Biophysical coupling Chlorophyll a dynamics of the North Eastern Arabian Sea in a warming scenari

Abstract

newlineThe thesis address the role of physical drivers such as temperature, density, newlinemixing/stratification, settling velocity, and light in defining the vertical structure newlineof Chlorophyll (Chl-a) and the phytoplankton in the upper layers of the North newlineEastern Arabian Sea (NEAS). The study utilized a wide range of data from newlineBio-Argo (250 profiles from 4 floats, employing appropriate validation exercises newlineand processed/analyzed using self-developed tool Ponman), remote sensing newlinesatellites, and CTD profiles collected during the period 2003 to 2019. The newlinecrux of the study is oriented about the Gaussian characteristics of the Chl-a newlineprofile and the Stokes relation in fluid dynamics to explain Settling depth and newlinevelocity. The Principle Component Analysis (PCA) illustrates the dominant newlinerole of density( t) and its gradient over Photosynthetically Active Radiation newline(PAR). The study found significant relation of Subsurface Chlorophyll Maxima newline(SCM) with the buoyancy frequency, especially during the stratified spring newlineconditions (February-March). This change is reflected well in the settling newlinesimulations, which attempted on the ten regionally dominant species. The SCM newlineis well prominent after every bloom, and as reflected in the surface-subsurface newlineinteractions evinced in the Dynamic Time Wraps (DTW), Noctiluca scintillans newlinesubstantially contribute to the SCM. Winter-driven convective mixing and the newlinespring settling result in the ascending and descending phytoplankton in the newlinewater column. The Empirical Orthogonal Teleconnections (EOTs) show that newlinethese oscillations locally do control by the prevailing currents and mesoscale newlineprocesses like eddies. The Lotka-Volterra Model (LVM) suggests strong trophic newlinerelations between the dominant prey (diatom) and predator (Noctiluca) during newlinewinter-spring