01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-06-0293 |
| Title of Abstract | Nutrient dynamics in the Bay of Bengal during the spring 2024: Physical drivers and biological responses |
| Authors | K. Nandakumar *, K. Ashin , Aneesh A. Lotliker, Harsa Bardhan Dalabehera, Chandra Sekhar R. Naik, K. Santhosh |
| Organisation | Indian National Centre for Ocean Information Services |
| Address | ESSO-INCOIS, Pragatinagar Hyderabad, Telangana, India Pincode: 500090 E-mail: nk.kuniyil-p@incois.gov.in |
| Country | India |
| Presentation | Oral |
| Abstract | The investigation of nutrient dynamics during the oligotrophic period is crucial to understanding how productivity and ecosystem functioning are sustained under nutrient scarcity. This study examines the nutrient variability and its controlling mechanisms within the upper 200 m water column of the Bay of Bengal (BoB) (2°N to 19°N) during the spring intermonsoon (SIM) of 2024, based on in situ observation from RV Thomas G. Thompson (Cruise No. TN432). The hydrography and nutrient distributions display distinct south-north variabilities along the transect. The thermocline shift and salinity changes coincide with the subsurface variability of nitrate, phosphate and silicate. The phosphate and silicate ranged from 0.3 to 2.7μM and 0.5 to 37μM, respectively, with their variability largely regulated by physical forcing. A pronounced upshift of the nutricline between 4 °N to 8°N was linked to the westward propagating upwelling favourable Rossby wave, accompanied by a primary nitrite maximum associated with the dissolved oxygen change. High subsurface chlorophyll a (up to 1.3 μg/L) is observed in the southern stations compared to the northern stations, linked to this nutricline displacement. In the central and northern stations, mesoscale eddy-driven vertical mixing further influences nutrient variabilities and enhances nutrient supplies to the upper layers. These physically mediated processes jointly govern nutrient availability, sustain primary productivity and shape phytoplankton distribution during the oligotrophic SIM in the BoB. |
| Are you part of IIOE-2 endorsed project | no |
| Keywords | Nutrients, Bay of Bengal, Spring inter monsoon, Mesoscale eddy |
| For Awards | yes |
| Date Of Birth | 21-10-1995 |
| ECSN Registration Number | IIOE2-ECSN-0161 |