01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-04-0263 |
| Title of Abstract | IMPACT OF CLIMATE VARIABILITY ON PHYTOPLANKTON DYNAMICS IN THE INDIAN OCEAN |
| Authors | Haritha M*, Abhinav Gummalla, Dr. PV Nagamani, Anju Kumari |
| Organisation | National Remote Sensing Centre- Hyderabad, CUSAT |
| Address | Manazhithodi (House), Kunnakkavu post, Malappuram, 679340 Perinthalmanna, Kerala, India Pincode: 679340 E-mail: haridasharitha1996@gmail.com |
| Country | India |
| Presentation | Oral |
| Abstract | The Indian Ocean basin, particularly its western sector, is among the most biologically productive tropical ocean regions, driven by strong monsoon dynamics and basin-scale mesoscale processes. However, this productivity is increasingly threatened by rapid surface warming, which has reduced phytoplankton abundance by up to 20% in recent decades. To better understand the climate controls on biological variability, we analyzed two decades (2000⿿2024) of satellite-derived chlorophyll a (Chl-a), sea surface temperature (SST), and sea level anomaly (SLA) data, focusing on the influence of the Indian Ocean Dipole (IOD) and El Niño⿿Southern Oscillation (ENSO). Time series and Hovmöller analyses highlight substantial seasonal and interannual Chl-a variability, particularly in the western Indian Ocean during the summer monsoon. Cross-correlation and variance decomposition reveal that, over the long term, both ENSO and IOD significantly modulate productivity, but their relative roles have shifted. ENSO emerged as the dominant driver across most basins, explaining up to 75⿿80% of Chl-a variance in 2023 (e.g., Somali and Mascarene basins). In contrast, the IOD⿿s contribution weakened markedly (from 33.4% to 6.6% in the Central Indian Ocean), though it remained influential in the Bay of Bengal. A high positive ENSO⿿IOD correlation in 2023 (r = 0.94) amplified shared climatic forcing, altered lead⿿lag relationships, and intensified chlorophyll variability beyond the effect of either mode alone. Our findings underscore that analyzing long-term Chl-a variability while characterizing ENSO⿿IOD interactions at basin and regional scales strengthens understanding of how climate-driven physical processes regulate phytoplankton dynamics. This integrative perspective is critical for forecasting ecosystem responses and guiding sustainable marine resource management under accelerating climate variability and change. |
| Are you part of IIOE-2 endorsed project | no |
| Keywords | Ocean productivity, Climate change, IOD, ENSO, Ocean Physical processes, SLA, SST |
| For Awards | yes |
| Date Of Birth | 18-11-1996 |
| ECSN Registration Number | IIOE2-ECSN-0252 |