Given that SARS-CoV-2 RNA is detectable in faeces for prolonged periods (even for otherwise asymptomatic individuals), efforts have so far concentrated on trying to map its prevalence using sewage samples, e.g. via our partners at Bangor University (NERC Urgency Grant NE/V004883/1). Because live viruses have also been detected in the stools of patients affected by COVID19, there is growing concern about the risks of faecal-oral transmission to humans and/or wildlife (where the virus first originated) via sewage outflows and overspill. This is particularly worrying as, for example, hundreds of tonnes of raw sewage enter the Thames each year when sewers overflow during rainstorms, effectively bypassing sewage treatment works (STWs) when they exceed capacity. We combine expertise from Life Sciences and Mathematics at Imperial College, corona virology at Nottingham University, and a network of collaborators to fill this gap and to complement ongoing work in related (but not overlapping) areas. We have also already secured £49K of internal funding from Imperial College to prime the lab work, as a direct in-kind contribution. First, the potential for sewage (via effluent discharge, storm overflows, and other forms of run-off) to contribute to transmission to humans and wildlife will be measured by assessing RNA concentration and viral infectivity from environmental samples, from sewage outflows down to rivers, estuaries, and faeces from wildlife. Second, using data on concentrations of SARS-CoV-2 RNA in sewage and in the environment, we will provide models of population-level prevalence of COVID19 and elucidate key environmental transmission routes for management.

Freshwater ecosystems provide critical ecosystem services that underpin human societies and wellbeing: including water purification, carbon capture, and the maintenance of sustainable fisheries. However, these ecosystems are under an increasing array of threats, both in the UK and worldwide, especially from a wide range of new and emerging chemical stressors (e.g. novel antibiotics and pesticides). Freshwater biosciences and applied ecology are under-equipped for dealing with these new threats: the evidence base is lacking, there is often little or no mechanistic understanding, or predictive capacity for anticipating how these novel chemicals will operate in the real world. This is particularly true for the ecosystems of the future that are being reshaped and constructed by climate and other environmental changes. Our project will address all these shortcomings by taken a radically different approach from the classical biomonitoring and ecotoxicology tools that have dominated for many decades. We aim to unearth the general rules by which emerging chemical stressors operate through, and alter, networks of interacting species - from microbes at the base of the food web, through to apex predators in the fish community at the top. This will involve the development of indicators of both proximate pollution, as the chemical first enters the biological system (commonly as a new food source for microbes), and also of its indirect effects as its impact propagates through the food web. For instance, we will be able to answer questions such as: if a new insecticide wipes out the invertebrates in the middle of the food web, does this trigger blooms of nuisance algae as they are no longer kept in check? To achieve this, we will develop a new suite of methods at the ecosystem level that combine lab and field experiments to detect the causal mechanisms that we currently do not understand. The experiments will be combined with mathematical modelling to predict ecosystem-level impacts. We will address both, contemporary ecosystems that could be under imminent threat from new chemical stressors, and ecosystems of the future that will emerge under different scenarios of land-use and climate change. This will provide a completely new paradigm in chemical stressor monitoring, based on using first principles to derive a novel means of predicting "ecological surprises" that commonly arise due to the inadequacies of our current simplistic approaches when dealing with the true biocomplexity of natural systems. Our scope is for our approach to serve as a diagnostic tool for management, with research findings, for example, supporting the selection of mitigation options that deliver reduction of ecological effects. This paradigm shift will allow far more robust predictions and therefore more informed management decisions about the freshwaters of the future. The work will bring together the field of pure and applied ecological science, to the mutual benefit of both sets of disciplines. Our proposal represents the first steps along this path to the more multidisciplinary perspective that is going to be critical for dealing with future threats to our ecosystems - from emerging chemical stressors in freshwaters to the growing list of other environmental threats looming on the horizon. Because the approach is general, it will not only pave the way for the next generation of ecological assessment in freshwaters, but it can also be adapted for applications in marine and terrestrial ecosystems.

The summer of 2022 has seen the highest air temperatures ever recorded in England and the lowest July rainfall since 1935. This drought, the worst in Europe for 500 years, has resulted in the widespread drying of river channels over large parts of England and Wales. Whilst extreme in historic terms, the drought provides a foretaste of the conditions expected with climate change: such extreme hydroclimatic events are expected to become more frequent in the future. Our ability to predict the impact of such droughts on the biological communities living in rivers, and hence mitigate the most severe effects, is constrained by a limited understanding of the factors influencing their abilities to resist the effects of drought and to recovery once flow resumes. Here the substrate of the river bed is particularly important, as many animals will retreat into wet subsurface substrate once surface water has been lost. Without a clear understanding of how substrate characteristics affect the response of rivers to drought, river managers cannot prioritize the most vulnerable rivers for protection from drying. We are in a unique position of having an experiment already set up in multiple replicated stream channels that will enable us to experimentally examine the effects of substrate/fine sediment on the response of river communities to drought and on their potential to recolonise and recover following the resumption of flow. The experiment, set up to look at the effects of substrate composition and fine sediment loading on the macroinvertebrate communities dried naturally as water levels declined during the drought, with the treatments left in situ. We will explore how substrate characteristics influence i) the ability of invertebrates to persist through drought in the river bed, ii) the ability of invertebrates to recolonise the river by emerging from the river bed once flow resumes, and iii) the relative importance of recolonisation from the river bed compared with other routes of colonization (aerial or drifting).

The recent surge in popularity of wild swimming (also referred to as open water swimming or cold water swimming), or swimming in natural 'blue spaces', including rivers, lakes or the sea, has highlighted the significant scale of opportunity to leverage the use of blue spaces as community assets to combat health inequalities. However, despite the well documented physical and mental health benefits of wild swimming that are relevant to large groups of the population suffering from ill health, current prevention and intervention strategies that focus on wild swimming to mitigate health inequalities tend to be local, place-based and disparate, and lack an overall joined-up approach that would allow them to be scaled up to benefit whole communities as part of established health policy. In collaboration with our project partners (Swim England, Black Swimming Association, The National Trust, Freshwater Biological Association, UK Centre for Hydrology and Ecology, Leicestershire County Council, Social Prescribing at Partners Health, and Thrive health content developers), we have identified one of the main barriers to scaling up successful place-based approaches: the current lack of integrated information about the mental and physical health benefits of wild swimming alongside the risks related to water quality and safety aspects of specific blue spaces that people use for swimming. Our project brings together a team of leading arts and humanities researchers in applied linguistics (Adolphs, Knight, Sotirova), place-based literatures (Jackson, Pratt), and place-names (Carroll), alongside leading experts in health sciences and organisation level implementation strategies (Moffatt and Timmons), and an internationally renowned expert on water quality and freshwater ecosystems (McGowan). Together with our project partners, we bring to bear our combined interdisciplinary expertise to address the following two main research questions: RQ1: How can we co-create an evidence base and sample content about wild swimming that will facilitate scale up of local approaches and initiatives to combat health inequalities? Drawing on databases and sources relating to the histories, literatures, health benefits and safety aspects, as well as water quality of blue spaces, we will co-create and evaluate sample content with our partners and with input from current and prospective swimming communities. RQ 2: What kind of mechanisms and relationships need to be formed and formalised to scale up approaches that leverage blue spaces to combat health inequalities through wild swimming? Working closely with our project partners, we will map the implementation landscape and provide a route map for wider scale up and spread of wild swimming as a health and wellbeing intervention, delineating the full range of agencies that may be involved in this process. Our project will have significant benefits for users within and beyond the academic community. We will develop a new mixed methods approach, drawing on corpus linguistics and narrative analysis, to create effective public health messaging that includes content from a range of academic disciplines. This content, in turn, will be of benefit to promoters and commissioners of wild swimming in the health ecosystem, allowing for scale up of local initiatives. Ultimately our project will benefit the many individuals and diverse communities who will be enabled to enjoy wild swimming in a safe way to improve health, and to gain an increased awareness of the nature of blue spaces and their role as a community asset.

Lake ecosystems face multiple stresses including nutrient enrichment, climate change and invasion of nonindigenous species. This latter stress is widely recognised as having a major impact on biodiversity and the functioning of ecosystems worldwide and its effects are increasing because human activity has enhanced rates of dispersal and climate change is opening new niches at high latitudes. Windermere, comprising two basins, is England's largest lake and one of the best studied in the world with detailed records extending back for up to 70 years. A marked deterioration in water quality has been observed in the last 10 to 15 years despite continued removal of a key nutrient, phosphorus, at the wastewater treatment works. For example, summer algal blooms have increased and concentrations of oxygen at depth have decreased. The numbers of the rare and protected fish, the Arctic charr, have also declined dramatically in recent years. These changes have coincided with the population expansion of a lower-latitude, nonindigenous species, the roach. In this project we will test the hypotheses that the roach expansion is a result of the documented warmer waters in Windermere and that the population increase has triggered a 'trophic cascade' leading to greater predation on the zooplankton, which in turn has reduced the algae from control by their grazer. We will also test whether the decline in Arctic charr numbers results from competition with roach, since both feed on the zooplankton. We are in a unique position to assess the long term ramifications of multiple stressors because of the wealth ecological and environmental data and preserved samples collected from Windermere for most of the last century. The project will involve targeted, detailed analysis of the long-term data, analysis of the historical archived fish and zooplankton samples, identification of food sources of the different fish populations and food-web structure using stable isotope analysis and studies of fish gut contents, hydroacoustic analysis to estimate fish density and location and modelling to estimate roach ecological niche, zooplankton grazing and algal growth. The project is relevant to current general ecological issues such as the importance of top-down-control, the effects of multiple stressors and possible species extinction caused by species invasion. The results will also be highly relevant to the management of lakes since if our hypotheses are correct, nutrient removal will need to be even more stringent in the face of climate change and disruption of food-chains caused by invasion of nonindigenous species.