A decade of interdisciplinary research on the dynamics of surface processes and landscape change at the Bonneville Salt Flats, Utah, USA

Abstract

The Bonneville Salt Flats, a landscape characterized by a perennial halite crust and seasonal flooding in western Utah, USA, provides a natural laboratory for advancing understanding of the processes that create and change dynamic saline environments. A decade of interdisciplinary research on the Bonneville Salt Flats has resulted in a new understanding of the salt's history, the functioning of the salt crust ecosystem, and the role that humans play in shaping this landscape. Sedimentological analyses of cores collected across the salt has changed our understanding of the history of the landscape, including evidence of extensive erosion after Pleistocene Lake Bonneville, the surprisingly young age of the oldest salt (~5.4 cal ka BP), and historical and ongoing crust halite dissolution. 16S rRNA gene and metagenomic analysis of the salt crust reveals a complex and robust microbial and archaeal ecosystem within the salt, hosting a wide range of metabolic pathways that actively cycle C, N, and S through the landscape. A long-term environmental observation station established at the center of the salt crust provides a robust new record of landscape processes, weather data, and eddy covariance flux measurements that have helped to constrain the energy and water budgets and highlight the sensitivity of ecosystem-scale surface conductance in the absence of vegetation to atmospheric drying. Arial and spaceborne remote sensing data show the impacts of over a century of human activities on landscape composition and texture, including groundwater extraction for potash mining, intensive surface modification, and land use associated with high-speed vehicle racing on the salt. Brine extraction and attempted mitigation have resulted in salinity and salt crust extent decreases over the last several decades, potentially limiting future landscape uses. The intricate interconnection of the human-natural system has enabled the exploration of variations in mental models influencing decision-making, attribution of blame, and the feasibility of adaptive management in dynamic landscapes serving diverse and conflicting needs. Integration of science with art has expanded the nature of the inquiry and led to new ways of thinking about human connections to a seemingly barren, but truly alive, place. All of these new insights into saline landscapes and the role that human land use and climate change play in altering processes are significant to understand as water delivered to closed basin saline lakes globally is in decline, potentially leading to an expansion of exposed salt-encrusted landscapes.