Ocean acidification due to the dissolution of anthropogenic CO2, and the effects of cumulative stressors (including acidification, pollution, warming, and anoxia) are among the top priorities for ocean research, requiring accurate and consistent measurements across the globe to monitor and understand present effects, and modelling to evaluate future scenarios and methods of remediation. The work of observational scientists and modellers is linked by the need for an accurate knowledge of the chemical speciation of the inorganic carbonate system, pH, and nutrient and contaminate trace metals, in both natural waters and the reference materials and solutions used for instrument calibration. Chemical speciation is defined as the distribution of a chemical element between different molecular and ionic forms in seawater, and determines its reactivity and bioavailability. Speciation depends on the value of the relevant thermodynamic equilibrium constant, and on the activities of each of the dissolved ions and molecules. These are complex functions of temperature, pressure, and salinity (or, more generally, solution composition), and cannot be predicted from theory. Many of the important reactions in seawater involve acid-base equilibria, which introduces pH as an additional variable. Despite the importance of chemical speciation, the available calculation tools are often only simple empirical equations that yield equilibrium constants for reactions as functions of salinity and temperature. Such equations cannot be used for many important natural waters whose composition differs from that of normal seawater (e.g., polar brines, estuaries, pore-waters, enclosed seas, and paleo-oceans). Furthermore, human-driven changes in seawater pH and carbonate chemistry in shelf seas and estuaries are complicated by the effects of eutrophication, upwelling, the dissolved solutes contained in river water, and changes in metal toxicity accompanying pH change. Consequently, despite the best efforts of physical chemists over the last several decades, there is not yet the ability to calculate the equilibria controlling the chemical factors impacting shellfish and a broader range of marine fauna in the brackish/mesohaline environments typical of many estuaries and coasts. We will create a step change in the capability of marine scientists to measure, interpret, and predict chemical speciation and pH in natural waters of varying composition by creating a speciation model based upon the Pitzer equations for the calculation of solute and water activities. The approach has a long track record of success in geochemistry. The equations are based upon the concept that interactions between pairs and triplets of dissolved solute species control activities. The values of the parameters for these interactions are determined from a wide range of measurements of solution properties. Work in this project will include measuring activities and heat capacities, and using recent literature data, to improve and test the model; the computer coding and validation of the model and the development of methods to quantify the relationship between uncertainties in model-predicted speciation and those in the underlying measurements; and engagement with oceanographers internationally to help design practical speciation modelling tools and associated guidance for specific applications. The completed model will enable the activities and speciation of all seawater components to be calculated within a unified framework that, (i) includes the major and trace elements in seawater and its mixtures with freshwaters, (ii) includes other saline environments of differing composition, and (iii) encompasses the buffers that are used to calibrate pH and other instruments, and. Our results will this advance the quantitative understanding of chemical speciation - from ocean measurements to ecosystem models - for an expanded range of natural water bodies and marine environments.

The UK Government is committed to reducing greenhouse gas emissions and protecting the environment. Delivering on these parallel objectives, however, involves numerous tensions. Future low-carbon energy pathways that, for example, depend on the sourcing of feedstocks through hydraulic fracking have implications for the availability of clean water and hence for the ecosystem services such resources provide to other industrial, domestic or agricultural users. Likewise, pathways that envisage more wind farms have implications for the quality of the natural landscape and the cultural ecosystem services people derive from the visual enjoyment of those landscapes. The central objective of this project is to explore future UK low-carbon energy pathways and quantify their differing implications for stocks of natural capital (e.g. groundwater and natural habitats) and for the provision of ecosystem services (e.g. irrigation, visual amenity, recreation). In addition, the project will apply methods of economic valuation to estimate in money terms the value of the ecosystem service changes associated with different future energy pathway. Ultimately, the project seeks to provide policy makers with tools that allow them to take a whole-systems perspective on energy futures in a way that integrates energy and environmental considerations into a single framework. The research programme will begin with workshops bringing together members of the valuing nature and energy futures research communities. The aim will be to encourage discussion between the participants and to arrive at a shared understanding of the conceptual framework that should underpin the research as well as to establish the baseline of existing knowledge. Part of that knowledge base will be a description of the particular future energy pathways to be explored in the project. The next task for the research team will be to develop a detailed life cycle characterisation of each pathway. Drawing on previous research, the project will then identify the anticipated ecosystem service impacts of each particular element of a pathway. And, where available, collate evidence regarding the estimated value of those various impacts. For numerous elements, however, those impacts and/or values may be unknown. Indeed, the project will seek to fill those knowledge gaps through a set of case studies. These will explore aspects of bioenergy, carbon capture and storage, visual disamenity, impacts on marine recreation biodiversity consequences and the impacts of infrastructure to reduce energy demand. Drawing on the results, the research will then seek to integrate the available evidence so as to assess the environmental impacts of each energy pathway in its entirety. To that end, the project will build on previous work by extending two complementary modelling platforms. The first is a micro-economic model that allows for a spatially-disaggregated exploration of the impacts of each pathway. The second employs macro-economic modelling to understand how natural capital use in different pathways impacts on the broad functioning of the economy and concomitant implications for growth, jobs and trade. To provide a holistic assessment of each pathway, a further work stream will quantify the international implications for natural capital and ecosystems services of UK decisions on future energy systems. The findings will be made available to academics and policy makers through an extensive programme of dissemination and knowledge exchange. In addition, through training a cohort of PhD studentships, the project seeks to leave a legacy of academic capacity focused on the interface between energy and the environment. Together, the new knowledge and expertise delivered by the project will provide a major contribution to ensuring that energy and natural capital policies can be developed in a coherent manner for the maximal benefit of society as a whole.

Biological productivity (the growth of phytoplankton) is limited by the availability of iron (Fe) in at least 30% of the ocean. Fe is so insoluble in seawater that the large amounts entering from rivers cannot be transported far from the continental margins. The supply of Fe from dust falling on the ocean becomes the primary way to add Fe (and other elements important to life such as phosphorus) to the open ocean. The pattern and flux of Fe from the atmosphere to the surface ocean is therefore important for ocean ecosystems, and for the global carbon cycle (because ocean life consumes carbon). Despite this importance, the flux of dust and of its incorporated metals to the ocean is poorly known. It is challenging to measure this flux directly, and other observational approaches require quite fundamental assumptions, which limit accuracy. At present, therefore, most estimates of dust flux rely on atmospheric models, and are generally considered to be uncertain by a factor of ten, particularly in remote regions. In the proposed work, we will assess and use a new approach to quantify the inputs of dust and its associated micronutrients to the ocean. This approach relies on measurements of two biologically inactive, partially soluble components of dust: thorium (Th) and aluminium (Al). Two isotopes of Th are used in this assessment. 232Th, is present in continental rocks. If found dissolved in the open ocean, 232Th must have been recently added by dissolution of dust transported from the continents. Another isotope, 230Th, is formed within seawater by the decay of a uranium isotope. Its concentration in seawater reflects a competition between this known rate of formation, and removal due to its insoluble nature. We can therefore use 230Th to assess the removal rate of Th, including 232Th, from seawater. The 232Th removed must be replaced by input from dust to maintain the observed 232Th concentrations, so we can calculate the input of dust. There are two main challenges to the reconstruction of dust fluxes from Th isotopes. One is that the solubility of Th in dust, a critical term in the flux calculation, is not well known. Our new results indicate that Th is amongst a small group of elements whose solubility is very little impacted by transport of dust through the atmosphere, while the solubilities of Fe, Al and several other biologically active elements are all altered greatly during transport. Using aerosol samples collected on a series of research cruises, and at a sampling tower on Bermuda, we will assess the solubility of Th, the controls on how that varies during atmospheric transport, and its relationship to changes in Al and Fe solubility. We will also conduct laboratory studies on desert dust parent soils aimed at better understanding the unusual Th solubility in dust aerosols. Dust fluxes can also be calculated from dissolved Al concentrations, but these estimates are affected by changes in Al solubility during atmospheric transport. The second challenge is that we do not know how far 232Th from the continents might travel after input at the coast. We will address this by incorporating 232Th into an ocean model. Such models have a proven ability to reconstruct 230Th, and we will develop them to also model 232Th, and to indicate where 232Th is dominated by coastal inputs rather than by dust. These models will also be used to assess the uncertainty in using Th isotopes to reconstruct dust inputs. A large number of observations of Th isotopes in seawater has recently been measured during an international programme: GEOTRACES. We will add data from two further cruises, to complete a detailed coverage of Th and Al measurements for the Atlantic Ocean. Combined use of the Th and Al tracers will therefore allow us to produce robust maps of dust inputs (from Th) and soluble Fe inputs (by taking account of the changes in solubility during transport using Al) for the Atlantic (with associated maps of uncertainty).

Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.

ACTNOW advances the state-of-the-art in understanding and forecasting of the cumulative impacts of climate change and interacting drivers on marine systems. The program provides solutions options to halt the loss of biodiversity, to restore and protect habitats and ecosystem processes, and to safeguard the contributions of marine areas to human well-being. ACTNOW is co-developed with EU policy stakeholders to deliver: 1) Mechanistic (cause-and-effect) understanding of the impacts of multiple interacting drivers on organisms, communities, habitats and ecosystems from individual-level performance to ecosystem-level stability, resistance, resilience and tippingpoints; 2) Improved monitoring and new indicators of marine biodiversity based on state-of-the-art biologging technology, molecular methods and advanced numerical modeling; 3) Enhanced forecasts of European marine biodiversity, ecosystem functioning and services using scenarios (co-created and regionalized with practitioners) of multiple drivers and management settings, as well as integrated impact assessment methods; 4) Fit-for-purpose decision-support tools enabling regulators to deliver regionally-appropriate assessments and actions to restore and maintain Good Environmental Status; 5) Next-generation training for early-career scientists working on solutions to the dual crises of biodiversity loss and climate change and capacity building to enhance public literacy on the One Health concept. ACTNOW builds predictive capacity of multiple driver effects and performs integrated indicators assessments of biodiversity across 20 Case Studies capturing all European climate zones and regional seas, including pan-European research on key groups in marine food webs. dies capturing all European climate zones and regional seas, including pan-European research on key groups in marine food webs.