Project

Investigating the effect of an earthworm-processed rock on carbon and heavy metals dynamics in grasslands

Enhanced Silicate Weathering has been proposed as a new technology to capture atmospheric carbon dioxide (CO₂) in the form of inorganic carbon (IC). This technology relies on the natural process of mineral weathering and consists on spreading very fine silicate powder on soils. Besides capturing CO₂ in the form of IC, weathering can contribute to the stabilisation of organic carbon (OC) due to the formation of new mineral surfaces. Concurrently, the weathering process can lead to the release of essential nutrients for plants’ growth, but also to heavy metals which concentrations could become toxic.

Earthworms are the most important soil ecosystem engineers and have proven to be crucial for determining soil carbon dynamics, even if their role in weathering is largely understudied. Due to their feeding on organic matter and soil particles, and to the digesting activities within their bodies, earthworms can contribute to increase organic carbon stabilisation and inorganic carbon formation through weathering by, among other mechanisms, enhancing aggregation and mineral surfaces formation.

So far, studies have focused either on the effects of the application of solely rock powder on soils or on the mechanisms through which earthworms could enhance weathering. No study has yet researched how the processing of rock powder by earthworms can be used to enhance carbon stabilisation and formation in soils, while concurrently looking at the behaviour of heavy metals.

During this MSc thesis project, you will help in conducting a greenhouse experiment where the effect of an organo-mineral mixture processed by earthworms on soil carbon and heavy metals dynamics is investigated. You will contribute to setting up a pot experiment with and without plants where the earthworm-processed rock is applied. Furthermore, you will collect soil and leachate samples to determine carbon and heavy metals content, to assess how this new earthworm-processed rock can influence carbon dynamics and heavy metals behaviour in soils. Other interests and analyses for this topic can be further discussed.