Mesoscale Eddy variability and its influence on the Biological production along Western Bay of Bengal

Abstract

Bay of Bengal (BoB), the northeastern arm of the Indian Ocean is land newlinelocked on three sides and open to the Indian Ocean in the south. The newlinewestern BoB border the eastern side of Indian sub-continent. Major rivers newlineMahanadi, Godavari, Krishna and Kaveri open to the Bay on its western newlineboundary whereas the Ganges (Ganga) and the Brahmaputra open on the newlinenorthern side. The large volume of fresh water inputs from the deltaic system newlinemakes the upper layers of the Bay fresh and warm providing suitable conditions newlinefor the formation of cyclonic storms. Being a semi-enclosed basin influenced newlineby two major seasonal monsoon wind systems, the surface circulation of the newlinebasin shows distinct semiannual cycles. Under the influence of monsoons and newlineremote forcing from the Equatorial Indian Ocean, the upper layer circulation of newlinethe BoB shows basin-scale as well as mesoscale features that control the newlinebiological production and ecosystem attributes of the region. newlineThough the biological production in BoB is comparatively low due to newlinesurface stratification, the prevalence of mesoscale processes (cyclonic newlineeddies, fronts) and sporadic events (cyclones) contribute to higher newlineproduction regionally and locally. Even though the hydrography and forcing newlinemechanisms of eddies in the Bay are explained by many researchers newline(Prasannakumar et al. 2007; Nuncio, 2007; Sabu et al. 2015), the regional newlinevariability of Eddy Kinetic Energy (EKE) and its role in biological newlineproduction along the western BoB has not been attempted so far. This study newlineendeavors to bring out the eddy characteristics, its forcing mechanisms and newlinethe associated biological responses on seasonal scale covering all the newlineseasons. The study also aims to understand the interannual variability of newlinemesoscale eddies based on EKE and its influence on the chl a distribution newlineon a regional and temporal scale. newline