Transformations in a hypersaline lake: Examining the linkages between water level changes and Aeolian dust generation

The decline of hypersaline lakes, such as Maharloo Lake, presents significant ecological challenges. That highlights the need to comprehensively analyze the changing dynamics driven by human activities and climate change. Satellite imagery analysis from 1987 to 2022 reveals that the surface area of Maharloo Lake has decreased from 270 to 252 square kilometers due to land use changes. Moreover, the water level of the lake has declined by 30% during the wet season (May) and 90.2% during the dry season (October). The primary factors contributing to this decline include changes in temperature, potential evapotranspiration, excessive groundwater extraction, and the diversion of surface water for agriculture and urban development. These changes have transformed Maharloo Lake from a permanent to a seasonal lake, leading to an increase in the overall extent of barren, saline lands. The lake sediments are predominantly composed of fine-grained, destructive deposits with chemical salts, with over 90% being silt and clay. The average maximum wind speed and threshold erosion velocity indicate a reduced role of wind in eroding the lake's surface sediments, and the low levels of fine particulate matter (PM_2.5) and Total Suspended Particulates (TSP) particles around the lake suggest the sediments are resistant to wind erosion and have not been a significant source of dust storms thus far. Understanding the nature of the sediments and their sensitivity to wind erosion, as well as the influence of the erosive wind factor in the occurrence of dust storms, is crucial. One cannot uniformly consider all lakes or dried lake beds as sources of dust storms based solely on changes in water levels.