01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-03-0294 |
| Title of Abstract | Coastal upwelling and river influx shape mesozooplankton communities along the central west coast of India (off Goa) during the southwest monsoon |
| Authors | Sambathkumar Ravi*, Karnan chinnadurai |
| Organisation | CSIR-National institute of oceanography |
| Address | CSIR -NIO HQ , DONA PAULA PANJIM, Goa, India Pincode: 403004 E-mail: sambathkumar26401@gmail.com |
| Country | India |
| Presentation | Oral |
| Abstract | Zooplankton, being highly responsive to environmental variability, serve as vital indicators of ecological conditions in marine ecosystems. This study examines the impact of hydrographical changes on the mesozooplankton (0.2 - 2 mm) community in the coastal waters of Goa (central west coast of India) during the southwest monsoon (SWM). Mesozooplankton samples were collected during two contrasting seasons, SWM (Sep. 2022; n=4) and northeast monsoon (NEM; Dec. 2022; n=4). Abundance and biovolume were quantified using a FlowCAM imaging system, while temperature and salinity profiles were measured with a portable CTD sensor. The water column during the SWM was characterized by a thick, low-salinity (avg. 26.2 ± 1.3 PSU) nearshore layer and high-salinity offshore waters (avg. 33.3 ± 0.9 PSU). In contrast, during the NEM, salinity remained uniformly high across all sites (avg.34.2 ± 0.37 PSU). Mean abundance was higher during the SWM (avg. 1485 ± 1007 ind./m³) than the NEM (avg. 961 ± 455 ind./m³), but the greater variability during the SWM suggested a less stable population. During the SWM, abundance was higher in the low-salinity location (1727 ind./m³), lowest at the frontal zone (283 ind./m³), and gradually increased offshore (up to 2399 ind./m³). Whereas during the NEM, abundance remained relatively stable up to the third location (avg. 732 ± 136 ind./m³) before declining at the offshore station (111 ind./m³). Low-salinity waters were dominated by calanoid copepods, particularly Acartia sp., and cladocera (Penilia sp.), whereas Corycaeus sp., siphonophora, and Evadne sp dominated in high-salinity offshore waters. In contrast, the NEM showed relatively uniform salinity and a more consistent zooplankton community. The peculiar coastal-to-offshore distribution observed during the SWM can be attributed to the co-occurrence of coastal upwelling and river influx. These processes enhanced nutrient availability and created strong density gradients, driving greater variability in zooplankton distribution across nearshore waters. |
| Are you part of IIOE-2 endorsed project | no |
| Keywords | zooplankton; river influx; upwelling; stratification; southwest monsoon; central eastern Arabian Sea |
| For Awards | yes |
| Date Of Birth | 26-04-2001 |
| ECSN Registration Number | IIOE2-ECSN-0166 |