This dataset contains visual and physical analyses of the impacts of ocean acidification on the skeletons of the cold-water coral <em>Lophelia pertusa</em>. Visual analysis includes synchrotron images from the Diamond Light Source and electron back scatter diffraction images on polished coral skeletons. Physical analyses include Raman spectroscopy data. Skeletal samples analysed were from the Southern California Bight (SCB), USA, and the Mingulay Reef Complex (MRC), UK. SCB samples were collected in 2010, 2014 and 2015. MRC samples were collected in 2012. Samples from the SCB were taken using a ROV at varying depths covering an environmental gradient with respect to aragonite saturation. Each sample represents an aggregation of <em>Lophelia pertusa</em> that was sampled with a basket attached to the ROV. The samples were transported to the surface and subsampled for live, ethanol preserved, frozen, and dried samples. Carbonate chemistry parameters of the water column were collected at the same time using a CTD and include temperature, salinity, oxygen, DIC, pH, and total alkalinity. Coral samples from the MRC were subjected to long term experimentation in projected future conditions. The conditions for MRC samples are outlined in Hennige et al. 2015. The coral samples were also analysed using a Scanning Electron Microscope (SEM) and these images are held at BODC and can be requested through this record. RAMAN spectroscopy and Electron Back Scatter Diffraction (EBSD) analysis was also used to further examine the corals under future projections of climate change. Ocean acidification is a threat to cold-water coral reefs in terms of dissolution to their skeletons, and their subsequent structural stability. This will likely determine the stability of the habitats they form. Work in the Southern California Bight was funded by the National Oceanic and Atmospheric Administration’s National Centers for Coastal Ocean Science. The study was supported by Diamond Light Source (DLS) experimental campaigns MT19794 and MT20412. This work was supported by an Independent Research Fellowship from the Natural Environment Research Council (NERC) to Sebastian Hennige (NE/K009028/1 and NE/K009028/2) and the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland), funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions. Experimental incubations for N. Atlantic corals were supported by the UK Ocean Acidification programme (NE/H017305/1 awarded to John Murray Roberts). Imaging analysis by Uwe Wolfram and Alexander Groetsch were supported by Engineering and Physical Sciences Research Council (EPSRC) of the UK under grant number EP/P005756/1.

Dataset was collated from surveys in the west side of Vavvaru Island, Lhaviyani Atoll, Maldives. The data were collected as a series of triplicate 25 m x 2 m transecs parallel to shore, at three locations on the reef flat: near (70 m from the shore), mid (140 m from the shore) and far (210 m from the shore). All locations were at similar depths of 1 m. This took place during March 2015. Along each transect the number and size of all coralliths and total number of non-free living individuals were recorded, alongside with several environmental parameters (Water Temperature, Photosynthetically Available Radiation (PAR), Total Alkalinity, Dissolved Inorganic Carbon and Dissolved Oxygen). Abundance and size of coralliths was recorded through non-invasive techniques and the environmental parameters were obtained through multiple instruments: Fluorometer, Oxygen sensor, spectrophotometry, Titration and a PAR logger. The aim was to examine whether corals have the capacity to create their own stable habitat through 'free-living stabilisation'. The work was supported by an Independent Research Fellowship from NERC to Sebastian Hennige (NE/K009028/1; NE/K009028/2), an Independent Research Fellowship from the Marine Alliance for Science & Technology for Scotland to Heidi Burnett, an Independent Research Fellowship from the Royal Society of Edinburgh / Scottish Government (RSE 48701/1) and NERC (NE/H010025) to Nick Kamenos, a Gilchrist Fieldwork Award to Heidi Burnett, Sebastian Hennige and Nick Kamenos by the Gilchrist Educational Trust, administered by the Royal Geographical Society (with the Institute of British Geographers), and a Research Incentive Grant from the Carnegie Trust for the Universities of Scotland to Heidi Burnett, Sebastian Hennige and Nick Kamenos (grant # 70013). Field sampling was under permission from the Maldives Ministry of Fisheries and Agriculture ((OTHR) 30-D/lNDIV/2015).

The Scottish Environment Protection Agency (SEPA) Marine National Environmental Monitoring Buoy Network provides real time, high frequency environmental data from strategic locations around the Scottish coast, as part of SEPA obligations to monitor the marine environment. The monitoring buoy network has been in place in some places from as early as 1996 with more buoys being deployed for ongoing measurements of the marine environment. Continuous monitoring equipment gathers dissolved oxygen, water temperature, salinity and chlorophyll-a data at regular intervals. The data is stored internally and downloaded at regular maintenance intervals. Data is collected by SEPA from monitoring buoys, mostly every 15 minutes. The data was submitted to the British Oceanographic Data Centre (BODC) for "data banking." Data has been removed as part of the SEPA quality control procedure leading to periods of absent data. This also occurs through power failure or lack of deployment. Further quality control by BODC will flag suspect data. The data is used to assess the state of the marine environment at representative locations. Salinity is used to indicate changes in water masses. Salinity decreases as freshwater inputs increase and oxygen is more soluble in freshwater than seawater. Water temperature is closely linked to seasonal changes and oxygen becomes less soluble as the water temperature increases. Chlorophyll-a is an indicator of the biomass of phytoplankton. Phytoplankton blooms are common occurrences at the start and end of the growing season in spring and autumn however excessive phytoplankton is indicated by enhanced abundance throughout the growing season (90 percentile concentration >15 µg/l measured from April to September). Excessive phytoplankton growth may cause an undesirable disturbance to the ecosystem if the decaying algae remove oxygen from the water column and sea bed as a result of microbial breakdown. Dissolved oxygen is one of the most important indicators of the health of a water body and high levels are needed to support a variety of marine life. Dissolved oxygen concentrations are affected by salinity, temperature and phytoplankton growth. Dissolved oxygen produced by photosynthesis may result in supersaturation (>100%) during the growing season. Dissolved oxygen is removed by the microbial breakdown of organic matter.

The RAPID-AMOC (Rapid Climate Change - Atlantic Meridional Overturning Circulation) data set consists of pressure, current velocities, temperature, salinity, density, oxygen, alkalinity, pH, PCO2 and inorganic carbon time series. Measurements are collected by moored instruments deployed in arrays across the Atlantic at approximately 26.5N for the Monitoring the Atlantic Meridional Overturning Circulation at 26.5N (MOC) project and the Atlantic BiogeoChemical Fluxes (ABC Fluxes) project. The data set also consists of conductivity- temperature-depth (CTD) profiles, and ships' underway monitoring system meteorology and surface hydrography collected during the mooring deployment and servicing cruises. The RAPID-AMOC data set follows on from the original Rapid Climate Change (RAPID) Programme oceanographic dataset and the RAPID-WATCH dataset. It spans data collected from 2015 to the present and is intended to continue to collect data until approximately 2020. The main aims of the RAPID-AMOC Programme are to provide oceanographic measurements that continue the long time series of the Atlantic Meridional Overturning Circulation to be derived for use in climate change research. The MOC and ABC Fluxes projects are led by scientists at the National Oceanography Centre in Southampton.

The data set includes the classical oceanographic parameters of temperature, salinity, nutrients, oxygen, pH, alkalinity, and chlorophyll-a. This data set comprises more than 100,000 profiles collected by UK research and naval vessels in the shelf seas around the UK, the North Atlantic, the Norwegian Sea, the Barents Sea, the Mediterranean Sea, the South Atlantic, the Southern Oceans, the Indian Ocean, the Arabian Sea, the East Indian Archipelago (Indonesia) and the Pacific Ocean since the beginning of the twentieth century. In recent years, conductivity-temperature-depth (CTD) data have been collected in a higher resolution form than water bottle data; these have been included in this data set in a reduced resolution/water bottle form and merged with any available chemical parameters. This data set is one of the most complete of its kind in the world; the majority of the data known to have been collected prior to 1970 have been 'rescued' and work will continue to rescue the remainder. All of the profiles in this data set have been quality checked, cross-checked against original documentation, and all duplications removed. This data set has been compiled by the International Council for the Exploration of the Sea (ICES) Oceanographic Data Centre and is available from the ICES website.

The RAPID-AMOC (Rapid Climate Change - Atlantic Meridional Overturning Circulation) data set consists of pressure, current velocities, temperature, salinity, density, oxygen, alkalinity, pH, PCO2 and inorganic carbon time series. Measurements are collected by moored instruments deployed in arrays across the Atlantic at approximately 26.5N for the Monitoring the Atlantic Meridional Overturning Circulation at 26.5N (MOC) project and the Atlantic BiogeoChemical Fluxes (ABC Fluxes) project. The data set also consists of conductivity- temperature-depth (CTD) profiles, and ships' underway monitoring system meteorology and surface hydrography collected during the mooring deployment and servicing cruises. The RAPID-AMOC data set follows on from the original Rapid Climate Change (RAPID) Programme oceanographic dataset and the RAPID-WATCH dataset. It spans data collected from 2015 to the present and is intended to continue to collect data until approximately 2020. The main aims of the RAPID-AMOC Programme are to provide oceanographic measurements that continue the long time series of the Atlantic Meridional Overturning Circulation to be derived for use in climate change research. The MOC and ABC Fluxes projects are led by scientists at the National Oceanography Centre in Southampton.

The cross-disciplinary themes will result in a diverse data catalogue. The ship collected data will be in the form of sea surface meteorology (2-D wind speed and direction, total irradiance, Photosynthetically Active Radiation/PAR, air temperature, atmospheric pressure, humidity); atmospheric carbon dioxide (pCO2); biological, chemical and physical properties and processes in the marine photic zone (carbonate chemistry - pCO2, total alkalinity, pH, DIC; dissolved gases - oxygen; nutrient concentrations, ammonium regeneration, nitrification, nitrogen fixation, zooplankon ecology, chlorophyll concentration, photosynthetic pigment composition, bacterial production, phytoplankton and bacterial speciation, concentrations of biogenic trace compounds such as dimethyl sulphide/DMS and dimthylsulphoniopropionate/DMSP, salinity, temperature, zooplankon ecology) and bioassays of these same parameters under different future IPCC CO2 and temperature scenarios. The long-term (18 month) laboratory based mesocosm experiments will include data on individual organism response (growth, immune response, reproductive fitness) under different future IPCC CO2 and temperature scenarios in rocky intertidal, soft sediment and calcareous biogenic habitats, as well as the effects on commercially important species of fish and shellfish. The analysis of sediment cores will provide greater resolution of the paleo record during the Paleocene-Eocene Thermal Maximum (PETM). Data will be used to aid the parameterisation of coastal and continental shelf seas (Northern Europe and the Arctic) model runs as well as larger scale global models. The shipboard fieldwork will take place around the UK, in the Arctic Ocean and the Southern Ocean. The mesocosms will look at temperate marine species common to UK shelf seas. Sediment cores have been collected from Tanzania. The models will look from the coastal seas of Northern Europe to the whole globe. Data to be generated will include data collected at sea, short-term (2-3 day) ship-board bioassays, from long-term (18 month) laboratory based mesocosm experiments and reconstructed paleo records from sediment cores. The 5 year UK Ocean Acidification Research Programme is the UK’s response to growing concerns over ocean acidification. Aims: 1 - to reduce uncertainties in predictions of carbonate chemistry changes and their effects on marine biogeochemistry, ecosystems and other components of the Earth System; 2 - to understand the responses to ocean acidification, and other climate change related stressors, by marine organisms, biodiversity and ecosystems and to improve understanding of their resistance or susceptibility to acidification; 3 - to provide data and effective advice to policy makers and managers of marine bioresources on the potential size and timescale of risks, to allow for development of appropriate mitigation and adaptation strategies. The study unites over 100 marine scientists from 27 institutions across the UK. It is jointly funded by Department for Environment, Food and Rural Affairs (Defra), the Natural Environment Research Council (NERC) and Department of Energy and Climate Change (DECC).

This dataset contains derived annual mean globally averaged variables from an existing global coupled carbon-climate Earth System Model and a novel atmosphere-ocean box model to understand surface warming response in terms of changes in global carbon inventories, empirical heat budget, and variation in time with carbon emissions. The source model outputs were generated by Thomas Froelicher in 2015 using a 1000-year simulation of the global coupled carbon-climate Earth System Model developed at the Geophysical Fluid Dynamics Laboratory (GFDL ESM2M). A scenario was forced of a 1% annual rate increase in carbon dioxide from preindustrial levels until global mean surface air temperature increased by 2 degrees Celsius since the preindustrial, after this point emissions of carbon were set to zero and all other non-carbon dioxide greenhouse gases were kept at preindustrial levels. Output parameters included: ocean temperature; salinity; dissolved inorganic carbon; ocean alkalinity; dissolved inorganic phosphate; surface air temperature; atmospheric carbon dioxide and cumulative carbon emission. Annual mean variables were then derived from these data. This was determined by calculated changes in: ocean carbon inventory; ocean carbon under saturation; saturated dissolved inorganic carbon; ocean dissolved inorganic carbon; radiative forcing from carbon dioxide; and ocean heat uptake. Additionally the dependence of radiative forcing on carbon emissions, dependence of surface warming on radiative forcing and surface warming dependence on radiative forcing were determined. The box model consists of three homogeneous layers: a well‐mixed atmosphere; an ocean mixed layer with 100‐m thickness; and an ocean interior with 3,900‐m thickness, all assumed to have the same horizontal area. The model solves for the heat and carbon exchange between these layers, including physical and chemical transfers, however ignoring biological transfers, and sediment and weathering interactions. The model is forced from an equilibrium by carbon emitted into the atmosphere with a constant rate of 20 PgC/year for 100 years and integrated for 1,000 years. Ocean ventilation is represented by the ocean interior taking up the heat and carbon properties of the mixed layer on an e-folding time scale of 200 years. These datasets were generated as part of the Natural Environment Research Council (NERC) Discovery Science project “Mechanistic controls of surface warming by ocean heat and carbon uptake” standard grant reference NE/N009789/1 lead by Principal Investigator - Professor Ric Williams, University of Liverpool and Co-Investigator - Dr Philip Goodwin, University of Southampton. Data are acrvhived at the British Oceanographic Data Centre.

Within Pacific Small Island Developing States (Pacific SIDS), the ridge-to-reef (R2R) approach has emerged as a framework for monitoring river connectivity between terrestrial and marine ecosystems. The study measured water quality, including pH and a range of othe physical and chemical properties over 88.40 km of the Ba River in Fiji. The sampling design focused on measuring spatio-temporal variability in pH throughout the sugarcane season (April - August) with three rapid sampling periods (RSP1, 2 & 3) along the Ba River, together with continuous measurement of temperature and pH using stationary data loggers at two locations upstream and downstream of the sugar mill (April to August 2019). Spatial variability in pH and water quality was characterized before (RSP1 and RSP2) and during (RSP3) the sugarcane season. Mean pH measured before the sugarcane crushing season for RSP1 and RSP2 were 8.16 (± 0.49) and 8.20 (± 0.61) respectively. During the sugarcane crushing season (RSP3) mean pH declined by 3.06 units to 6.94 within 42 m downstream of the sugar mill (P < 0.001). The 3.06 unit decline in pH for RSP3 exceeded both the mean diurnal variation in pH of 0.39 and mean seasonal variation in pH of 2.01. This decline in pH could be a potential source of acidification to downstream coastal ecosystems with implications for coral reefs, biodiversity and fishery livelihoods.

The Catlin Arctic Survey created a unique collaboration between scientists and explorers to undertake field research in the Arctic. Each Catlin Survey comprised of two principle parts. The 'Catlin Ice Base', which was a stationary scientific research base located off the northern coast of Canada; and the 'Explorer Team', comprising of a small long-range specialist team moving on foot from close to the North Geographic Pole towards Greenland. The Catlin Ice Base consisted of temporary polar shelters and tents erected on the sea ice off the coast of Ellef Ringnes Island, Nunavut, Canada, 78°46'27" N / 104°42'49" W. In 2010 and 2011 during the second and third Catlin Arctic Surveys, scientists and explorers examined the upper layers of the Arctic Ocean's water column. In parallel, scientists from the US, UK and Canada conducted experiments at a unique research station on the frozen Arctic Ocean with the support of experienced polar explorers and guides. These datasets (as .xls and .csv files) resulted from the work carried out at the Ice Base. Here a group, of up to 10 scientists and operational staff, were able to collect and analyze samples from under the sea ice as well as deploy heavier instrumentation up to a depth of 200 metres. Scientists at the ice base made measurements of temperature, salinity, total alkalinity, DIC, nutrients, chlorophyll, zooplankton community structure and physiological responses to elevated pCO2 levels. The Catlin Arctic Survey has enabled the monitoring, measuring and collection of information to improve scientific understanding of the processes involved in, and the impacts of, climate change. The scientists researched how changes within the seawater beneath the floating sea ice may be affecting powerful ocean currents that influence prevailing climate and weather patterns worldwide. These data were collected as part of the Catlin Arctic Survey funded by Catlin Ltd. and coordinated by Geo Mission Ltd. Participants were supported by a Natural Environment Research Council (NERC) UK Fellowship, PML Lord Kingsland Fellowship, Ralph Brown Expedition Grant from the Royal Geographical Society, NERC's National Centre for Earth Observation, World Wildlife Fund for Nature and Fisheries and Oceans Canada.