Olivine dissolution in seawater: implications for CO2 sequestration through Enhanced Weathering in coastal environments

Montserrat, F., Renforth, Philip, Hartmann, J, Leermakers, M, Knops, P and Meysman, F 2017. Olivine dissolution in seawater: implications for CO2 sequestration through Enhanced Weathering in coastal environments. Environmental Science & Technology 51 (7) , pp. 3960-3972. 10.1021/acs.est.6b05942

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Abstract

Enhanced Weathering of (ultra)basic silicate rocks such olivine-rich dunite has been proposed as a large-scale climate engineering approach. When implemented in coastal environments, olivine weathering is expected to increase seawater alkalinity, thus resulting in additional CO2 uptake from the atmosphere. However, the mechanisms of marine olivine weathering and its effect on seawater carbonate chemistry remain poorly understood. Here, we present results from batch reaction experiments, in which forsteritic olivine was subjected to rotational agitation in different seawater media for periods of days to months. Olivine dissolution caused a significant increase in alkalinity of the seawater, with a consequent DIC increase due to CO2 invasion, thus confirming viability of the basic concept of enhanced silicate weathering. Yet, our experiments also identified several important challenges with respect to the detailed quantification of the CO2 sequestration efficiency under field conditions, which include non-stoichiometric dissolution, potential pore water saturation in the seabed, and the potential occurrence of secondary reactions. Before enhanced weathering of olivine in coastal environments can be considered an option to realize negative CO2 emissions for climate mitigation purposes, these aspects need further experimental assessment.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Earth and Environmental Sciences
Subjects:	G Geography. Anthropology. Recreation > GE Environmental Sciences Q Science > QE Geology
Publisher:	American Chemical Society
Date of First Compliant Deposit:	24 April 2017
Date of Acceptance:	10 March 2017
Last Modified:	22 Nov 2024 08:30
URI:	https://orca.cardiff.ac.uk/id/eprint/99134

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