The potential for leakage of CO2 from a storage reservoir into the overlying marine sediments and into the water column and the impacts on benthic ecosystems are major challenges associated with Carbon Capture and Storage (CCS) in subseafloor reservoirs. A field-scale controlled CO2 release experiment was conducted in shallow, unconsolidated marine sediments. Changes were monitored of the chemical composition of the sediments and overlying water column before, during and up to 1 year after the 37-day long CO2 release from May 2012 to May 2013 in Ardmucknish Bay. Meiofaunal samples were collected and meiofauna higher taxa and the nematodes species (where possible) were identified by Plymouth Marine Laboratory. This dataset was collected under the program QICS (Quantifying and monitoring environmental impacts of geological carbon storage) which was funded by the Natural Environment Research Council (NERC), with support from the Scottish Government. The results are contained in an Excel file. QICS project website: www.bgs.ac.uk/qics/home.html. This data is currently under embargo until publication of the dataset in research article (estimated end of 2015).

The response of the benthic microbial community to a controlled sub-seabed CO2 leak was assessed using quantitative PCR measurements of benthic bacterial, archaeal and cyanobacteria/chloroplast 16S rRNA genes. Similarly, the impact of CO2 release on the abundance of benthic bacterial and archaeal ammonia amoA genes and transcripts, and also to the abundance of nitrite oxidizer (nirS) and anammox hydrazine oxidoreductase (hzo) genes and transcripts. Samples were taken from four zones (epicentre (zone 1); 25m distant (zone 2), 75m distant (zone 3) and 450m distant (zone 4)) during 6 time points (7 days before CO2 exposure, after 14 and 36 days of CO2 release, and 6, 20 and 90 days after the CO2 release had ended). Changes to the active community of microphytobenthos and bacteria were also assessed before, during and after CO2 release using Denaturing Gradient Gel Electrophoresis of cyanobacteria/chloroplast 16S rRNA. Changes to the composition of the active bacterial community was assessed first using Terminal Restriction Fragment Length Polymorphism (T-RFLP) of bacterial 16S rRNA. In depth comparisons of possible changes to the active bacterial community at zone 1 and 4 before, during and immediately after the CO2 release was performed using 16S rRNA 454 pyrosequencing. This dataset was created by Plymouth Marine Laboratory (PML) under the program QICS (Quantifying and monitoring environmental impacts of geological carbon storage) which was funded by the Natural Environment Research Council (NERC), with support from the Scottish Government. The results are contained in three text files. QICS project website: www.bgs.ac.uk/qics/home.html. Tait et al. (2015) Rapid response of the active microbial community to CO2 exposure from a controlled sub-seabed CO2 leak in Ardmucknish Bay (Oban, Scotland). IJGGC DOI: 10.1016/ijggc.2014.11.021. Watanabe et al. (2015) Ammonia oxidation activity of microorganisms in surface sediment to a controlled sub-seabed release of CO2. IJGGC DOI: 10.1016/j.ijggc.2014.11.013.

This dataset contains data from a marine geophysical and multibeam survey which took place in April 2012 in the area of Ardmucknish Bay on board the RV White Ribbon. This was a follow up survey to the previous work carried out in this area in 2011 (2011/4). QICS (Quantifying and monitoring potential ecosystem impacts of geological carbon storage) was a scientific research project funded by NERC; its purpose was to improve the understanding of the sensitivities of the UK marine environment to a potential leak from a carbon capture storage (CCS) system. The aim of the survey was to assess any affect the drilling of the borehole had on the underlying sediments. Sea floor bathymetry data were collected using a Kongsberg EM3002D multibeam system. Sub bottom seismic profiling data were collected using an Applied Acoustics surface tow boomer (STB). Technical details of the survey are contained in the BGS Report of Survey. Webpage www.bgs.ac.uk/QICS/. NERC Grant NE/H013954/1.

CO2 was injected into shallow unconsolidated marine sediments in Ardmucknish Bay, Oban. 2D seismic reflection data were collected pre-release (15/05/2012), syn-release (17/05/2012, 18/05/2012, 19/052012, 29/05/2012, 30/05/2012, 20/06/2012) and after release stages (23/04/2014 and 24/04/2014) of CO2 help to better understand the spatial and temporal evolution of free gas anomalies within the overburden. The impact of CO2 on sediment acoustic properties, namely seismic reflectivity and attenuation, was also investigated. This dataset was collected by the National Oceanography Centre Southampton (NOCS) and the British Geological Survey (BGS) under the program QICS (Quantifying and monitoring environmental impacts of geological carbon storage) which was funded by the Natural Environment Research Council (NERC), with support from the Scottish Government. The dataset includes segy files, a presentation which summarises the main results and a map showing the spatial extent of the seismic data collected after gas release. QICS project website: http://www.bgs.ac.uk/qics/home.html. Cevatoglu et al., 2015. Gas migration pathways, controlling mechanisms and changes in sediment acoustic properties observed in a controlled sub-seabed CO2 release experiment. Int J Greenhouse Gas Control. DOI:10.1016/j.ijggc.2015.03.005. NERC grant NE/H013873/1

This dataset contains data from a marine multibeam and geophysical survey which took place in June 2011 in the Ardmucknish Bay area on board the BGS survey vessel RV White Ribbon. The survey was carried out by the British Geological Survey (BGS) in collaboration with Scottish Association for Marine Science (SAMS) and National Oceanography Centre (SAMS). QICS (Quantifying and monitoring potential ecosystem impacts of geological carbon storage) was a scientific research project funded by NERC. The purpose was to collect the data necessary to identify a potential directional drilling route from shore to a submerged gas release point. Sea floor bathymetry data were collected using an EM3002D. Sub bottom seismic profiling data were collected using a surface tow boomer. Technical details of the survey are contained in the BGS Report of Survey. Webpage www.bgs.ac.uk/QICS/. NERC Grant. NE/H013962/1.

This dataset contains data from a marine geophysical survey which took place on 1st October 2014 in the area of Ardmucknish Bay on board the RV White Ribbon. The survey was carried out by the British Geological Survey (BGS). This was a follow up survey to the previous work carried out in this area (Surveys: 2011/4 and 2012/5, 2012/7) to monitor changes in the geometry of gas charged sediments. QICS (Quantifying and monitoring potential ecosystem impacts of geological carbon storage) was a scientific research project funded by NERC; its purpose was to improve the understanding of the sensitivities of the UK marine environment to a potential leak from a carbon capture storage (CCS) system. Sub bottom seismic profiling data were collected using an Applied Acoustics surface tow boomer (STB). Webpage www.bgs.ac.uk/QICS/.

This dataset contains data from a marine geophysical and multibeam survey took place in June 2012 in the area of Ardmucknish Bay on board the RV White Ribbon. This was a follow up survey to the previous work carried out in this area (2011/4 and 2012/5). QICS (Quantifying and monitoring potential ecosystem impacts of geological carbon storage) was a scientific research project funded by NERC; its purpose was to improve the understanding of the sensitivities of the UK marine environment to a potential leak from a carbon capture storage (CCS) system. Sea floor bathymetry data were collected using a Kongsberg EM3002D multibeam system. Sub bottom seismic profiling data were collected using an Applied Acoustics surface tow boomer (STB). Webpage www.bgs.ac.uk/QICS/. NERC grant NE/H013954/1.

CO2 was injected into shallow unconsolidated marine sediments in Ardmucknish Bay, Oban. 2D seismic reflection data were collected pre-release (15/05/2012), syn-release (17/05/2012, 18/05/2012, 19/052012, 29/05/2012, 30/05/2012, 20/06/2012) and after release stages (23/04/2014 and 24/04/2014) of CO2 help to better understand the spatial and temporal evolution of free gas anomalies within the overburden. The impact of CO2 on sediment acoustic properties, namely seismic reflectivity and attenuation, was also investigated. This dataset was collected by the National Oceanography Centre Southampton (NOCS) and the British Geological Survey (BGS) under the program QICS (Quantifying and monitoring environmental impacts of geological carbon storage) which was funded by the Natural Environment Research Council (NERC), with support from the Scottish Government. The dataset includes segy files, a presentation which summarises the main results and a map showing the spatial extent of the seismic data collected after gas release. QICS project website: http://www.bgs.ac.uk/qics/home.html. Cevatoglu et al., 2015. Gas migration pathways, controlling mechanisms and changes in sediment acoustic properties observed in a controlled sub-seabed CO2 release experiment. Int J Greenhouse Gas Control. DOI:10.1016/j.ijggc.2015.03.005. The post-release data is currently restricted. NERC grant NE/H013873/1

The potential for leakage of CO2 from a storage reservoir into the overlying marine sediments and into the water column and the impacts on benthic ecosystems are major challenges The potential for leakage of CO2 from a storage reservoir into the overlying marine sediments and into the water column and the impacts on benthic ecosystems are major challenges associated with Carbon Capture and Storage (CCS) in subseafloor reservoirs. To investigate the consequences of CO2 leakage for the marine environment, a field-scale controlled CO2 release experiment was conducted in shallow, unconsolidated marine sediments. Changes of the chemical composition of the sediments, their pore waters and overlying water column were monitored before, during and up to 1 year after the 37-day long CO2 release from May 2012 to May 2013. In particular this focused on changes in the solid phase (physical properties, major and minor elemental composition, inorganic and organic carbon content), the pore water chemical composition (cations, anions, nutrients and the carbonate system parameters total alkalinity, dissolved inorganic carbon and isotopic signature of DIC) and the water column chemical composition (oxygen, nutrients, total alkalinity and dissolved inorganic carbon). This dataset was collected by the National Oceanography Centre (NOC) under the program QICS (Quantifying and monitoring environmental impacts of geological carbon storage) which was funded by the Natural Environment Research Council (NERC), with support from the Scottish Government. The results are contained in an Excel file. QICS project website: www.bgs.ac.uk/qics/home.html. Lichtschlag et al. (2014) Effect of a controlled sub-seabed release of CO2 on the biogeochemistry of shallow marine sediments, their pore waters, and the overlying water column, http://www.sciencedirect.com/science/article/pii/S1750583614003090 (doi:10.1016/j.ijggc.2014.10.008).

QICS (Quantifying and monitoring environmental impacts of geological carbon storage) was a program funded by the Natural Environment Research Council (NERC), with support from the Scottish Government (May 2010 - December 2014) with two objectives. Firstly, to assess if any significant environmental impact would arise, if a leak from sub-sea, deep geological storage of carbon dioxide occurred. Secondly, to test and recommend tools and strategies for monitoring for (or assuring the absence of) leakage at the sea floor and in overlying waters. This data set provides a short overview of the novel experimental procedure - a world first leakage simulation in the natural environment and describes the experimental set up, sampling strategy including both temporal and spatial details. The data set consists of a pdf containing a text based project and experimental overview, a table outlining the temporal evolution of the experiment, including site selection, set up, baseline, impact and recovery phases and a diagram outlining the spatial sampling strategy. This data set contains an overview document collated by Plymouth Marine Laboratory. This provides the context for a number of specific related QICS datasets submitted to the UKCCS data archive, covering a range of geological, chemical and ecological information. QICS project website: www.bgs.ac.uk/qics/home.html. Blackford et al., 2014. Detection and impacts of leakage from sub-seafloor deep geological carbon dioxide storage. Nature Climate Change 4, 1011-1016. DOI: 10.1038/NCLIMATE2381. Taylor et al., 2015. A novel sub-seabed CO2 release experiment informing monitoring and impact assessment for geological carbon storage. Int J Greenhouse Gas Control. DOI:10.1016/j.ijggc.2014.09.007.