CAS Proposes New Ecological Modeling Method to Predict Groundwater Solute Distribution

Researchers at the Northeast Institute of Geography and Agricultural Ecology of the Chinese Academy of Sciences, along with collaborators from Henan University, have proposed a new paradigm for groundwater research that integrates ecological modeling concepts. This approach is particularly relevant for accurately simulating the distribution of solutes in shallow groundwater, which plays a crucial role in soil salinization and can trigger widespread ecological impacts, threatening land productivity and biodiversity, and affecting human living conditions. Shallow groundwater solute transport is a complex issue due to the intricate hydraulic connections, uneven spatial distribution, and diverse influencing factors of these systems. Additionally, the scarcity of field observation data in arid regions makes precise simulation of solute concentrations particularly challenging. To address this, the research team applied Species Distribution Models (SDMs), commonly used in ecology to predict species' habitats, to forecast the spatial distribution of key solutes such as Na+, K+, SO4²-, and Cl- in shallow groundwater. By combining traditional hydrological models with machine learning techniques, the team developed a large-scale simulation model for solute distribution in arid regions. This model integrates a multidimensional database that includes topography, climate, hydraulic interactions, soil properties, and human activities. The researchers analogized solute concentrations to "niches" in ecological systems, using SDMs to simulate their spatial patterns in groundwater. To overcome the limitations of sparse field data, the study employed advanced algorithms such as endmember mixture analysis, random forests, and AICc model selection. These methods improved prediction accuracy by over 30% compared to traditional spatial interpolation techniques. The findings revealed that the concentrations of Na+, K+, SO4²-, and Cl- in shallow groundwater are primarily regulated by surface water chemistry, while Ca²+ distribution is linked to deep groundwater. Human activities, especially in agricultural irrigation areas, showed a strong positive correlation with solute concentrations. Among climate factors, precipitation and evaporation were found to significantly influence solute transport. This innovative approach provides a fresh perspective on the mechanisms of solute migration in shallow groundwater and offers a technological means to precisely identify saline accumulation zones and manage groundwater resources scientifically. The research has been published online in Water Resources Research and was supported by the National Natural Science Foundation of China and the Special Fund for Black Soil Granary Technology War, among others. The integration of ecological modeling with groundwater studies not only enhances our understanding of environmental processes but also serves as a valuable tool for conservation and resource management. This interdisciplinary method could pave the way for more accurate and effective strategies in mitigating the adverse effects of soil salinization and ensuring the sustainability of groundwater resources.