Influence of physical processes on nutrient dynamics and phytoplankton in the coastal Bay of Bengal

Dash, M and Parida, C and Sahu, BK and Sahu, KC and Das, S (2021) Influence of physical processes on nutrient dynamics and phytoplankton in the coastal Bay of Bengal. [Book Chapter]

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Abstract

This review chapter addresses the impact of physical forcing mechanisms on spatiotemporal variation of biological productivity aided by nutrient dynamics in the nearshore waters of the Bay of Bengal (BoB) Physical forcing. The BoB has a unique physical forcing mechanism, viz., reversal pattern of monsoon wind, large freshwater influx, and remote forcing from the equator. The substantial freshwater influx into the BoB leads to strong stratification and a strong halocline below the mixed layer. Nonetheless, the strong southwest monsoon wind is inadequate to break this stratification and hence obstructs the vertical transfer of nutrients from the nutricline. This phenomenon makes the BoB oligotrophic. In contrast to this, several physical processes increase productivity by bringing nutrients from the nutricline to euphotic depths. The southwest monsoon-induced wind-driven upwelling and the ocean Ekman pumping by positive cyclonic wind stress circulation triggered by the northeast monsoon enhance the primary production in the BoB. Before the onset of the southwest monsoon, the water current along India's east coast brings more saline, cooler water to the surface by eddy-like structures, and this process causes surplus productivity in the BoB. Moreover, tropical cyclones moving over the BoB are adequate to break the stratification and thereby injecting nutrients, subject to phytoplankton blooms.

Item Type:	Book Chapter
Publication:	Estuarine Biogeochemical Dynamics of the East Coast of India
Publisher:	Springer International Publishing
Additional Information:	The copyright for this article belongs to Springer International Publishing.
Keywords:	Bay of Bengal; Chlorophyll; Nutrient dynamics; Physical forcing
Department/Centre:	Division of Mechanical Sciences > Centre for Atmospheric & Oceanic Sciences
Date Deposited:	24 Apr 2023 10:35
Last Modified:	24 Apr 2023 10:35
URI:	https://eprints.iisc.ac.in/id/eprint/81291

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