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).
