This dataset consists of optical and acoustic seabed profiles of near bed hydrodynamics, bed morphology and suspended material in the water. Fieldwork was carried out by a team of researchers over a two week period, 24 May to 04 June 2013, surveying an area near Hilbre Island in the Dee Estuary. Measurements were taken in the inter-tidal and sub-tidal zones. Measurements were collected at three sites within the sampling area. A SEDbed suite of acoustic and optical instruments were deployed at each station to collect data. These instruments included CTD, LISST, Acoustic Doppler Velocimeter, Bedform and suspended sediment imager, Multi-tier sediment trap and 3-D Acoustic Rippler Profiler. The data collection described formed the fieldwork component of the NERC-funded project “Realistic Sedimentary Bedform Prediction: Incorporating Physical and Biological Cohesion (COHBED)”. The project was undertaken with the aim to produce information about the growth, movement and stability of bedforms that consist of natural mixtures of sands and muds. The project was composed of Standard Grant reference NE/I027223/1 as the lead grant with child grants NE/I026863/1, NE/I024402/1, NE/I02478X/1. The lead grant runs from 05 January 2012 to 04 July 2015 and the child grants run from 15 December 2011 to 14 June 2015 (NE/I026863/1), 01 January 2012 to 30 June 2015 (NE/I024402/1), and 01 January 2012 to 31 October 2015 (NE/I02478X/1). Dr Jacobus Hugo Baas of Bangor University, School of Ocean Sciences was the principal investigator of the lead grant of this project. The child grants were led by Dr Sarah Bass of University of Plymouth, School of Engineering, Professor Daniel Roy Parsons of University of Hull, Geography, Environment and Earth Science, and Professor Daniel Paterson of University of St Andrews, Biology, respectively. The data described here have been received as raw files by BODC and will be processed using our in-house systems and made available online in the future.

This dataset consists of geophysical and underway measurements collected on FS Meteor Cruise M115 . The cruise ran from 01 April to 28 April 2015 from Kingston, Jamaica to Pointe-a-Pitre, Guadeloupe, collecting data within the Cayman Trough. Swath bathymetry data were collected using a ship-fitted Kongsberg Simrad EM122 multi-beam deep ocean echo sounder, with data collected during the cruise along specific profiles with the aim of filling gaps in existing coverage acquired by RRS James Cook cruise JC044. A total of 170 Ocean-bottom seismograph deployments were made at various stations and depths throughout the duration of the cruise, of which 55 were National Environmental Research Council funded. Gravity data were acquired port-to-port using a Micro-G/LaCoste-Romberg air-sea gravimeter (S-40) mounted on a gyro-stabilised platform, which ran throughout the duration of the cruise. This cruise formed the field component of NERC Discovery Science project ‘Crustal accretion and transform margin evolution at ultraslow spreading rates’ which ran between March 2015 and June 2018. It’s aims were: 1) To study the structure and lithology of the crust at the Mt Dent oceanoc core complex (OCC) on the Mid‐Cayman Spreading Center (MCSC) and determine the relationship between this and the adjacent volcanic domain that also hosts hydrothermal vents and; 2) To investigate how the crust changes as it cools and ages as it spreads away from the ridge axis. The Discovery Science project was composed of Standard Grant reference NE/K011162/1. The project was funded from 23 March 2015 to 30 June 2018, and was led by Professor Christine Peirce (Durham University, Earth Sciences). Data have been received by the British Oceanographic Data Centre (BODC), archived, and are available on request from the BODC enquiries team.

This dataset consists of measurements of underway meteorology, navigation and sea surface hydrography, seismic reflection and refraction, and bathythermograph data collected during a comprehensive survey of the Tonga-Kermadec island arc-deep-sea trench system, undertaken between April and June 2011. Data were collected on RV Sonne cruise SO215 by an integrated marine geophysical experiment that comprised simultaneous seismic reflection (MCS) and wide-angle (WA) refraction, gravity, magnetic, bathymetry and sub-seabed high-resolution imaging of the Louisville Ridge-Tonga-Kermadec Trench collision system. This cruise formed the field component of NERC Discovery Science project "The Louisville Ridge-Tonga Trench collision: Implications for subduction zone dynamics". The key scientific objectives for the cruise were as follows: a)Determine the 'background' crustal and uppermost mantle structure of the subducting plate; b)Determine the crustal and uppermost mantle structure across and along the Louisville Ridge; c)Determine the physical properties of the leading edges of the subducting and over-riding plates; d)Determine the state of isostasy, ridge-related flexure and moat characteristics at the Louisville Ridge, and the mechanical properties of the subducting and over-riding plates; e)Determine the seafloor morphology and collision-related deformation in the Tonga forearc. The Discovery Science project was composed of Standard Grant reference NE/F004273/1 as the lead grant with child grant NE/F005318/1. The lead grant ran from 1 Mar 2011 - 31 Aug 2016 and the child grant ran from 1 Oct 2010 - 30 Sep 2014. Professor Christine Peirce of University of Durham, Department of Earth Sciences was the principal investigator of the lead grant of this project. Prof Anthony Watts of University of Oxford, Earth Science was the principal investigator of the child grant. The bathythermograph data have been received by BODC as raw files from the RV Sonne, processed and quality controlled using in-house BODC procedures and will be made available online soon. The remaining data have been received by BODC as raw files from the RV Sonne and are available on request.