This dataset provides yearly estimates of near-global (65N-65S) ocean heat content and thermosteric sea-level depth-integrated for the upper 700 meters of the ocean for 1970 - 2023. The yearly values are presented with three-year smoothing and one-sigma error estimates. The dataset builds upon and updates the methodology established in Domingues et al. (2008, Nature), incorporating temperature measurements from ocean observation systems and applying corrections for instrumental biases and sampling irregularities. To estimate ocean heat content for the upper 700 m and the associated thermosteric sea level, we used ocean temperature profiles from the ENACT/ENSEMBLES version 3 (EN3) data set (1970-2004), and Argo/Ifremer profiling floats (2000-2023, updated January 2024). Empirical Orthogonal Functions (EOFs) were used to model variability of the time-varying sea level and were calculated from 23 years (1993–2015) of satellite altimeter data sourced from Commonwealth Scientific and Industrial Research Organisation (CSIRO), (TOPEX/Poseidon, Jason-1, Jason-2 and Jason-3).

The CreamT project converted the prototype WireWall wave overtopping field measurement system into a ruggedised monitoring system between August 2020 and August 2023. The system was deployed for up to a year in two high-energy coastal environments along the Southwest coast, UK (Dawlish and Penzance). The system was designed to have a 3-month maintenance interval and was programmed to measure overtopping condition ±3hrs either side of predicted high tide. The wave-by-wave overtopping data were telemetered to the British Oceanographic Data Centre (BODC) every 10 minutes. At the time of the project, the coastal structures at these sites comprised a vertical sea wall with small return lip or curve at the top. Both sea walls were fronted by a beach. During the project period the Dawlish beach levels exposed a concreate toe at the base of the wall. In Penzance, the beach covered the sea wall toe and was higher in the southwest monitoring location. The system was designed at the National Oceanography Centre (NOC) and had previously been validated in HR Wallingford’s flume facility and field tested with Sefton Council (https://www.channelcoast.org/northwest/). During CreamT, three different system configurations were deployed: full WireWall systems each with an array of six capacitance sensors; smaller WireWand systems with two capacitance sensors mounted on a single pole to detect overtopping at hazard hotspots; and a WaveWell using a single sensor on the face of the sea wall. Six datasets are available from the CreamT project. These contain delayed mode data from: 1) a WireWall deployed at the crest of the sea wall in Dawlish; 2) a WireWand deployed at the wall just seaward of the railway line in Dawlish; 3) a WireWand deployed at the fence just inland of the railway line in Dawlish; 4) a WaveWell deployed on the face of the sea wall in Dawlish; 5) a WireWall deployed at the crest of the sea wall in Penzance near Queen’s Hotel, and; 6) a WireWall deployed at the crest of the sea wall in Penzance near the Lidal store at Wherrytown. The datasets in Dawlish provide information about the inland distribution of overtopping, and the two datasets in Penzance provide information about the alongshore variability in overtopping hazard. These data can be used alongside the regional monitoring data available from the Southwest Regional Monitoring Programme to investigate the drivers of wave overtopping. All these data can be visualised in a hazard dashboard developed by the BODC and hosted on JASMIN, https://coastalhazards.app.noc.ac.uk/. This project was delivered by the National Oceanography Centre in collaboration with BODC and the University of Plymouth under NERC Grant References NE/V002538/1 and NE/V002589/1. Project partners were Network Rail, Southwest Regional Monitoring Programme, Environment Agency and Channel Coastal Observatory.

Multibeam bathymetry data were collected in the Clarion-Clipperton Zone (CCZ), Northeast Pacific Ocean, using a hull-mounted Kongsberg EM122 multibeam echosounder during RRS James Cook Cruise JC241 from 06/02/2023 to 25/03/2023, and JC257 from 08/02/2024 to 19/03/2024. Data acquisition began upon exiting the Costa Rican Econoic Exclusion Zone (EEZ), suspended within the Clipperton Island EEZ, and resumed upon exiting the Clipperton Island EEZ. Data were then acquired throughout the CCZ. This suspension was repeated on the return journey. The data were recorded using Kongsberg’s Seafloor Information System (SIS) in .all format, and CTD and model-derived sound velocity profiles were subsequently applied. The data were manually cleaned using swath and subset editors in CARIS HIPS and SIPS software version 10.4. A zero tide file was also applied. The data were collected to obtain a better insight in the biodiversity patterns and benthic habitat distributions within the CCZ, by scientists from the National Oceanography Centre, Southampton, UK as part of the NERC-funded Seabed Mining And Resilience To EXperimental impact (SMARTEX) project (NE/T003537/1).

This dataset provides modelled storm surge and total water levels along the South China Sea region (coastline of China, Vietnam, Cambodia and Thailand) for the period 1980-2050. Three return period scenarios are considered: 10% AEP (Annual Exceedance Probability) = 1:10 year return period; 1% AEP = 1:100 year return period; 0.1% AEP = 1:1000 year return period. Projections utilise Representative Concentration Pathway (RCP) 8.5 – the greenhouse gas concentration trajectory adopted by the Intergovernmental Panel on Climate Change (IPCC). The dataset was produced by forcing a hydrodynamic model underpinned by a new synthetic database representing 10,000 years of past, present and future tropical cyclone activity. The aim of this exercise being to estimate the risks posed by extreme sea levels, especially in tropical regions where cyclones can generate large storm surges and observations are too limited in time and space to deliver reliable analyses. The dataset was produced by Principal Investigators Dr Ivan D Haigh and Dr Melissa Wood (School of Ocean and Earth Science, University of Southampton, UK) in collaboration with partners from the School of Geography and Environmental Science (University of Southampton, UK), Tyndall Centre for Climate Change Research (University of East Anglia, UK), Southern Institute of Water Resource Research (Vietnam) and the Institute for Environmental Studies (Netherlands). Funding was secured through the UK’s Natural Environment Research Council (NERC) Grant ‘CompFlood’ (grant number NE/S003150/1).

This dataset contains the measurements of sea level made by Nevil Maskelyne on the Island of St. Helena from 12 November to 22 December 1761, as published in his Philosophical Transactions of the Royal Society paper of 1761 (https://doi.org/10.1098/rstl.1761.0100). The data values presented were transposed from the information in Maskelyne's original paper into the data file included with this submission by the authors of this dataset. The data have been subjected to various types of quality control by the authors including, in particular, consistency of the tidal content of the sea level time series with modern expectations, and the data have been studied within a modern reanalysis (submitted for publication). The purpose of this dataset is to make the Maskelyne measurements more accessible in an electronic form for the benefit of future researchers.

Two laboratory experiments were conducted at the National Oceanography Centre in Southampton from June 2021 - April 2022 to investigate intraspecific variability in functional trait expression in marine bioturbating benthic invertebrate fauna. The macroinvertebrate species Amphiura filiformis, Amphiura chiajei, Turritellinella tricarinata, Edwardsia claparedii, Sternapsis scutata, Paraleptopentacta elongata, Hediste diversicolor and Nephtys hombergii were collected from different locations around the UK (Plymouth, Oban and Newcastle) and in two different seasons. In laboratory experiments ranging in duration from 2 - 3 months we investigated how individual densities, season and future vs ambient climate treatments impacted functional bioturbation behaviour and ecosystem functioning (nutrients release and community respiration).

Two collections of benthic still images were obtained using a downward-looking camera mounted on the UK ISIS Remotely Operated Vehicle (ROV), deployed from the RRS James Cook during cruise JC241, 2023. Two further benthic still image collections were acquired using the UK Autosub5 Autonomous Underwater Vehicle (AUV), deployed from the RRS James Cook during cruise JC257, 2024. All surveys were undertaken in the abyssal plain of the Clarion-Clipperton Zone (CCZ), Pacific Ocean (~4100-4700 m depth). The Grasshopper2 GS2-GE-50S5C camera system was mounted on each vehicle and captured vertically orientated still images at a target altitude of 2.5 - 3 m above the seabed. One ROV survey from JC241 was undertaken to assess benthic biological patterns in an area disturbed by a deep-sea mining machine operated by the Ocean Minerals Company (OMCO) in 1979. The second ROV survey from JC241 and one AUV survey from JC257 was undertaken in the UK-1 exploration area. The second AUV survey from JC257 was undertaken 30 km south of the northern border of the UK-1 exploration area. The surveys were undertaken to derive ecological understanding on the influence of seabed topography on seabed community composition. The data were collected by scientists from the National Oceanography Centre, Southampton, UK as part of the NERC-funded Seabed Mining And Resilience To EXperimental impact (SMARTEX) project (NE/T003537/1).

The GEBCO Grid is a global terrain model for oceans and land at 30 arc-second intervals which was developed and first released in 2009 by the General Bathymetric Chart of the Oceans (GEBCO) as GEBCO 08. The current release is GEBCO 2014, released in December 2014 and updated in March 2015. GEBCO is an international group of experts who work on the development of a range of bathymetric (accurate mapping of the sea floor) data sets and data products. The bathymetric portion of the grid is largely based on a database of ship-track soundings with interpolation between soundings guided by satellite-derived gravity data. Data sets developed by other methods are also included where they improve the grid. The land portion of the grid is largely based on the US Geological Survey's SRMT30 data set, developed with data from the US National Aeronautics and Space Administration (NASA) Shuttle Radar Topographic Mission (SRTM). For the area around Antarctica, the land data are taken from the Bedmap2 data set. The grid is accompanied by a Source Identifier (SID) Grid which identifies which cells in the GEBCO Grid are based on soundings or existing grids and which have been interpolated. The data sets are updated as new bathymetric compilations are made available. Both grids are freely available to download, in netCDF; data GeoTiff and Esri ASCII raster formats, from the web. Free software is available for viewing and accessing data from the grids in netCDF and ASCII data formats. The grids are also included as part of the GEBCO Digital Atlas DVD.

This dataset is comprised of carbon isotopic composition and concentration of samples from stable isotope pulse chase tracer experiments. Data are available for sediment macrofauna, dissolved inorganic carbon in overlying water, and phospholipid fatty acids (PLFAs) in the sediment. Experiments were conducted onboard RRS James Cook (JC055) from 13/01/2011 to 22/02/2011 at three sites in the Bransfield Strait, Antarctica. Two of the sites lay on raised edifices, known as Hook Ridge and Middle Sister along the axis of the basin and included a diffuse hydrothermal site. A third site labelled as 'Off-Vent' others without hydrothermal vents was located along the north side of the basin, and was sampled as a control site. Sediment cores were recovered using a multiple corer for isotope tracing experiments. Duplicate cores were subject to two treatments; the 'algae' treatment with added algal detritus (simulating photosynthetic carbon) and the 'bicarbonate' treatment to simulate a substrate for benthic carbon fixation. Overlying water samples were analysed for concentration and isotopic composition of dissolved inorganic carbon. Frozen sediment samples were freeze dried and analysed for phospholipid fatty acids (PLFAs). Sediment horizons between 0 and 10cm preserved in formalin were sieved and macrofauna were extracted. This work was carried out by Clare Woulds, James Bell, and Louise Brown at the University of Leeds, Adrian Glover at the Natural History Museum, and Steven Bouillon at KU Leuven. It was funded by the NERC Discovery Science project Tracer Studies of Biological Carbon Cycling in Chemosynthetic Communities of the Southern Ocean (grant reference NE/J013307/1) active from March 1, 2012 to February 28, 2015.

Multibeam swath bathymetry data were collected with a hull-mounted Kongsberg EM122 echosounder during RRS James Cook cruise JC215 (Principal Investigator Helen Oldridge) in June/July 2021. The cruise was conducted to carry out geophysical equipment trials off the continental margin to the southwest of the UK. The data were edited using CARIS HIPS software by Tim Henstock and exported as generic sensor format (GSF) files for subsequent gridding by users. The data were also gridded at 100m spacing by Tim Henstock in a WGS84 Mercator projection, and were exported as longitude-latitude-depth triples. Funding was provided by the UK's Natural Environment Research Council (NERC) to National Marine Facilities (NMF) under its National Capability Large Research Infrastructure support.