Modeling Benthic Foraminiferal Diversity in the Arabian Gulf: Species Distribution and Environmental Controls in a Basin-Wide Assessment

Using extensive datasets of benthic foraminiferal occurrences, we investigate spatial patterns of species diversity across the Arabian Gulf and assess how environmental gradients influence these distributions through species distribution modeling approaches. We evaluate the effectiveness of stacked species distribution models in predicting foraminiferal diversity patterns and identifying potential diversity hotspots across the Arabian Gulf basin. We compiled a comprehensive dataset of benthic foraminiferal occurrences from published literature and public databases, encompassing more than 492 species from nine orders. Using an ensemble of species distribution models, we predict the spatial patterns of individual species and stack these predictions to estimate foraminiferal species richness across the basin. We validated model predictions using independent datasets and assessed the relative importance of environmental variables. Our stacked species distribution models showed high performance (mean AUC > 0.94, TSS > 0.8, Kappa > 0.82), revealing a clear north-south gradient in foraminiferal species richness. The highest diversity was observed in the northern part of the Gulf, contrasting with typical latitudinal diversity gradients. Bathymetry and dissolved oxygen emerged as primary drivers of foraminiferal distributions (10.50% and 8.55% contribution respectively), followed by iron concentration and salinity. The eastern part of the Gulf displayed higher diversity compared to the western regions, likely reflecting the influence of the counterclockwise circulation pattern. Our study provides the first basin-wide assessment of benthic foraminiferal diversity in the Arabian Gulf, revealing complex spatial patterns and environmental relationships. The models' ability to delineate species-specific niches and environmental gradients enables efficient prediction of species responses to climate-driven changes. This approach establishes a robust baseline for monitoring ecosystem shifts and offers valuable insights for both paleoenvironmental reconstructions and future targeted studies in this extreme marine environment.