The Xiamen Symposium on Marine Environmental Sciences

2027 Xiamen Symposium on Marine Environmental Sciences

January 12-15, 2027

Shifts in Ocean Dynamics and Marine Productivity in the Bay of Bengal under Extreme Climate Events
ID:679 Oral Presentation

2027-01-14 15:35 (China Standard Time)

Session:Session 42 - Indian Ocean Under Stress: Dynamics, Biogeochemistry, and Productivity Shifts During Extreme Events

Abstract
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.
 
Speaker
K M Azam Chowdhury University of Dhaka

Author
K M Azam Chowdhury University of Dhaka

    Important Dates

    • Jan 30

      2026

      Session / Event proposals open

    • Mar 31

      2026

      Session / Event proposals close
      (Extended to April 7)

    • Apr 30

      2026

      Session acceptance notifications

    • Apr 30

      2026

      Abstract submissions & registration open

    • Jun 30

      2026

      Abstract submissions close
      (Extended to July 21)

    • Aug 31

      2026

      Abstract acceptance notifications

    • Sep 15

      2026

      Scientific program released

    • Oct 15

      2026

      Early bird registration closes

    • Jan 12–15

      2027

      XMAS 2027