Climate sensitivity of the abiotic soil environment in the McMurdo Dry Valleys, Antarctica

Abstract:

The McMudro Dry Valleys (MDVs) of Antarctica are a polar desert, characterized by extremely cold and arid climatic conditions. Despite a harsh climatic setting, a vibrant microbial and inveterate soil ecosystem is present. Predicted warming in MDVs will likely facilitate enhanced landscape hydrologic connectivity, resulting in an increased abundance of perennially wet soils. It is worthwhile to understand the moisture and energy budget of perennially wet soils to develop a predictive understanding of how soil habitats may change in the future. This work aims to quantify how the abiotic soil environment in the MDVs will change under future CMIP5 climate scenarios. Specifically, we simulate ground-temperature, soil moisture, and thaw depth in four representative landscape unit models: snow-covered soil, perennially wet soil, intermittently wet soil, and dry snow-free soil. Preliminary results show that degree-days above freezing and thaw depths are greatest beneath perennially wet soils. Furthermore, perennially wet soils exhibit the greatest climate sensitivity. Overall, these results show that enhanced wetting of MDV soils will fundamentally alter the abiotic characteristics of the soil habitat, possibly promoting changes to the form and function of soil ecosystems.