Chlorophyll a distribution in the Arabian Gulf: climate, trends, and global teleconnections

The study explored the climatology, trends, and variability of Chlorophyll a concentration (hereafter ‘Chl a’) in the Arabian Gulf (hereafter ‘examined the climatology, trends, and variability of Chlorophyll a concentration (hereafter referred to as ‘Chl a’) in the Arabian Gulf (hereafter referred to as ‘Gulf’), utilizing merged satellite datasets for the period 1998–2022. Distinct spatial and temporal variabilities were identified, which are linked to climatic features, inflow from the Arabian Sea, freshwater discharge into the Gulf, and the Gulf circulation. The study identified an opposing phase in the dominance of Chl a between the southern Iranian coast and the Arabian coast. Among wind speed, sea level anomaly, and sea surface temperature (SST), multiple linear regression analysis revealed SST as the strongest predictor of phytoplankton growth. The La Niña and positive Indian Ocean dipole (IOD) phases enhanced the Chl a, while El Niño and negative IOD phases caused its decline. The Chl a increased in the northern coast and southern shelf of the Gulf, of the order concentration increasing on the northern coast and southern shelf of the Gulf, at a rate of 0.017–0.031 mg/m−3/y, while the southern Iranian coast exhibited weaker negative trends