Temporal, Spatial, and Environmental Variation in Virus-like Particle Abundance in the Northwestern Arabian Gulf.

Marine viruses are important components of microbial communities and influence their structure and dynamics, yet their variability remains poorly documented in the northwestern Arabian Gulf. Virus-like particle (VLP) abundance was monitored over four years at three coastal sites representing different environmental settings in Kuwait. Surface and depth samples were collected during each sampling period, along with physicochemical and nutrient data. VLP abundance fluctuated throughout the study and differed among sites and between depths. VLP counts tended to be higher at the southern site and near the surface, while the lowest values were recorded in Kuwait Bay. The three sites had distinct environmental characteristics, but relationships between VLP abundance and individual physicochemical variables varied among sites and seasons. When environmental, spatial, and temporal variables were considered together, Random Forest identified season, dissolved oxygen, and nutrients, particularly nitrate, among the important predictors of VLP abundance. Dissolved oxygen showed a nonlinear association with VLP abundance in the generalized additive model (GAM), and lower abundance at depth remained significant after accounting for the measured environmental variables, while site effects were not significant in this model. Overall, VLP abundance showed marked spatial and temporal variability across Kuwait coastal waters, with patterns associated with multiple environmental and seasonal factors. This four-year record provides a baseline for viral abundance in the northwestern Arabian Gulf and supports further investigation of the biological and environmental processes influencing viral dynamics in this highly variable coastal system.