Premium
On the eastward shift of winter surface chlorophyll‐a bloom peak in the B ay of B engal
Author(s) -
Martin M. V.,
Shaji C.
Publication year - 2015
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2014jc010162
Subject(s) - bay , bloom , upwelling , oceanography , bengal , phytoplankton , rossby wave , geology , ekman transport , chlorophyll a , spring bloom , algal bloom , mixed layer , advection , environmental science , nutrient , biology , ecology , botany , physics , thermodynamics
Analysis of satellite‐derived surface layer phytoplankton chlorophyll‐a concentration (Chl‐a) in the Bay of Bengal revealed an eastward shift of peak of Chl‐a bloom during northeast monsoon period (November–March) from western to the eastern Bay. The winter Chl‐a bloom in the western Bay is shorter duration (∼1–2 months) while that in the eastern Bay is longer duration (∼3–4 months). Unlike other oceans, the eastward bloom peak shift found in the Bay of Bengal is opposite to the direction of propagation of Rossby wave and seasonal mean zonal currents. During winter, sufficient light is available in the Bay of Bengal for phytoplankton growth. Herein, we studied the processes controlling the eastward winter bloom peak shift and the zonal depiction of bloom duration in the Bay of Bengal. There is no single dominant process that drives the eastward bloom peak shift everywhere in the Bay of Bengal. Rather, different physical processes operate in different regions. The physical mechanisms governing the eastward winter Chl‐a bloom peak shift reported here include open ocean Ekman pumping, coastal upwelling, upwelling driven by Rossby wave, wind‐induced vertical mixing, nutrients supply from river input, and westward advection through prevailing zonal currents.