Negative emission technologies target the removal of carbon dioxide (CO2) from the atmosphere, and are being actively investigated as a strategy to limit global warming to within a 2°C increase. Enhanced silicate weathering (ESW) is an approach that uses the natural process of silicate weathering for the removal of CO2 from the atmosphere. The geochemical basis is firmly established: during dissolution of silicate minerals in seawater, CO2 is consumed and sequestered into the ocean. Hence, by deliberately introducing fast-weathering silicate minerals into the coastal zone, one could create a coastal CO2 sink. A principal advantage of ESW over other negative emission technologies is that it also counteracts ocean acidification and that it can be directly integrated into existing coastal management programs with existing technology. Although model studies show its feasibility, there has been no rigorous assessment of its CO2-sequestration efficiency and environmental impacts, which are bottlenecks to its commercial implementation. In this project, we will conduct a set of large-scale experiments to investigate the rate of ESW and associated CO2 uptake under realistic natural settings (bioturbation, waves, currents) as well as potentially important influences on the biogeochemical cycling in coastal ecosystems (release of trace metals, alkalinity and dissolved silicate).