This study presents a detailed analysis of chlorophyll- a (Chl- a ) dynamics in the Arabian Gulf over a 19-year period (2003–2021), highlighting the complex interplay between marine ecosystems and climatic influences. Using daily Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data, validated against in situ observations, we document a pronounced decline in Chl- a concentrations, with levels decreasing by approximately 16% over the study period, from elevated values in the early years to noticeably reduced concentrations in recent years. Spatial analysis revealed persistent patterns, with coastal waters exhibiting Chl- a concentrations up to threefold higher than offshore regions, influenced predominantly by riverine discharge and local anthropogenic activities. Seasonal analysis revealed peak Chl- a concentrations during winter, associated with temperatures changes and nutrient dynamics. Empirical Orthogonal Function (EOF) analysis identified three dominant modes accounting for 26% of the Chl- a variability, which are correlated with major global climate oscillations: the Indian Ocean Dipole (IOD, r = –0.78), Atlantic Multidecadal Oscillation (AMO, r = –0.74), and El Niño–Southern Oscillation (ENSO, r = –0.84). These findings highlight the Gulf’s vulnerability to environmental change, emphasizing the importance of continued monitoring and adaptive management to better understand and mitigate the impacts of climatic and anthropogenic pressures on marine ecological dynamics. • Average Chl- a concentration in the Gulf between 2003-2021 is 1.29 ±0.51 mg m −3 . • 19-year analysis reveals early high Chl- a concentrations followed by recent declines. • Contrasting Chl-a concentration trends along Eastern & Western Gulf’s coastlines. • EOF analysis identifies three dominant modes explaining 26% of Chl- a variability. • Modes of Chl- a variability correlate with global climate oscillations: ENSO, IOD, and AMO.
Senafi et al. (Sun,) studied this question.