Impact and recovery of pH in marine sediments subject to a temporary carbon dioxide leak. (July 2015)

• Record Type: Journal Article
• Authors: Taylor, Peter; Lichtschlag, Anna; Toberman, Matthew; Sayer, Martin D.J.; Reynolds, Andy; Sato, Toru; Stahl, Henrik
• Is Part Of: International journal of greenhouse gas control. Volume 38(2015:Jul.)
• Page Start: 93
• Page End: 101
• Publication Date: 2015-07
• Subjects: Carbon capture and storage -- Sediment pore water -- pH -- CO2; Greenhouse gases -- Environmental aspects -- Periodicals; Air -- Purification -- Technological innovations -- Periodicals; Gaz à effet de serre -- Périodiques; Gaz à effet de serre -- Réduction -- Périodiques; Air -- Purification -- Technological innovations; Greenhouse gases -- Environmental aspects; Periodicals; 363.73874605
• DOI: 10.1016/j.ijggc.2014.09.006
• Languages: English
• ISSNs: 1750-5836

Abstract

Highlights: Impact of carbon dioxide leakage on oxygen uptake and pH in surface sediments. Recovery of pH after carbon dioxide release took under 1 month. Modelling the mass of carbon dioxide remaining within the sediment after release. Abstract: A possible effect of a carbon dioxide leak from an industrial sub-sea floor storage facility, utilised for Carbon Capture and Storage, is that escaping carbon dioxide gas will dissolve in sediment pore waters and reduce their pH. To quantify the scale and duration of such an impact, a novel, field scale experiment was conducted, whereby carbon dioxide gas was injected into unconsolidated sub-sea floor sediments for a sustained period of 37 days. During this time pore water pH in shallow sediment (5 mm depth) above the leak dropped >0.8 unit, relative to a reference zone that was unaffected by the carbon dioxide. After the gas release was stopped, the pore water pH returned to normal background values within a three-week recovery period. Further, the total mass of carbon dioxide dissolved within the sediment pore fluids above the release zone was modelled by the difference in DIC between the reference and release zones. Results showed that between 14 and 63% of the carbon dioxide released during the experiment could remain in the dissolved phase within the sediment pore water.