Is the climate change mitigation effect of enhanced silicate weathering governed by biological processes?

Abstract

A number of negative emission technologies (NETs) have been proposed to actively remove CO 2 from the atmosphere, with enhanced silicate weathering (ESW) as a relatively new NET with considerable climate change mitigation potential. Models calibrated to ESW rates in lab experiments estimate the global potential for inorganic carbon sequestration by ESW at about 0.5-5 Gt CO 2 year −1 , suggesting ESW could be an important component of the future NETs mix. In real soils, however, weathering rates may differ strongly from lab conditions. Research on natural weathering has shown that biota such as plants, microbes, and macro-invertebrates can strongly affect weathering rates, but biotic effects were excluded from most ESW lab assessments. Moreover, ESW may alter soil organic carbon sequestration and greenhouse gas emissions by influencing physicochemical and biological processes, which holds the potential to perpetuate even larger negative emissions. Here, we argue that it is likely that the climate change mitigation effect of ESW will be governed by biological processes, emphasizing the need to put these processes on the agenda of this emerging research field.

Geochemical Negative Emissions Technologies: Part I. Review

“…Specifically, it increases with increasing surface area (Strefler et al, 2018), while higher pH, lower temperature, and precipitation rates, along with varying soil CO 2 partial pressure can negatively affect the weathering rates (Verbruggen et al, 2021). Biogeochemical and biomechanical activity can also affect weathering rates in soils (Vicca et al, 2022). Plants may enhance silicate mineral weathering in soils through their roots and associated mycorrhizal fungi, via diverse mechanisms such as the release of organic acids (Taylor et al, 2009;Thorley et al, 2015;Verbruggen et al, 2021) and secretion of acids or stimulation of acid-generating nitrification by nitrogen-fixing plants (Bolan et al, 1991;Epihov et al, 2017;Perakis and Pett-Ridge, 2019).…”

“…Plants may enhance silicate mineral weathering in soils through their roots and associated mycorrhizal fungi, via diverse mechanisms such as the release of organic acids (Taylor et al, 2009;Thorley et al, 2015;Verbruggen et al, 2021) and secretion of acids or stimulation of acid-generating nitrification by nitrogen-fixing plants (Bolan et al, 1991;Epihov et al, 2017;Perakis and Pett-Ridge, 2019). Invertebrates in soil also contribute to weathering, both chemically, through the action of gut microbiota, and mechanically by biopedturbation (Van Groenigen et al, 2019;Vicca et al, 2022).…”

Biotic factors dominantly determine soil inorganic carbon stock across Tibetan alpine grasslands

“…and the production of acidity is finally neutralized through accelerating carbonate dissolution (Zamanian et al, 2016). Also, some nitrogen-fixing bacteria that lived in symbiosis with leguminous plants can acidify the soil by excreting protons during N2 fixation (Vicca et al, 2022). Furthermore, fungi are likely to accelerate carbonate neutralization by exuding protons and organic acids (Van Hees et al, 2006;Wild et al, 2021).…”

“…SIC stock and stability can be fundamentally altered by an array of abiotic and biotic processes (Raza et al, 2020). High precipitation can promote soil silicate minerals weathering and removal of base cations (Ca 2+ , Mg 2+ , K + , and Na + ) by leaching (Vicca et al, 2022). Soil acidification due to atmospheric nitrogen (N) and acid deposition and the nitrification of NH4 + may greatly accelerate soil carbonate dissolution and CO2 releases (Raza et al, 2020;Song et al, 2022).…”

Effects of Rock Powder Additions to Cattle Slurry on Ammonia and Greenhouse Gas Emissions

“…Future studies should conduct a more comprehensive macro-and micronutrient analysis of the rock powder-amended slurry, particularly to include other heavy metals and silicon (Si). Si is gaining increased agronomic attention since it can induce a broad spectrum of biotic and abiotic stress resistance in plants [66,67]. Concomitant microbiological measurements of anaerobic bacteria and of methanogens would also be interesting to gain additional insights about biogeochemical interactions.…”