National Oceanography Centre

Managed realignment is an effective solution in coastal management. This typically involves breaching existing coastal defences, allowing flooding of previously protected land and creation of intertidal habitat, and relocation of the line of actively maintained defences inland. In the UK, creation of intertidal habitat by managed realignment is recommended by strategic plans, yet the uptake of schemes is not keeping pace to meet self-selected targets. The underlying reasons for this slow uptake are complex, span multiple interacting disciplines and are not fully understood. A critical aspect relates to the long-term sustainability and success of the scheme. We explore here how the response of managed realignment to climate drivers leading to intended and unintended consequences intersect with community perceptions.We focus on a case study in the UK (Hesketh Out Marsh in the Ribble Estuary) where we integrate community co-production with quantitative modelling and long-term environmental datasets. We bring together outcomes from co-creating a shared understanding of the managed realignment system with stakeholders and the local community, with results from downscaled hydrodynamic modelling of the Ribble estuary under present and future sea level, and with LiDAR and Sediment Erosion Table datasets for Hesketh Out Marsh.Our results show that the managed realignment have both positive and negative influences on the overall social-ecological system. Hydrodynamic modelling results show significant spatial variability in the effect of the managed realignment scheme, which is amplified by sea level rise. In some areas, managed realignment is beneficial but in others it is not. The newly created saltmarsh is slowly accreting, which is beneficial against sea level rise and its long-term viability, but impairs drainage of its terrestrial hinterland. Workshops with local stakeholders revealed entrenched and conflictual perceptions of the process, goals, and effectiveness of the managed realignment scheme. Altogether, this demonstrates the complexity inherent to managed realignment social-ecological systems. Transdisciplinary approaches are critical to better incorporate this complexity into management approaches by enabling to bring together multiple voices and knowledges and to co-create a clearer, more complete shared understanding of the system.

The far-reaching benefits of citizen science are widely recognized: from empowering individuals to actively contribute to new scientific knowledge, to building relationships and trust between scientists and the public, to the health gains of simply spending time in nature. At present, many citizen science projects take advantage of smart phones as low-cost and accessible method to harvest data over widespread geographical areas. However, limited interpersonal interaction presents a challenge when dealing with multifaceted issues such as invasive species.Here we review an ongoing citizen science project, which employs a ‘deep-learning’ pedagogy to interact with an unlikely audience. The ‘Oyster Hunt’ takes place in the Limfjorden, Denmark, and engages with both ‘gastro-tourists,’ i.e. those willing to travel to learn about regionally important foods, and the local community. Participants are given a short talk about the ecology of the fjord, before being sent into the water to take samples in and around an oyster reef. Bringing their samples back to sorting stations, the participants then count, measure and weigh data with university research scientists on hand to guide and discuss along the way before learning culinary skills from gourmet chefs. After eating their hunt, the citizen scientists also took part in a reflective survey, digesting what they had learnt that day, what they felt they had achieved and how they felt about themselves as citizen scientists. We present this project as a case study for an alternative citizen scientist approach, whereby a new audience is exposed to the challenges of the changing fjord, learns ecological sampling techniques and then actively engages with the subject through dialogue.The data collected by the citizen scientists provided a comprehensive look at the invasive pacific oyster community structure which has contributed to our understanding of this species in a unique microtidal environment. In addition to engagement with the participants (N=87 in 2025), the Oyster Hunt has provided a springboard for dissemination online, where the conversation continues. From this example, we propose a framework for developing similar memorable events, as well as providing critique onto our own approach: 1) identifying which issue to engage with; 2) developing a multi-sensory approach to interact with that issue; 3) considering resources needed and fun collaboration; and importantly 4) reserving time to talk and reflect. As a gastro-tourism citizen science collaboration, the oyster hunt not only provided a memorable day out for some, it also provided dedicated time and space to think together about the future of the fjord.

3D biogeochemical ocean models such as cGENIE can explicitly model depth-dependent carbon cycle processes, such as remineralisation of organic carbon. This potential advantage of 3D models (in comparison to box ocean models) can, however, be limited by coarse spatial resolutions. In particular, continental shelves may be underresolved in 3D model bathymetric grids. Such grids are created by downsampling (palaeo)-digital elevation models (DEMs).We develop an algorithm (here termed ‘DEM-based upsampling’) to project 3D ocean model output onto its associated DEM. This resolves depth-dependent quantities and fluxes at the seafloor at degree-scale and better captures shallow seafloor, including continental shelves. This is critical for modelling organic carbon cycling, as continental shelves receive more than half of the global flux of organic carbon to the seafloor. We validate the DEM-based upsampling algorithm using area-weighted errors between a modern-Earth model run and observational data (World Ocean Atlas 2023). Upsampling yields statistically significant reductions in error in modelled temperature, salinity, oxygen concentration, and phosphate concentration across bootstrap confidence intervals and paired non-parametric tests.We then derive the first spatially-resolved model record of ocean organic carbon burial from 25 Ma – present using the PhanerO3D framework, driving cGENIE with SCION biogeochemistry and HadCM3L atmospheric physics. We obtain organic carbon burial flux by upsampling cGENIE’s organic carbon export flux and applying a simple burial scheme. We find the global burial rate peaks in the early Miocene, then declines over the remaining Neogene. This trend agrees well with geochemical records until the latest Miocene – Pliocene. We find global variability to be largely driven by regional changes; notably declining North Atlantic margin burial over the Miocene, and rising West Pacific burial in the Pliocene.These results highlight the advantages of DEM-based upsampling as a tool in palaeoclimate modelling: better constraining depth-dependent ocean processes, facilitating deeper investigation of spatiotemporal patterns, and potentially facilitating more spatially precise proxy-model comparison.

High-resolution coastal ocean modelling is essential for understanding and managing complex coastal systems under increasing environmental and socio-economic pressures. We present the development of an unstructured FVCOM numerical model for the Shetland and Orkney archipelagos in the north of Scotland, with a hindcast run covering a 30-year period at unprecedented high resolution (~70m around the Shetland coast and hourly output), nested in the Scottish Shelf Model and fully-forced with 5.5km CERRA atmospheric data at hourly frequency. The unstructured grid allows to resolve the complex coastline and bathymetry that characterizes these areas. This region is paramount for the aquaculture industry, with Shetland alone making up for more than 20% of the Scottish salmon and more than 80% of Scottish mussel production, yet its energetic circulation, complex bathymetry, and strong coastal–ocean interactions make monitoring and prediction of potential environmental impacts particularly challenging. Combining numerical modelling with data science tools, we explore the system variability and complexity. This allows the identification of emergent patterns, dominant modes and changes that may otherwise be overlooked. Our work helps supporting more effective long-term monitoring and sustainable use of marine resources in a region increasingly affected by climate change.

Distributed acoustic sensing (DAS) has transformed geophysical, environmental, and infrastructure monitoring. However, the increasing bandwidth and sensitivity of modern interrogators now extend into the audio range, introducing a material privacy risk. Here we demonstrate, through in-situ experiments on live fibre deployments, that human speech, music, and other acoustic signals can be under certain acquisition conditions.We show that intelligible speech can be accurately recovered and automatically transcribed using neural networks. Experiments were conducted on both linear and spooled fibre geometries, deployed as part of an ongoing geophysical survey. We find that coiled layouts, which are common in access networks (e.g., slack loops or storage spools), exhibit enhanced sensitivity to incident acoustic waves relative to linear layouts. Modelling indicates this arises from increased broadside sensitivity and reduced destructive interference for longer wavelength acoustic fields over the gauge length. We systematically assess how acquisition parameters, such as source-fibre offset, influence signal‑to‑noise ratio, spectral fidelity, and speech intelligibility of recorded audio. We further show that neural network based denoising strategies improves intelligibility and fidelity of recorded audio, thereby exacerbating privacy concerns.These findings demonstrate that appropriate interrogation of existing fibre infrastructure - including fibre‑to‑the‑premises links, smart-city infrastructure, and research cables – can function as pervasive, passive wide-area acoustic receivers, creating a pathway for inadvertent or malicious eavesdropping. We discuss practical mitigation strategies spanning survey design, interrogation configuration, and data governance, and argue that the incorporation of privacy‑by‑design into deployment and processing is crucial to leverage the unique benefits of DAS while managing emerging ethical and legal risks.

The Cenozoic Era provides a key framework for investigating how ocean oxygenation and marine productivity responded to past global warming events, offering valuable analogues for ongoing and future climate change. Here, we integrate foraminifera-bound nitrogen isotopes (FB-δ¹⁵N) with stable carbon and oxygen isotopes (δ¹³C, δ¹⁸O) to reconstruct nitrogen-cycle dynamics, water-column oxygenation, and photosymbiotic behaviour in planktic foraminifera across the Middle Eocene Climatic Optimum (MECO; ~40 Ma), a major greenhouse interval lasting ~500–600 kyr. The dataset is based on planktic foraminifera from two Atlantic sites spanning contrasting latitudes: subtropical ODP Site 1051 and subantarctic ODP Site 702. FB-δ¹⁵N records from both sites show a marked and coherent decrease during the MECO, reaching minimum values at peak warming. This trend indicates a general reduction in water-column denitrification, a process that generally occurs under extremely low oxygen conditions, suggesting that prolonged warming was not associated with widespread deoxygenation in the global ocean . These results are consistent with patterns observed during other Cenozoic hyperthermals (e.g. PETM, EECO, MCO) and imply that enhanced deep-water ventilation and/or reduced biological productivity counteracted warming-driven oxygen loss. Paired δ¹³C and δ¹⁸O data confirm persistent vertical habitat partitioning among planktic foraminiferal taxa, despite partial convergence in δ¹⁸O values during the MECO, indicating upper-ocean thermal homogenization and temporary niche compression. This preservation of depth-related ecological structure supports the interpretation of interspecific FB-δ¹⁵N offsets as reflecting distinct symbiotic strategies. Lower δ¹⁵N values in Acarinina and Globigerinatheka relative to Subbotina confirm their photosymbiotic nature, while systematic differences between the two symbiotic genera suggest dinoflagellate symbionts in Acarinina and non-dinoflagellate algae (e.g. diatoms or coccolithophorids) in Globigerinatheka. The contrasting evolutionary trajectories of these taxa, recording a decline for Acarinina and expansion for Globigerinatheka during and after the MECO, likely reflect differences in symbiont flexibility and sensitivity to photic-zone environmental change. Overall, this study provides the first reconstruction of the nitrogen cycle across the MECO and demonstrates the value of FB-δ¹⁵N, combined with δ¹³C–δ¹⁸O constraints, as a dual proxy for local and global denitrification and planktic foraminiferal ecology during sustained greenhouse warming.

This poster provides an overview of the PROMOTE (Progressing Earth System Modelling for Tipping Point Early Warning Systems) project. One project aim is to develop a version of the UK Earth System Model (UKESM) that is suitable to become the model component of a potential early warning system of Subpolar Gyre or Greenland Ice Sheet tipping. In PROMOTE, we (i) undertake targeted development of UKESM to advance its representation of the Greenland Ice Sheet and North Atlantic Subpolar Gyre, (ii) develop innovative simulation techniques aiming to make the simulation of tipping behaviour in the Subpolar Gyre and Greenland Ice Sheet more controlled and efficient, (iii) use machine-learning and other analysis techniques as well as model simulations to inform the design of observational networks, and (iv) evaluate tipping processes and impacts of tipping in our newly developed model versions. PROMOTE is run by a team of scientists and model developers at 7 UK national research centres and universities during 2025-2030, and is part of the “Forecasting Tipping Points” programme funded by the Advanced Research and Invention Agency (ARIA).

The Reykjanes Ridge (RER) is a 1000 km-long slow-spreading segment of the Mid-Atlantic Ridge that extends southwest from the Reykjanes Peninsula, Iceland. The Icelandic mantle plume exerts a chemical and thermal influence on the ridge that varies spatially, expressed in systematic changes in glass geochemistry, magma flux, crustal thickness and magma storage depths along the ridge [1, 2]. The RER is arguably one of the best-studied segments of mid-ocean ridge globally. However, very little is known about the nature of magmatic processes along the RER. Specifically, we do not know whether there are systematic changes in the assembly, storage and transport of magmas along the ridge with varying proximity to the mantle plume.We present the first systematic investigation of magmatic processes along the RER with a geochemical and petrological study of mid-ocean ridge basalts (MORB) dredged from a ~900 km transect along the ridge. The crystal cargoes of these samples preserve records of recharge, mixing and ascent, as well as the pressure-temperature conditions of magma storage. We combine EPMA analyses with textural observations from BSE and EDS mapping to reconstruct the complex magmatic histories of individual crystals and of crystal populations. Zoning and resorption textures in individual crystals reveal how magmatic conditions changed during crystal storage and growth. We observe different types of crystal textures and different crystal populations that recur along the ridge, and we determine the spatial distribution of these variations.Our goal is to identify signatures of mush disaggregation and mixing between magma and crystal populations, and to assess whether the relative importance of these processes changes along the RER with proximity to the Iceland mantle plume. This work represents a new contribution to the relatively limited data on crystal cargoes in global MORBs, and will allow us to place constraints on how crystallisation and magma storage at mid-ocean ridges may vary according to magma flux, crustal thickness and mantle chemistry on a global scale.

The North Atlantic re-emergence phenomenon is an intermittent event in which winter sea surface temperature (SST) anomalies subduct under the seasonal thermocline and re-emerge the following winter when the mixed layer deepens. This means that the ocean acts as a `memory' for North Atlantic winter climate on interannual scales. Previous studies of the North Atlantic re-emergence phenomenon are limited by short observational records, forced-ocean models, or poor resolution. The CANARI Large Ensemble (65 years x 40 members of the UK Met Office Climate Model (HadGEM3) at N216 atmosphere and 1/4 degree ocean resolution) provides an opportunity to robustly analyse these events and their mechanisms. We have tested existing mechanistic theories, and are answering other pertinent questions, such as; does stratospheric preconditioning occur and can we harness predictability from it? Are there multi-year impacts and cascading effects? Can we quantify the relationship between Atlantic meridional overturning circulation (AMOC) and re-emergence?