Soil Carbon Sequestration and the Role of Earthworms in an Enhanced Weathering Mesocosm Experiment

• DOI: 10.2139/ssrn.4449286
• Publication Date: 2023-05-15T21:19:32Z
• Authors: Arthur Vienne; Patrick Frings; Silvia Poblador; Laura Steinwidder; Jet Rijnders; Jonas Schoelynck; Olga Vindušková; Sara Vicca
• Keywords: Mesocosm; Carbon fibers

Virtually all scenarios that limit global warming to 1.5°C require large scale carbon dioxide removal (CDR). Enhanced Weathering (EW) is considered an attractive CDR technology because of the permanence sequestered inorganic and its scalability. Yet, a great challenge in EW research quantification weathering C sequestration rates. In addition, soil (macro)biota such as earthworms were postulated stimulate silicate dissolution both physically chemically. However, quantitative data on how influence (in)organic enhanced systems are lacking. To evaluate effect EW, we set up mesocosm experiment with following treatments: control soil, basalt, basalt earthworms.In this experiment, increased dissolved (DIC) export by only 40 kg CO2 ha-1. No significant differences organic or stocks detected short-term experiment. Nonetheless, using novel Ge/Si δ30Si monitoring found qualitative proof mineral weathering. Moreover, calculated substantial minimal rate (mWr) (>10-12 mol total alkalinity m-2 s-1) from increase exchanged base cations. Also efflux showed conisderable CDR; addition 100 ton ha-1 decreased SCE non-worm soils approximately 2 after 4.5 months. This decrease may reflect sequestration, matter stabilization have due exchangeable cations.Earthworms did not but DIC observe earthworm-induced sequestration. Instead, enlarge clay precipitation cation exchange, withholding cations system, increasing presumably stabilization. Within however, more through earthworm activity relative mesocosms, possibly indicating stimulation gut microbiota. conclusions, cause net within short experimental timeframe, yet was stimulated expected benefits for stability long run.