The Land Ocean Carbon Transfer (LOCATE) programme has established genuinely new and highly effective collaborations across NOC, CEH, PML and BGS to deliver new understanding of terrigenous dissolved organic matter (tDOM) fluxes across streams, rivers, estuaries and into coastal seas and the global ocean. These fluxes collectively represent a significant and changing, yet poorly understood, component of the global C cycle. Together, we have already achieved the following, major advances: 1) the first internally consistent integration of tDOM fluxes to the tidal extent of GB rivers, demonstrating that coniferous forestry in uplands enhances this flux; 2) the largest study of tDOM transport across temperate estuarine waters, highlighting that the composition and fate of this material is strongly influenced by human activities on land; 3) the most comprehensive assessment of the distribution of tDOM throughout the North Sea, identifying that the bulk of tDOM exported from the Northwest European and Scandinavian landmasses must be buried or remineralized internally, with potential losses to the atmosphere; 4) the development of a fundamentally new model, UniDOM, that unifies concepts, state variables and parameterisations of tDOM turnover across the land-ocean aquatic continuum (LOAC). Our developments in understanding the fluxes and fate of tDOM have brought into sharp focus how little is known about greenhouse gas (GHGs; CO2, CH4, N2O) fluxes and the processes that control these in aquatic ecosystems. Our key stakeholders, including BEIS and major water companies, recognise that this lack of understanding hinders national GHG emissions reporting and the development of sustainable land- and water management policies to enable the UK government to achieve net-zero GHG emissions by 2050. Building upon our previous achievements, our proposed extension activities aim to: 1) develop a GHG budget for the GB LOAC, 2) understand the biotic and abiotic processes that control these, and 3) assess the influence of human activities. We will achieve these through a series of interconnected objectives that combine desk-based syntheses and modelling activities, analysis of archived samples from our original year-long GB-scale field programme, use of our legacy focal catchments to establish a suite of baseline observations, and stakeholder engagement. We will continue to work with our diverse range of regional, national and international stakeholders to identify where and how this new understanding can achieve beneficial outcomes for policies and practices relating to C sequestration and climate regulation.

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.

Sea and society interact most strongly at the coast where communities both benefit from and are threatened by the marine environment. Coastal flooding was the second highest risk after pandemic flu on the UK government's risk register in 2017. Over 1.8 million homes are at risk of coastal flooding and erosion in England alone. Extreme events already have very significant impacts at the coast, with the damage due to coastal flooding during the winter 2013/14 in excess of £500 million, and direct economic impacts exceeding £260 million per year on average. Coastal hazards will be increasing over the next century primarily driven by unavoidable sea level rise. At the same time, the UK is committed to reach net zero carbon emissions by 2050. It is therefore essential to ensure that UK coasts are managed so that coastal protection is resilient to future climate and the net zero ambition is achieved. Protecting the coast by maintaining hard 'grey' defences in all locations currently planned is unlikely to be cost-effective. Sustainable coastal management and adaptation will therefore require a broader range of actions, and greater use of softer 'green' solutions that work with nature, are multifunctional, and can deliver additional benefits. Examples already exist and include managed realignment, restoration of coastal habitats, and sand mega-nourishments. However, the uptake of green solutions remains patchy. According to the Committee on Climate Change, the uptake of managed realignment is five times too slow to meet the stated 2030 target. Reasons are complex and span the whole human-environment system. Nature-based solutions often lack support from public opinion and meet social resistance. Despite removing long-term commitment to hard defences, the economic justification for green approaches remains uncertain due to high upfront costs, difficulty in valuing the multiple co-benefits offered, and uncertainties inherent to future environmental and socio-economic projections. The frameworks used to support present day coastal management and policy making (e.g. Shoreline Management Plans) do not provide comprehensive and consistent approaches to resolve these issues. Consequences are that the effectiveness of these policy approaches is reduced. Delivering sustainable management of UK coasts will therefore require new frameworks that embrace the whole complex human-environment system and provide thorough scientific underpinning to determine how different value systems interact with decision making, how climate change will impact coastal ecosystem services, and how decision support tools can combine multiple uncertainties. Co-Opt will deliver a new integrated and interdisciplinary system-based framework that will effectively support the required transition from hard 'grey' defences to softer 'green' solutions in coastal and shoreline management. This framework will combine for the first time a conceptual representation of the complex coastal socio-ecological system, quantitative valuation of coastal ecosystem services under a changing climate, and the characterisation of how social perceptions and values influence both previous elements. Our new framework will be demonstrated for four case studies in the UK in collaboration with national, regional, and local stakeholders. This will provide a scalable and adaptive solution to support coastal management and policy development. Co-Opt has been co-designed with project partners essential to the implementation and delivery of coastal and shoreline management (e.g. Environment Agency, Natural Resources Wales, NatureScot, coastal groups) and will address their specific needs including development of thorough cost-benefit analyses and recommendations for action plans when preferred policy changes. Co-Opt will further benefit the broad coastal science base by supporting more integrated and interdisciplinary characterisation of the complex coastal human-environment system.

This proposal seeks to understand how a prodigious 1,250 km runout submarine sediment avalanche (turbidity current) was triggered on 14th January 2020, by the largest flood in 50 years along the Congo River. This submarine flow broke two seabed telecommunication cables that underpin data traffic to West Africa causing the internet to slow from Nigeria to South Africa. These submarine cables had not previously broken in the last 20 years. This flow also caused a series of oceanographic moorings to surface, placed along Congo Submarine Canyon by a NERC project (NE/R001952). Cable breaks and surfaced moorings show that this remarkable flow ran out for over 1,200 km, as measured along the canyon axis. Moreover, the flow continuously self-accelerated, such that it reached front speeds of >8 m/s, some 1,150 to 1,250 km from its source at the mouth of the Congo River. This is the longest runout turbidity current yet monitored in action, and the only monitored flow to continuously self-accelerate for over a thousand kilometres. It is important to understand how such powerful and very long runout turbidity currents are triggered, especially for hazards to strategic seabed cables, including cable routes that are planned for 2020-21 off West Africa. The January 14-16th submarine flow is not associated with an earthquake, and it occurred during a period of low wave heights. However, it does coincide with an extreme flood of 80,000 m3s-1 observed in December 2019 along the Congo River. It is thus also important to determine how the frequency of submarine flows will be effected by future climate and hydrological changes in the Congo Basin. Here we seek to understand how this exceptional river flood triggered a thousand kilometre submarine flow, by conducting a detailed survey of the Congo River mouth. We will use the geomorphology of that river-to-submarine-canyon transition to understand how the offshore flow was triggered by the river flood, for example by mapping landslide scars, or testing a hypothesis that river bedload was driven over a single steep avalanche face. This is an urgency grant because evidence of how the Jan 2020 flow was triggered (e.g. seabed failure scarps) will be buried or wiped-out by the next peak discharge of the Congo River in Oct 2020. There are extremely few direct measurements of the most powerful turbidity currents that run out for hundreds to thousands kilometres to the deep ocean, and the few measurements available previously produced step changes in understanding. Indeed, there has only been one previously directly-measured turbidity current on this scale, which is the Grand Banks event in 1929 that broke all ~20 cables across the N. Atlantic. The Grand Banks event ran out for over 800km, but decelerated from 19 m/s to 3 m/s, rather than continuously accelerating as in the Jan 2020 event. Moreover, the Jan 2020 event already has much more detailed measurements from the timing of offshore moorings, with further data to come via recovery of these moorings and 12 OBS (with hydrophones and geophones) on a NERC cruise. This Jan 2020 event is thus a rare and extremely valuable opportunity to understand how far large-scale flows operate, linked to exceptional river floods with much longer (50-100 year) recurrence intervals. The main gap in our understanding of the Jan 2020 event is what happened at the river mouth, and this is key for predicting flow frequency and links to climate change. The geomorphology of the river to canyon-head transition is currently unknown. For example, UKHO bathymetric charts mainly use data collected in the 1890s. Here we will use swath multibeam echosounder systems to survey the river to canyon transition at much higher resolution and in three dimensions, thereby documenting its geomorphology in unprecedented detail. Past work shows how a single multibeam bathymetric survey can produce major insights into turbidity currents triggering at river mouths.

Meeting energy demands in the most sustainable way is a major challenge for society. Offshore wind farms - groupings of wind turbines on submerged sediments - offers part of the solution for the energy transition that is needed to mitigate climate change, and the UK has committed to a dramatic and rapid expansion of wind farms in the seas around the UK. However, shelf sea sediments host diverse and productive communities that play a very important role in processing nutrients and carbon that underpin the entire food web. Many species are also important prey items for higher trophic levels, including sea mammals and birds. At the same time, many sediment-dwelling species, such as clams, worms, shrimp and some fish are so intimately associated with the sediment environment that they are particularly susceptible to disturbance. This raises concern as the expansion of offshore wind currently underway means that marine ecosystems are highly likely to experience a large proportional change in biodiversity and ecosystem functioning if marine policy and the management of increasing pressures on UK marine ecosystems is not correctly guided. In this project, we have assembled marine ecologists, engineers and computational scientists to work together to understand ecosystem responses to the cumulative pressures of a large increase in deployment of offshore wind, considered in combination with other pressures that marine ecosystems are facing caused by human activity (bottom fishing, shipping) and the effects of climate change (acidification, warming, low oxygen). To do this, we will collate available data on many aspects of the marine environment and fill in gaps in these data by collecting targeted information about how species interact and behave around offshore wind structures using autonomous vehicles and use artificial intelligence algorithms to identify any associations and patterns. This analysis will also tell us which species are vulnerable to change and highlight areas of concern. Next, we will carry out a series of experiments that will test whether representative species are susceptible to certain types of noise and vibration, electromagnetism and localised heating which are common sources of disturbance associated with wind farms. We will also bring back intact assemblages from areas experiencing different levels of fishing intensity and expose them to the same pressures to see whether species that are experiencing one set of pressures will respond in the same way as those that are not experiencing other pressures. This will tell us how species respond under current conditions, but the pace of climate change means that an additional set of pressures will also effects these species. Hence, we will carry out the same experiments under simulated future conditions (warmer and with altered seawater chemistry). The results of these experiments will tell us whether species benefit or are compromised by certain combinations of pressures, and our expectation is that some species and communities will fair better than others. We will use this information to develop models that allow us to predict how other species that we have not considered, but which share similar traits, may respond. To do this we will use sophisticated statistical models that take into account wider information and make predictions about what marine systems in the future might look like in the future under different scenarios of habitat use, human activity and climate change. In a final step, we will develop a decision support tool that will allow the complexities, including positive and negative feedbacks, to be taken into account by decision and policy makers so they can see the likely consequences of consenting offshore wind in specific locations. Our tool will support the sustainable growth of the offshore wind industry by helping decision makers to make informed decisions that minimise pressure on our marine ecosystems.