The goal of our proposed research is to understand how long-term warming of stream ecosystems influences their response (i.e., resistance and resilience) to increasing prevalence and intensity of hydrologic drought. Anthropogenic greenhouse gas emissions from human activities are generating both a rise in global temperatures and an increase in the frequency and intensity of extreme climatic events. While shifts in these drivers are known to affect the structure and function of running waters separately, few studies have investigated their combined or interactive effects. The prevailing view is that warming and drought will combine to produce more extreme ecological consequences than would result from either stressor alone. Yet, emerging evidence suggests that warming may trigger 'compensatory' responses - both adaptive and ecological - that may have the potential to lessen the impacts of extreme drought. Our collaborative NSFDEB-NERC project will combine laboratory measurements (University of Iceland), stream mesocosm manipulations of temperature and drought (University of Birmingham, U.K.), and whole-reach drought manipulations (Hengill geothermal catchment, Iceland) to test the overarching hypothesis that long-warming enhances stream ecosystem stability (both resistance and resilience) in response to drought events. Our first objective is focused at the individual level, investigating whether physiological adaptations to warming influence invertebrate carbon use efficiencies and their role in drought resilience and recovery. Our second objective seeks to quantify resistance and resilience of entire invertebrate communities and their biomass production in response to drought across natural and experimental thermal gradients. Our final objective will explore the potential for ecosystem-level compensatory responses by examining how warming-induced shifts in nutrient supply and primary producers influence stability of ecosystem metabolism and nitrogen uptake in response to drought.

Photodynamic therapy (PDT) is an established method for treating a variety of cancers (particularly lung, head, neck and non-melanoma skin cancer) and for treating a disease known as acute macular degeneration (AMD), which is the main cause of blindness in people over 50. PDT is carried out by injecting a dye into the patient, then irradiating the sick region of the body with red light. The light energy is absorbed by the dye and transferred to molecular oxygen generating excited singlet oxygen, which kills the surrounding cells. Light consists of particles called photons. Normally dyes absorb just one photon at a time, but at high light intensities, some molecules are able to absorb two photons simultaneously in a process known as 'two-photon absorption' (TPA). The possibility of carrying out PDT by TPA should make this type of therapy more applicable to deeper tumours, and to cases where spatial selectivity is critical, such as brain tumours and abnormal blood vessels in the eye (AMD). Recently we have shown that a class of dyes known as 'conjugated porphyrin oligomers' have unique advantages for two-photon PDT, and for one-photon PDT at near-IR wavelengths. The primary objective of this follow-on project is to gain understanding of the efficacy of these drugs, particularly for the treatment of tumours. We will also demonstrate that these compounds can be synthesised on a suitable scale for future pre-clinical and clinical trials. These advances are critical for making the technology attractive for commercialisation through licensing agreements.

It is widely recognized that prey populations can be limited not only by direct predation, but also by the costs of avoiding predation ('risk effects'). Logic suggests that risk effects might also exist in competitive interactions. We propose to test whether the avoidance of risk carries energetic costs that translate into effects on survival, reproduction, population dynamics and gene flow in a subordinate competitor, the African wild dog. We will do this by incorporating new methods into our ongoing long-term studies of African wild dog, lion and prey populations in three ecosystems. Specifically, we will couple direct observation of wild dogs to data from animals equipped with GPS collars, high frequency triaxial accelerometers and magnetic field intensity sensors, which, together, will give us very fine-scaled data on movement, dynamic body acceleration, energy expenditure and energy gain for wild dogs hunting in areas with known densities and distributions of lions and prey. Triaxial accelerometers will provide detailed and precise measurements of vectorial dynamic body acceleration (VeDBA), a powerful proxy for energy expenditure at time scales ranging from seconds to days or months. GPS collars will provide inferences on space use and movement from movement models (particularly dynamic Brownian bridge models - dBBMMs) at time scales from hours to years. These models of movement models, fit to trajectories derived from a combination of VeDBA, magnetic field intensity and GPS locations using a process termed 'dead-reckoning' (where animal movement patterns are derived from using vectors on movement data), will test for effects on movement down to the scale of seconds. Direct observation of the same individuals in continuous three-day 'follows' will provide spatiotemporally matched data on encounters with prey, hunts and kills to quantify energy gain at time scales from hours to years, and will provide critical context for the interpretation of other data. By pairing these data with intensive, long-term monitoring of known individuals, we will test relationships with survival, reproduction and population dynamics (using a Bayesian integrated population model), and effects on gene flow using a SNP chip we have developed and validated. With replication across three ecosystems with well-measured variation in the densities of competitors and prey, we will obtain data for a range of ecological conditions that would not be possible with a single site.

Microbes live wherever water is found at the Earth's surface, and the water found at the beds of ice sheets and glaciers is no different. Microbes grow beneath ice sheets, and help to convert the rock and sediment that glaciers crush up into fertiliser (N, P and Fe) that helps the microscopic plants in surrounding streams, lakes, coastal waters and oceans to grow. The microbes also produce greenhouse gases, such as carbon dioxide and methane. Just where the microbes which live beneath the ice sheets, for example in the subglacial lakes beneath Antarctica, get their energy to grow is a problem, since there is no light in these cold, dark habitats. The microbial communities beneath ice sheets are destined to die out unless something is continually supplying them with an energy source other than light. We think that "something" is something to do with glaciers crushing the rocks at their beds. The minerals are held together by tiny positive and negative electrical charges. These charges cancel each other out usually, but when the mineral is split by the huge weight of the glacier, their surfaces contain tiny positive and negative electrical charges, called radicals. These tiny charges are very reactive, so reactive that the positive charges grab OH from water and leave behind hydrogen gas, and the negative charges grab H from water and leave behind hydrogen peroxide. particular types of microbes enjoy feeding on hydrogen, since it produces lots of energy. The hydrogen peroxide is not immediately friendly to microbes, but it does react very well with organic matter in the crushed rock, producing carbon dioxide and other small organic molecules that microbes can use for energy sources. Some microbes combine hydrogen gas with carbon dioxide to make methane, and other microbes can use the methane as an energy source. So, the crushing and wetting of rock by glaciers and ice sheets produces a set of chemicals that can be used as energy sources by lots of different bacteria. Glaciers and ice sheets crush their bedrock continuously, and so we believe that this gives a continuous source of energy and chemicals to microbes living at their beds. We need to test these ideas by crushing simple rocks, such as quartz, and organic matter, such as peat, in the laboratory and measuring what types of chemicals come off the crushed material when we add water to it. If we're right, this will be a big step in understanding how life persists under glaciers and ice sheets. This is important, because in the past, when the earth was completely frozen on Snowball Earth, life was likely to have persisted under the ice sheets that covered large parts of the land surface. We hope that a Nuclear Winter never arises, but if it did, life in the form of microbes would persist beneath the ice sheets. Ice sheets occur on planets in the Universe apart from Earth, and it just might be crushing provides the chemicals to sustain life beneath them. CRUSH2LIFE will test whether we are right in thinking that these examples have any substance.

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