Dr. Muñoz-Ortiz, Enrique

Wetlands occupy a small percentage of the Earth's surface but provide essential ecosystem services, such as water regulation, carbon cycling and habitat support. Patagonian “Vegas” are unique wetland ecosystems characterised by their groundwater recharge and hydrological dynamics, distinct from the surrounding steppe. These ecosystems play a critical role in supporting livestock with up to six times the forage productivity of the surrounding steppe and in storing over 69 g kg−1 of organic carbon. However, the influence of soil structure parameters (e.g., pore size distribution, bulk density) and soil shrinkage behaviour on soil moisture variability and ecosystem functions in Patagonian wetlands remains poorly understood. This study aimed to assess the physical capacity and intensity parameters of soils, including shrinkage properties, within a micro-watershed in southern Patagonia. Our findings reveal significant spatial variability in soil properties, with bulk density (BD) ranging from 0.12 to 1.81 Mg m−3 across topographic positions. Mineral soils on summits and footslopes exhibited high macroporosity (up to 18.1% of total pore volume at 5 cm depth), which facilitates water movement, while organic soils in the Vega centre had a higher total porosity (up to 88.8%) that enhances water and air retention. The coefficient of linear extensibility (COLE) for organic soils reached a level of 0.078, indicating a high shrinkage capacity. This shrinkage influenced the functionality of the porous system, shifting pore roles between air conduction and water storage as larger pores contracted. These dynamics, driven by climate change and increased drying cycles, may lead to significant shifts in soil functionality and ecosystem resilience. Enhanced understanding of soil physical states and their response to environmental changes can support sustainable management strategies, benefiting local agriculture and preserving these critical ecosystems.

Due to the climatic conditions in central-southern Chile, there are high heating energy consumption and PM2.5 emissions. Among the alternatives to mitigate it, the Chilean government has implemented subsidies to improve the housings envelope and to replace firewood stoves by pellet stoves and air-to-air heat pumps. Accordingly, for evaluating the effectivity of above-mentioned initiatives, this study proposes to identify the optimal solutions that minimize the energy demand, the environmental impacts, and the global costs, for social housing using different insulation materials and heating systems in four Chilean cities located in central-southern Chile. Results reveal pellet stoves with lower environmental impacts but higher global costs, while heat pumps offer an intermediate solution that can be enhanced with a greener electricity grid, but the global costs are still too high. Firewood stoves could be optimal solution depending on optimization weighting factors. The study emphasizes prioritizing housing envelope improvements in energy policies, followed by heating system enhancements. Although replacing firewood poses challenges due to costs, it is crucial for Chile’s 2050 decarbonization goal. This research provides valuable insights into the complexities and potential solutions for transitioning away from firewood in Chilean social housing.