title: Olivine Dissolution in Seawater: Implications for CO2Sequestration through Enhanced Weathering in Coastal Environments.
abstract: Enhanced weathering of (ultra)basic silicate rocks such as 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 CO2uptake 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 CO2invasion, thus confirming viability of the basic concept of enhanced silicate weathering. However, our experiments also identified several important challenges with respect to the detailed quantification of the CO2sequestration efficiency under field conditions, which include nonstoichiometric 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 for realizing negative CO2emissions for climate mitigation purposes, these aspects need further experimental assessment.
authors.affiliation: Department of Analytical, Environmental and Geo-Chemistry, Free University of Brussels , Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: Francesc
authors.identifier: 0000-0002-9882-3376
authors.initials: F
authors.lastname: Montserrat
authors.affiliation: School of Earth and Ocean Sciences, Cardiff University , Main Building, Park Place, Cardiff, CF10 3AT United Kingdom.
authors.forename: Phil
authors.initials: P
authors.lastname: Renforth
authors.affiliation: Institute for Geology, Center for Earth System research and sustainability (CEN), Universität Hamburg , Bundesstraße 55, 20146 Hamburg, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Hartmann
authors.affiliation: Department of Analytical, Environmental and Geo-Chemistry, Free University of Brussels , Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: Martine
authors.initials: M
authors.lastname: Leermakers
authors.affiliation: Green Minerals B.V. , Boulevard 17, 6127 AX Grevenbicht, The Netherlands.
authors.forename: Pol
authors.initials: P
authors.lastname: Knops
authors.affiliation: Department of Analytical, Environmental and Geo-Chemistry, Free University of Brussels , Pleinlaan 2, 1050 Brussels, Belgium.|Aarhus Institute of Advanced Studies (AIAS), Aarhus University , Hoegh-Guldbergs Gade 6B, DK-8000 Aarhus C, Denmark.|NIOZ Royal Netherlands Institute for Sea Research, Department of Estuarine and Delta Systems, and Utrecht University , Korringaweg 7, 4401 NT Yerseke, The Netherlands.
authors.forename: Filip J R
authors.initials: FJ
authors.lastname: Meysman
mesh_terms: D002245:Carbon Dioxide; D002254:Carbonates; D012623:Seawater; D012995:Solubility; D014887:Weather
chemical_list: D002254:Carbonates; D002245:Carbon Dioxide