- Dona Paula, Goa, India.
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| Abstract Submission No. | ABS-2022-10-0053 |
| Title of Abstract | Intrusion of Arabian Sea high salinity water and monsoon associated processes strongly modulate planktic foraminifera abundance in the southwestern Bay of Bengal |
| Authors | M. Salman*, R. Saraswat |
| Organisation | National Institute of Oceanography Goa |
| Address | salmanglb132@gmail.com Panaji, Goa, India Pincode: 403004 Mobile: 9760000287 E-mail: salmanglb132@gmail.com |
| Country | India |
| Presentation | Oral |
| Abstract | The unicellular calcareous planktic foraminifera being extremely sensitive to environmental parameters, are extensively used in paleoclimatic reconstruction. The study of surface distribution of recent planktic foraminifera and its comparison with the ambient parameters, facilitates information about the ecological preferences of the species and the factors controlling the geochemical signatures of the tests. We have used absolute and relative abundance of planktic foraminifera from 55 multicore (core-top) and 11 grab samples to understand the ecological preferences of planktic foraminifera and factors affecting its distribution in the southwestern Bay of Bengal. We found 29 species of planktic foraminifera belonging to 14 genera. The absolute abundance of planktic foraminifera was very high in the southernmost transect in front of Cauvery River where temperature and salinity both were high. Globigerinita glutinata is the highest abundant species followed by Globigerinoides ruber and Globigerina bulloides. Globigerina bulloides is abundant on the shelf, where the upwelling is more frequent. Globigerina falconensis is more abundant in the southernmost transect where upwelling is not frequent but the winter monsoon influx is more. We report that Globigerinoides ruber prefers high saline and warmer waters with the highest abundance in the southernmost transect. The southernmost transect is well within the region where high salinity Arabian Sea water intrudes during the summer monsoon season. The relative abundance of Globorotalia menardii is positively correlated with thermocline salinity and negatively correlated with thermocline temperature suggesting its preference for cold and high salinity water. Similarly, Neogloboquadrina dutertrei and Globoquadrina conglomerata are negatively correlated with mixed layer temperature and mixed layer salinity, as well as thermocline temperature and positively correlated with thermocline salinity. From the foraminiferal distribution, it is evident that the temperature and salinity of the mixed layer as well as thermocline and monsoon associated processes affect the planktic foraminifera in the southwestern Bay of Bengal. These findings will help in reconstructing paleoceanographic conditions of the Bay of Bengal. |