Experimental verification of the influence of biota on enhanced silicate weathering.

At the 2015 climate summit in Paris, the world committed to limit warming to well below 2°C. Besides rapid and complete decarbonization of all sectors, achieving these targets will require deployment of negative emission technologies (NETs), which actively remove CO2 from the atmosphere and ensure long-term sequestration. Various techniques have been proposed, including several land-based solutions that involve the use of natural processes. However, no technique is yet available at scale and the lack of empirical data currently hampers development of realistic roadmaps for the necessary rapid, safe and large-scale deployment of NETs. A promising but yet poorly studied land-based NET is enhanced silicate weathering (EW). Thus far, research on the C sequestration potential of EW has been limited mostly to lab column experiments, which do not include soil and important biota and are thus still far from reality. Biota such as plants, mycorrhizal fungi and earthworms can be critical determinants of mineral weathering, but their influence on EW remains to be verified. On the other hand, field investigations face a major challenge because weathering products and hence C sequestration rates are very difficult to accurately quantify. This is especially due to the difficulty in determining leaching losses. The current project therefore envisions a crucial research step between the lab-based experiments and future applied large field-scale applications: mesocosm experiments which include important biota and at the same time allow for accurate quantification of weathering products and hence C sequestration rates. These mesocosm experiments will specifically test for the influence of important biota – plants, mycorrhizal fungi and earthworms – hence providing important information needed to extrapolate lab-based results to the real world.

Keywords:CARBON SEQUESTRATION, CLIMATE MITIGATION

Disciplines:Biogeochemistry, Soil ecology, Sustainable agriculture