Quantification of a subsea CO2 release with lab-on-chip sensors measuring benthic gradients

Schaap, A, Koopmans, D, Holtappels, M, Dewar, M, Arundell, M, Papadimitriou, S, Hanz, R, Monk, S, Mowlem, M and Loucaides, S 2021 Quantification of a subsea CO2 release with lab-on-chip sensors measuring benthic gradients. International Journal of Greenhouse Gas Control, 110. 103427. https://doi.org/10.1016/j.ijggc.2021.103427

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Official URL: http://dx.doi.org/10.1016/j.ijggc.2021.103427


We present a novel approach to detecting and quantifying a subsea release of CO2 from within North Sea sed�iments, which mimicked a leak from a subsea CO2 reservoir. Autonomous lab-on-chip sensors performed in situ measurements of pH at two heights above the seafloor. During the 11 day experiment the rate of CO2 release was gradually increased. Whenever the currents carried the CO2-enriched water towards the sensors, the sensors measured a decrease in pH, with a strong vertical gradient within a metre of the seafloor. At the highest release rate, a decrease of over 0.6 pH units was observed 17 cm above the seafloor compared to background mea�surements. The sensor data was combined with hydrodynamic measurements to quantify the amount of CO2 escaping the sediments using an advective mass transport model. On average, we directly detected 43 ± 8% of the released CO2 in the water column. Accounting for the incomplete carbonate equilibration process increases this estimate to up to 61 ± 10%. This technique can provide long-term in situ monitoring of offshore CO2 res�ervoirs and hence provides a tool to support climate change mitigation activities. It could also be applied to characterising plumes and quantifying other natural or anthropogenic fluxes of dissolved solutes.

Item Type: Publication - Article
Additional Keywords: Carbon capture and storage Reservoir monitoring Autonomous sensors Benthic gradients Plume quantification
Divisions: Plymouth Marine Laboratory > Science Areas > Marine System Modelling
Depositing User: S Hawkins
Date made live: 29 Mar 2023 11:08
Last Modified: 13 Dec 2023 12:21
URI: https://plymsea.ac.uk/id/eprint/9903

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