| Abstract Submission No. | ABS-1.2-0091 |
| Title of Abstract | Unravelling the Controls on Deep Chlorophyll Maxima across Southern Indian Ocean Fronts |
| Authors | Prince Prakash* |
| Organisation | National Centre for Polar and Ocean Research |
| Address | NCPOR vasco, Goa, India Pincode: 842003 E-mail: prakash@ncpor.res.in |
| Country | India |
| Presentation | Oral |
| Abstract | Southern Ocean fronts, are circumpolar transition zones between water masses. While primarily controlled by the eastward-flowing Antarctic Circumpolar Current (ACC), their paths and intensity are significantly shaped by wind and the underlying ocean floor. To investigate the pronounced physical and biogeochemical variability within the Southern Indian Ocean sector, four Bio-Argo floats were deployed across its key frontal zones during 33rd Indian Scientific Expedition to Antarctica (33-ISEA). Using high-resolution, multi-year datasets from these Bio-Argo profiling floats, this study explores the mechanisms regulating the formation and variability of Deep Chlorophyll Maxima (DCM) across the Subtropical Front (STF) and Polar Front (PF)¿key features influencing productivity and ecosystem structure in this unique region. Our results demonstrate marked contrasts between the STF and PF: the STF is characterized by warmer, saltier, and more stratified surface waters with shallower mixed layers, leading to persistent and elevated DCMs (median 1.55 mg/m³ at 42 m) throughout the year. In contrast, the PF exhibits colder, fresher waters, deeper mixed layers, and weaker stratification, resulting in deeper (median 78 m) and less intense DCMs (median 0.88 mg/m³) that display strong seasonality tied to winter mixing and reduced light penetration. Statistical analysis reveals robust correlations between DCM features, mixed layer depth, and photosynthetically active radiation (PAR), indicating that the interplay between light availability, wind-driven mixing, and water column stability governs phytoplankton biomass accumulation below the surface. This study highlight how the Southern Indian Ocean's unique oceanographic and geological settings shape its regional biogeochemistry and marine ecosystems. These findings are crucial for improving climate models, particularly for carbon sequestration, and for understanding the region's influence on global climate systems. |
| Keywords | DCM, Chlorophyll , Southern ocean |