Role of riverine inputs, low saline plume advection and mesoscale physical processes in structuring the Chlorophyll a distribution in the western Bay of Bengal during Fall Inter Monsoon
This study delineates the role of small and medium river inputs, Low Saline Plume Advection (LSPA) and eddies in hydrography alteration and Chlorophyll a (Chl. a) in the Western Bay of Bengal. Samples were collected across five transects viz: Hooghly (HO), Mahanadi (MN), Rushikulya (RK), Visakhapatn...
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Institute of Oceanology of the Polish Academy of Sciences
2021-10-01
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| Series: | Oceanologia |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0078323421000397 |
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| author | Jagadeesan Loganathan Rao Darapu Narasimha Ignatious Joseph AswinDev Meleth Parambil Vivek Rachuri Behera Swarnaprava Balachandran Kizhakkepat Kalathil |
| author_facet | Jagadeesan Loganathan Rao Darapu Narasimha Ignatious Joseph AswinDev Meleth Parambil Vivek Rachuri Behera Swarnaprava Balachandran Kizhakkepat Kalathil |
| author_sort | Jagadeesan Loganathan |
| collection | DOAJ |
| description | This study delineates the role of small and medium river inputs, Low Saline Plume Advection (LSPA) and eddies in hydrography alteration and Chlorophyll a (Chl. a) in the Western Bay of Bengal. Samples were collected across five transects viz: Hooghly (HO), Mahanadi (MN), Rushikulya (RK), Visakhapatnam (VSKP) and Godavari (GD) during Fall Intermonsoon. Each transect consists of 7 or 8 locations from inshore to offshore. LSPA propagates southward concordance with the East India Coastal Current (EICC) and its southward flow strengthened by a cold-core eddy. LSPA results in the intermittent low salinity in the cross-shore section of HO, MN and RK. Upper layer Chl. a is 2–3 folds higher in inshore and in LSP-influenced locations than in its adjacent stations. The present study identified Double Chlorophyll a Maxima (DoCM) in LSPA-influenced slope regions of MN and RK. DoCM is less known in the BoB. DoCM has both the Surface Chl. a Maxima (SCM) and Subsurface Chl. a Maxima (SSCM). SSCM layer is relatively shallow and intense in slope and offshore regions of MN and RK due to their closeness with cold-core eddy. The present study highlights that freshwater discharge from small and medium rivers impacts hydrobiology around 10–50 km from the shore depends on the magnitude of river influx. LSPA is away from the local inputs and impacts hydrobiology (>500 km) along the path. EICC and eddies together regulated the direction of LSPA. Existing eddies nature alters vertical hydrobiology in slope and offshore regions. |
| format | Article |
| id | doaj-art-485a333f6e4f4df58731c0915fd53aee |
| institution | Kabale University |
| issn | 0078-3234 |
| language | English |
| publishDate | 2021-10-01 |
| publisher | Institute of Oceanology of the Polish Academy of Sciences |
| record_format | Article |
| series | Oceanologia |
| spelling | doaj-art-485a333f6e4f4df58731c0915fd53aee2025-08-20T03:52:04ZengInstitute of Oceanology of the Polish Academy of SciencesOceanologia0078-32342021-10-0163440341910.1016/j.oceano.2021.04.004Role of riverine inputs, low saline plume advection and mesoscale physical processes in structuring the Chlorophyll a distribution in the western Bay of Bengal during Fall Inter MonsoonJagadeesan Loganathan0Rao Darapu Narasimha1Ignatious Joseph2AswinDev Meleth Parambil3Vivek Rachuri4Behera Swarnaprava5Balachandran Kizhakkepat Kalathil6CSIR – National Institute of Oceanography, Regional Centre, Visakhapatnam, India; Corresponding author at: CSIR – National Institute of Oceanography, Regional Centre, Visakhapatnam, India.CSIR – National Institute of Oceanography, Regional Centre, Visakhapatnam, IndiaSchool of Ocean Science and Technology, Kerala University of Fisheries and Ocean Studies, Panangad, IndiaSchool of Ocean Science and Technology, Kerala University of Fisheries and Ocean Studies, Panangad, IndiaCSIR – National Institute of Oceanography, Regional Centre, Visakhapatnam, IndiaCSIR – National Institute of Oceanography, Regional Centre, Visakhapatnam, IndiaCSIR – National Institute of Oceanography, Regional Centre, Kochi, IndiaThis study delineates the role of small and medium river inputs, Low Saline Plume Advection (LSPA) and eddies in hydrography alteration and Chlorophyll a (Chl. a) in the Western Bay of Bengal. Samples were collected across five transects viz: Hooghly (HO), Mahanadi (MN), Rushikulya (RK), Visakhapatnam (VSKP) and Godavari (GD) during Fall Intermonsoon. Each transect consists of 7 or 8 locations from inshore to offshore. LSPA propagates southward concordance with the East India Coastal Current (EICC) and its southward flow strengthened by a cold-core eddy. LSPA results in the intermittent low salinity in the cross-shore section of HO, MN and RK. Upper layer Chl. a is 2–3 folds higher in inshore and in LSP-influenced locations than in its adjacent stations. The present study identified Double Chlorophyll a Maxima (DoCM) in LSPA-influenced slope regions of MN and RK. DoCM is less known in the BoB. DoCM has both the Surface Chl. a Maxima (SCM) and Subsurface Chl. a Maxima (SSCM). SSCM layer is relatively shallow and intense in slope and offshore regions of MN and RK due to their closeness with cold-core eddy. The present study highlights that freshwater discharge from small and medium rivers impacts hydrobiology around 10–50 km from the shore depends on the magnitude of river influx. LSPA is away from the local inputs and impacts hydrobiology (>500 km) along the path. EICC and eddies together regulated the direction of LSPA. Existing eddies nature alters vertical hydrobiology in slope and offshore regions.http://www.sciencedirect.com/science/article/pii/S0078323421000397River influxLow saline plume advectionMesoscale eddyChlorophyll aDouble chlorophyll maximaBay of Bengal |
| spellingShingle | Jagadeesan Loganathan Rao Darapu Narasimha Ignatious Joseph AswinDev Meleth Parambil Vivek Rachuri Behera Swarnaprava Balachandran Kizhakkepat Kalathil Role of riverine inputs, low saline plume advection and mesoscale physical processes in structuring the Chlorophyll a distribution in the western Bay of Bengal during Fall Inter Monsoon Oceanologia River influx Low saline plume advection Mesoscale eddy Chlorophyll a Double chlorophyll maxima Bay of Bengal |
| title | Role of riverine inputs, low saline plume advection and mesoscale physical processes in structuring the Chlorophyll a distribution in the western Bay of Bengal during Fall Inter Monsoon |
| title_full | Role of riverine inputs, low saline plume advection and mesoscale physical processes in structuring the Chlorophyll a distribution in the western Bay of Bengal during Fall Inter Monsoon |
| title_fullStr | Role of riverine inputs, low saline plume advection and mesoscale physical processes in structuring the Chlorophyll a distribution in the western Bay of Bengal during Fall Inter Monsoon |
| title_full_unstemmed | Role of riverine inputs, low saline plume advection and mesoscale physical processes in structuring the Chlorophyll a distribution in the western Bay of Bengal during Fall Inter Monsoon |
| title_short | Role of riverine inputs, low saline plume advection and mesoscale physical processes in structuring the Chlorophyll a distribution in the western Bay of Bengal during Fall Inter Monsoon |
| title_sort | role of riverine inputs low saline plume advection and mesoscale physical processes in structuring the chlorophyll a distribution in the western bay of bengal during fall inter monsoon |
| topic | River influx Low saline plume advection Mesoscale eddy Chlorophyll a Double chlorophyll maxima Bay of Bengal |
| url | http://www.sciencedirect.com/science/article/pii/S0078323421000397 |
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