• Canada
• 2012-2021close
• UK Research and Innovation close
• 2015 close
• 2017 close

Variations in sea level have a great environmental impact. They modulate coastal deposition, erosion and morphology, regulate heat and salt fluxes in estuaries, bays and ground waters, and control the dynamics of coastal ecosystems. Sea level variability has importance for coastal navigation, the building of coastal infrastructure, and the management of waste. The challenges of measuring, understanding and predicting sea level variations take particular relevance within the backdrop of global sea level rise, which might lead to the displacement of hundreds of millions of people by the end of this century. Sea level measurement relies primarily on the use of coastal tide gauges and satellite altimetry. Tide gauges provide sea levels at fine time resolutions (up to one second), but collect data only in coastal areas, and are irregularly distributed, with large gaps in the southern hemisphere and at high latitudes. Satellite altimetry, in contrast, has poor time resolution (ten days or longer), but provides near global coverage at moderate spatial resolutions (10-to-100 kilometres). Altimetric sea level products are problematic near the coast for reasons such as uncertainties in applying sea state bias corrections, errors in coastal tidal models, and large geoid gradients. The complicated shoreline geometry means that the raw altimeter data have to either undergo special transformations to provide more reliable measurements of sea level or be rejected. Developments in GPS measurements from buoys are now making it possible to determine sea surface heights with accuracy comparable to that of altimetry. In combination with coastal tide gauges, GPS buoys could be used as the nodes of a global sea level monitoring network extending beyond the coast. However, GPS buoys have several downsides. They are difficult and expensive to deploy, maintain, and recover, and, like conventional tide gauges, provide time series only at individual points in the ocean. This proposal focuses on the development of a unique system that overcomes these shortcomings. We propose a technology-led project to integrate Global Navigation Satellite Systems (GNSS i.e. encompassing GPS, GLONASS and, possibly, Galileo) technology with a state-of-the-art, unmanned surface vehicle: a Wave Glider. The glider farms the ocean wave field for propulsion, uses solar power to run on board equipment, and uses satellite communications for remote navigation and data transmission. A Wave Glider equipped with a high-accuracy GNSS receiver and data logger is effectively a fully autonomous, mobile, floating tide gauge. Missions and routes can be preprogrammed as well as changed remotely. Because the glider can be launched and retrieved from land or from a small boat, the costs associated with deployment, maintenance and recovery of the GNSS Wave Glider are comparatively small. GNSS Wave Glider technology promises a level of versatility well beyond that of existing ways of measuring sea levels. Potential applications of a GNSS Wave Glider include: 1) measurement of mean sea level and monitoring of sea level variations worldwide, 2) linking of offshore and onshore vertical datums, 3) calibration of satellite altimetry, notably in support of current efforts to reinterpret existing altimetric data near the coast, but also in remote and difficult to access areas, 4) determination of regional geoid variations, 5) ocean model improvement. The main thrust of this project is to integrate a state-of-the-art, geodetic-grade GNSS receiver and logging system with a Wave Glider recently acquired by NOC to create a mobile and autonomous GNSS-based tide gauge. By the end of the project, a demonstrator GNSS Wave Glider will be available for use by NOC and the UK marine community. The system performance will be validated against tide gauge data. Further tests will involve the use of the GNSS Wave Glider to calibrate sea surface heights and significant wave heights from Cryosat-2.

Controversy surrounds the actual impacts of Atlantic salmon farming on wild salmonid stocks, fed by the lack of direct evidence for or against many potential impacts, with uncertainty an increasing impediment to sustainable industry development and effective management of wild stocks. This applies to the potential impact of the introgression of farm genomes into locally adapted wild populations from breeding of farm escapes. Escapes do occur and are recognized as inevitable, but are a very small fraction of farm stocks and vary in numbers both locally and temporally. The majority of escapees are expected to die without breeding but some do remain in or ascend rivers and spawn. However, a detailed understanding of actual levels of interbreeding and introgression in most rivers is lacking which, along with an understanding of the adaptive differentiation of farm and wild salmon, is required to establish the actual impact of this potential interaction on the productivity and viability of wild populations. Detection and quantification of interbreeding and introgression requires diagnostic markers for farm and wild genomes. Genetic differentiation of farm and wild genomes can evolve through founder effects, selective breeding and domestication selection and is observed in respect of a variety of molecular markers. However, existing molecular markers are not fully diagnostic and regionally constrained in their usefulness. Unfortunately, marker panels screened for useful variation have been small and arbitrary such that they are unlikely to include the most informative loci and to be context specific, limiting their power and transferability. To properly address the issue of introgression molecular markers are required that are highly diagnostic across all farm and wild populations. These markers will be in genomic regions involved in domestication and controlling the expression of selected economic traits. What is known of the genomic architecture of domestication and most economic traits indicates their control is polygenic, making the targeting of specific gene regions in the search for markers difficult. In contrast, recent advances in genomics make possible genome scanning and genome-wide association studies (GWAS) which can provide a high resolution assessment of molecular differentiation between different individuals or populations across the genome. Different GWAS strategies can be employed but two are deemed optimal in the current context. Firstly, a GWAS will be carried out using a new Atlantic salmon SNP (single nucleotide polymorphism) containing 930k nuclear SNPs, recently developed in collaboration with the salmon farming industry. This will be carried out on a broad base of representative farm and wild stocks. Secondly, GWAS will be carried out to identify temporally stable epigenetic DNA-methylation base changes induced by rearing fish in culture by comparing groups of single source wild fish reared in the wild and in culture. The study will deliver the first general understanding of domestication related molecular genetic differentiation between farmed and wild salmon and identify the best markers for identifying farm salmon in the wild and assessing genetic introgression of farm genes into wild populations. The work will deliver a more robust and generally applicable tool for determining the actual levels of escapes and introgression in wild salmon populations. Following field calibration and independent validation, the diagnostic methodology defined in the study is expected to provide the basis for generating the evidence needed to clarify the debate on levels of escapes and introgression and the long term impacts of introgression on population viability. This will help to define more clearly the path forward for the sustainable development of the salmon farming industry in the UK and elsewhere in the North Atlantic region and help to inform management priorities for wild Atlantic salmon stocks.

The proposed research contributes to fundamental topics in Combinatorial Optimisation, aiming to devise strongly polynomial algorithms for new classes of linear and nonlinear optimisation problems. The notion of polynomial-time complexity, introduced in the 1970s, is a standard way to capture computational efficiency of a wide variety of algorithms. Strongly polynomial-time algorithms give a natural strengthening of this notion: the number of arithmetic operations should not depend on numerical parameters such as costs or capacities in the problem description, but only on the number of such parameters. Strongly polynomial algorithms are known for many important optimisation problems. However, it remains an outstanding open problem to devise such an algorithm for a very fundamental optimisation problem: Linear Programming. The most important goal of the proposal is to develop a strongly polynomial algorithm for linear programs with at most two nonzero entries per column. The problem is equivalent to minimum-cost generalised flows, a classical model in the theory of network flows. Finding a strongly polynomial algorithm was a longstanding open question even for the special case of flow maximisation, resolved by the applicant in a recent paper. Further goals of the proposal include strongly polynomial algorithms for related nonlinear optimisation problems. Nonlinear convex network flow models have important applications for market equilibrium computation in mathematical economics. Very few nonlinear problems are known to admit strongly polynomial algorithms. The proposal aims for a systematic study of such problems, and will also contribute to the understanding of computational aspects of market equilibrium models.

Parasitism is a widespread phenomenon in the natural world, with dramatic consequences for hosts, parasites, and their communities. There are over 3,000 described parasitic plant species, including mistletoes, the important grassland plant Rhinanthus, and the agricultural pest Striga. A particularly interesting, yet poorly studied group, are the facultative hemiparasites-which can grow and reproduce independent of a host, but grow more vigorously after host attachment. Facultative hemiparasitism represents a remarkably flexible growing strategy, which has largely been overlooked in preference of studies of obligate parasites-organisms which require a host to complete their lifecycle. This project investigates a case study of facultative hemiparasitism, from an evolutionary genetic perspective. The genus Euphrasia contains approximately 300 species, all of which are facultative hemiparasites. This proposal will make progress towards using this genus as a study system for investigating the evolutionary consequences of facultative hemiparasitism, on two fronts. Firstly, it will provide the funds to test emerging genomic approaches, develop new protocols, and produce preliminary data, required for ongoing research in Euphrasia. This will include testing a new chloroplast genome enrichment approach, applying a tissue-specific RNA sequencing method, and the development of a draft whole genome sequence. These resources will be essential for future work identifying loci involved in the evolution of facultative hemiparasites, and testing whether plant parasites are a vector for adaptive horizontal gene transfer. Secondly, this proposal will develop an international collaboration between a UK researcher in plant evolutionary genomics, the world expert in plant parasitism, a leader in plant genomics, and an international expert in the biology of Euphrasia. Such an international collaboration draws on the long history of research of parasitic plants in the USA, as well as the knowledge of Euphrasia biology centred in mainland Europe, to tackle questions about hemiparasitism in an integrated fashion. An increased understanding of plant parasitism will greatly benefit many areas of research, including evolutionary biology, plant biology, parasitology, and genome biology. In particular, understanding genomic changes associated with parasitism will be informative for researchers interested in the genetic basis of major life history transitions, while an understanding of transcriptional changes during host attachment will demonstrate a dramatic example of gene expression changes in the life of an organism. More generally, the identification of common loci underlying parasitic growth across diverse plant parasites, will facilitate the development of genetic tools to tackle parasitic plants that grow as agricultural pests.