WP2.1 The Role of Microbial Decomposition in Peat Subsidence

Peatlands occupy approximately 7% of Dutch land which have been intensively used for agriculture and mining since 13th century. This led to substantial amount of peat loss and shift their carbon accumulator’s role to carbon emitters. Currently, peat loss and concomitant land subsidence threatens the ecosystem services of peatlands and the economy of the country (e.g., infrastructure damage, flood risk and salinization of groundwater) which requires an urgent, feasible and sustainable solutions. Peat loss results in land subsidence due to the known processes shrinkage, creep, consolidation and aerobic decomposition. The rates of these processes depend on groundwater level in the polders. Groundwater level determines the oxygen intrusion into the peat and thickness of the anoxic zone. Previous studies mostly focused on aerobic peat decomposition due to its relatively large contribution to land subsidence and greenhouse gas emissions. Nevertheless, some studies showed that microbial and physical processes that take place under anoxic conditions can also significantly contribute to land subsidence. Organic matter (OM) decomposition under anoxic environment might be slow and negligible for the emissions of greenhouse gasses but key for understanding land subsidence. Furthermore, interactions between physical land subsidence processes and OM decay have been neglected and might alter land subsidence predictions. Therefore, a deeper mechanistic understanding of land subsidence under oxic and anoxic conditions is necessary to have reliable subsidence models for future challenges.

My research focus in the LOSS project is to inspect the role of microbial decomposition in peat subsidence and its relationship with other subsidence processes (primary consolidation and creep). I will investigate exoenzyme activity and its interaction with phenolic compounds in the peat. Also, I will check how decomposition under oxic and anoxic conditions alters the physical characteristic of peat.

This subproject is carried out by Duygu Tolunay (UU-BIO), and supervised by dr. ir. Mariet Hefting.