This study investigates the spatial and seasonal variability of hydrographic parameters and nutrients in Doha’s coastal waters to assess links to wastewater discharges and local hydrodynamics. In situ data were collected from 11 coastal stations and 3 wastewater outfalls across two seasons. Key findings reveal a system governed by seasonal patterns, anthropogenic inputs, and distinct nearshore-offshore gradients in physical processes. The observed seasonal differences in sea surface temperature and salinity are 7.3 °C and 3.3, respectively. Dissolved oxygen peaked in winter (March: up to 7.28 mg/L) and declined in summer (June: down to 5.93 mg/L). Spatially, nutrient dynamics were strongly influenced by proximity to anthropogenic sources. Summer outfall discharges led to localized exceedances of Qatar's seawater quality standards for nitrate and silicate. Nutrient stoichiometry indicated phosphorus limitation within the nutrient-enriched bay but nitrogen limitation in well-flushed offshore waters. Statistical correlations underscored these dynamics, with temperature positively correlated and salinity negatively correlated with key nutrients and pH, reflecting the summer discharge signal. Crucially, the study documents a significant improvement in water quality during winter, following the managed reduction of outfall discharges. This demonstrates that active control of wastewater inputs can rapidly mitigate nutrient pollution in this restricted coastal embayment.
Hasna et al. (Wed,) studied this question.