The Bay of Bengal (BoB) has emerged as one of the world's most climate-sensitive marine regions, where intensifying extreme events are increasingly transforming upper-ocean dynamics and marine productivity, supporting nearly 8 % of global fishery production, making it vital for regional food security. Satellite and observational analyses reveal a significant basin-wide warming trend of approximately +0.019 °C yr⁻¹, accompanied by strengthening stratification that alters nutrient supply, with coastal regions exhibiting chlorophyll-a increases exceeding 1 µg m⁻³ yr⁻¹, while offshore oligotrophic waters decline due to diminished vertical mixing. Marine heatwaves are increasing at ~1.11 events per decade, further intensifying stratification and ecosystem stress. High-resolution datasets demonstrate pronounced seasonal mixed layer variability — deepening to ~24 m in monsoon and shoaling to ~12 m in spring, contributing to persistently low offshore chlorophyll-a of ~0.27 ± 0.15 mg m⁻³. This seasonally fluctuating stratification also underpins broader circulation responses to climate variability, as positive Indian Ocean Dipole and El Niño events generate Rossby and Kelvin waves that foster cyclonic eddies with 15–20 % higher kinetic energy in the western Bay. Extreme climate events amplify these dynamics. Tropical Cyclone Heat Potential exceeding ~160 kJ cm⁻² fueled the rapid intensification of Super Cyclone Amphan, and storm-driven mixing temporarily reduced dissolved oxygen to ~196 mmol m⁻³, within a basin already hosting a persistent ~60,000 km² oxygen minimum zone. Concurrent biogeochemical stressors include accelerated ocean acidification, with surface pH declining at 0.004–0.006 yr⁻¹, relative sea level rise of 0.32–0.84 m by 2100 and salinity intrusion advancing ~20 km inland. These pressures are driving cascading ecological impacts, including coastal erosion, declines in artisanal fisheries, and coral diversity loss. In response, quantitative ecosystem-based management, leveraging Multi-Criteria Evaluation models that integrate satellite and ocean model data, is essential to map climate extreme and productivity hotspots. Translating these insights into effective scientific management requires prioritizing ecosystem-based approaches and anticipatory monitoring to safeguard marine productivity and ecosystem resilience in the BoB.
 

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