Is there a connection between the colors of oceanic waters near the coast and Ekman pumping? Along the coastal areas of the Bay of Bengal where I live, occasionally during the monsoon, the colors of the waters become aquamarine, only to become sky blue in color a few hours later as the sea breeze sets in. Can this be explained by coastal upwelling? If this is due to Ekman pumping where does EP take place? Over equatorial waters and is then pushed north due to a coastal current? The phenomenon has been observed during both the Indian monsoons- the south west monsoon as well as the north east monsoon i.e. that the seasonal shift in wind direction does not impact the appearance of the aquamarine color.
The width of the patch is between 200-300 meters from the coast and it is oriented parallel to the coast. Closer to the coast the color is dark greenish brown and as you go further into the open sea it is aquamarine green. There are occasional dark blue "patches"(dark blue bands) which I am presuming is phytoplankton.
Few more personal observations. It appears that the aquamarine color usually manifests itself during the mornings (when there is no breeze whatsoever). The sea presents extremely gentle waves when the aquamarine color is visible. Does that mean that the origin of the aquamarine color is "non - local" ?