Sediment acidification and temperature increase in an artificial CO2 vent


Contact
moritz.holtappels [ at ] awi.de

Abstract

We investigated the effect of an artificial CO2 vent (0.0015−0.037 mol s−1), simulating a leak from a reservoir for carbon capture and storage (CCS), on the sediment geochemistry. CO2 was injected 3 m deep into the seafloor at 120 m depth. With increasing mass flow an increasing number of vents were observed, distributed over an area of approximately 3 m. In situ profiling with microsensors for pH, T, O2 and ORP showed the geochemical effects are localized in a small area around the vents and highly variable. In measurements remote from the vent, the pH reached a value of 7.6 at a depth of 0.06 m. In a CO2 venting channel, pH reduced to below 5. Steep temperature profiles were indicative of a heat source inside the sediment. Elevated total alkalinity and Ca2+ levels showed calcite dissolution. Venting decreased sulfate reduction rates, but not aerobic respiration. A transport-reaction model confirmed that a large fraction of the injected CO2 is transported laterally into the sediment and that the reactions between CO2 and sediment generate enough heat to elevate the temperature significantly. A CO2 leak will have only local consequences for sediment biogeochemistry, and only a small fraction of the escaped CO2 will reach the sediment surface.



Item Type
Article
Authors
Divisions
Primary Division
Programs
Primary Topic
Helmholtz Cross Cutting Activity (2021-2027)
N/A
Peer revision
Peer-reviewed, Web of Science / Scopus
Publication Status
Published
Eprint ID
55249
DOI 10.1016/j.ijggc.2020.103244

Cite as
de Beer, D. , Lichtschlag, A. , Flohr, A. , van Erk, M. R. , Ahmerkamp, S. , Holtappels, M. , Haeckel, M. and Strong, J. (2021): Sediment acidification and temperature increase in an artificial CO2 vent , International Journal of Greenhouse Gas Control, 105 , p. 103244 . doi: 10.1016/j.ijggc.2020.103244


Download
[thumbnail of DeBeer_2021_sediment_acidification_and_temperature_increase_in_an_artificial_CO2_vent.pdf]
Preview
PDF
DeBeer_2021_sediment_acidification_and_temperature_increase_in_an_artificial_CO2_vent.pdf

Download (4MB) | Preview

Share


Citation

Geographical region

Research Platforms
N/A

Campaigns
N/A

Funded by
info:eu-repo/grantAgreement/EC/H2020/654462


Actions
Edit Item Edit Item