01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-06-0270 |
| Title of Abstract | Monsoon-Driven Variability in Nutrients and Chlorophyll-a: A Time-Series Study from the Eastern Arabian Sea |
| Authors | HARSA BARDHAN DALABEHERA*, Aneesh Lotilker , S.Shivaprasad, K.N.Kumar, D.N.Rao, E.Pattabi Rama Rao, K.Santhos |
| Organisation | Indian National Centre for Ocean Information Services |
| Address | Indian National Center for Ocean Information Service Pragathi Nagar, near JNTU, Hyderabad Hyderabad, Telangana, India Pincode: 500090 E-mail: bd.harsa-p@incois.gov.in |
| Country | India |
| Presentation | Oral |
| Abstract | This study presents the outcome of the Indo-US joint program Enhancing knowledge of the Arabian sea marine environment through science and advanced training, under which a 10-days time-series observation was conducted in the Eastern Arabian Sea (EAS) from July 1 to July 10, 2024, during the monsoon period, to investigate the influence of monsoon-driven processes on water column variability and to examine the spatial variability and controlling factors of nutrient and chlorophyll biogeochemistry. During the study period in the EAS, higher salinity was consistently observed in the upper 0⿿150 m depth. The water column exhibited thermal stratification throughout the period, with temperature gradients ranging from 5 to 7°C between the upper 50⿿120 m depth. Dissolved Oxygen (DO) concentrations were significantly lower below 75 m depth across the entire study period. On the first day of the time-series study, higher surface chlorophyll-a concentrations were observed, coinciding with lower surface temperatures compared to subsequent days. Throughout most of the study period, chlorophyll-a concentrations in the upper 25 m of the water column remained low, with a prominent subsurface chlorophyll maximum (0.5⿿0.7 mg m⁻³) consistently observed between 25 and 50 m depth. This subsurface chlorophyll maximum was associated with a corresponding nitrite maximum. Elevated concentrations of nitrate, phosphate, and silicate were observed below 75 m depth. In contrast, high nitrite concentrations were detected around 50 m depth in the subsurface layer of the EAS, likely due to the advection of upwelled waters from the western parts. Nitrite concentrations showed a positive correlation with chlorophyll-a, whereas nitrate, silicate, and phosphate exhibited negative correlations. The findings of this study are highly beneficial, as they provide extensive information on temporal variability in the eastern Arabian Sea. |
| Are you part of IIOE-2 endorsed project | no |
| Keywords | Keywords: Arabian Sea; Mixing; Chlorophyll-a; Nutrient; EKAMSAT |
| For Awards | no |