustrate the unintended consequences of new technologies, providing insight on how such technologies could change practices in the future. Methodologically, by treating quantitative consumption-related data (e.g. building monitoring, appliance ownership, construction data) as by-products of performing practices, an innovative mixed methods approach provides unique insights on everyday practices. Theoretically, the potential usefulness of a practices approach is emphasised; in particular, in developing a detailed and contextual understanding of how everyday life is constructed and how it is open to change (often in unexpected ways). This thesis reiterates that research and policy should focus on practices, rather than technological performance or what individuals think about technologies. It concludes by: discussing a re-framing of policy expectations; outlining how energy saving interventions could target domestic practices and its influencing elements; and providing a series of new research ideas that have been generated by this thesis.

Plant-microbe interactions in the rhizosphere, the region of soil influenced by plant roots, are integral to biogeochemical cycling, and maintenance of plant health and productivity. Interactions between model plants and microbes are well understood, but relatively little is about the plant microbiome. Here, comparative metatranscriptomics was used to determine taxonomic compositions and metabolic responses of microbes in soil and the rhizospheres of wheat, oat and pea. Additionally a wild-type oat was compared to a mutant (sad1) deficient in production of antifungal avenacins. Analyses of taxonomic compositions and functions based on rRNA and protein coding genes agreed that rhizosphere microbiomes differed from soil and between plant species. Pea had a stronger effect than wheat and oat, suggesting distinct cereal and legume microbiomes. Proportions of eukaryotic rRNA in the oat and pea rhizospheres were more than fivefold higher than in the wheat rhizosphere or soil. Nematodes and bacterivorous protozoa were enriched in all rhizospheres, while the pea rhizosphere was highly enriched for fungi. Only the eukaryotic community was distinct from wild-type oat in the sad1 mutant, suggesting avenacins have a broader role than protecting from fungal pathogens. The addition of an internal RNA standard allowed quantitative determination of global transcriptional activity in each environment. This was generally higher in the rhizospheres, particularly pea, than in soil. Taxa known to possess metabolic traits potentially important for rhizosphere colonisation, plant growth promotion and pathogenesis were selected by plants. Such traits included cellulose and other plant polymer degradation, nitrogen fixation, hydrogen oxidation, methylotrophy and antibiotic production. These functions were also more highly expressed in rhizospheres than soil. Microbes also induced functions involved in chemotaxis, motility, attachment, pathogenesis, responses to oxidative stress, cycling of nitrogen and sulphur, acquisition of phosphorous, iron and other metals, as well as metabolism of a variety of sugars, aromatics, organic and amino acids, many plant species specific. Profiling microbial communities with metatranscriptomics allowed comparison of relative and quantitative abundance of microbes and their metabolism, from multiple samples, across all domains of life, without PCR bias. This revealed profound differences in the taxonomic composition and metabolic functions of rhizosphere microbiomes between crop plants and soil.

Andesite lavas from the current eruption of the Soufrière Hills Volcano, Montserrat exhibit evidence for magma mingling, related to the intrusion of mafic magma at depth. The processes of mass transfer and flux of material involved in the interaction between mafic and silicic magmas are crucial for understanding eruption dynamics. Detailed textural, petrological and geochemical analyses coupled with field observations are used to define a classification scheme for mafic enclave types in erupted andesite from phase V (2009–2010). Type A are closest to a mafic end-member, whereas type B are significantly hybridised. Type A quench crystallisation is driven by rapid thermal equilibration during injection into the andesite. Type B enclaves form from a slower cooling vesiculating hybridised melt layer. Type C, are a composite of types A and types B, representing an interface between the types. Geochemical modelling shows that since the start of the current eruption that the dominant control on the range of enclave bulk compositions has changed from fractional crystallisation to mixing of the mafic end-member and host andesite. A change in selected elements concentrations in the mafic end-member is observed from phases I to III, halting in phase V. Volatile flux from the mafic to andesite magmas plays a vital role in eruption dynamics, but evidence for vapour transport in the erupted lavas is rarely preserved. Geochemical and petrological evidence is presented for the segregation and transport of metal-bearing vapour in shear fractures generated in the shallow conduit or dome during magma ascent. Elevated metal concentrations (Cu, Au, Ag, Pb, Zn) indicate magmatic vapours transport. Volatiles were resorbed into the partial melt generated during frictional heating (>1000 °C) at the slip surface as a peraluminous partial melt recrystallised. The shear zones provide evidence for degassing and an insight into controls on eruption style.

No description available.