Satellite and In Situ Observations of a Phytoplankton Bloom from Coastal Bay of Bengal: Role in pCO2 Modulation

• Published in: Journal of the Indian Society of Remote Sensing 2017-06, Vol.45 (3), p.513-524
• Main Authors: Roy, Rajdeep, Rao, K. H., Latha, T. Preethi, Dadhwal, Vinay Kumar, Sarma, V. V. S. S., Nagamani, P. V., Choudhury, S. B., Pondala, Seetharam
• Format: Article
• Language: English
• Subjects: Algae; Anthropogenic factors; Assimilation; Carbon dioxide; Chlorophyll; Coastal waters; Color; Cost analysis; Dynamics; Earth and Environmental Science; Earth Sciences; Human influences; In situ measurement; Microscopic analysis; Modulation; Phytoplankton; Plankton; Remote Sensing/Photogrammetry; Research Article; Satellite observation; Surface water; Water column
• ISSN: 0255-660X; 0974-3006
• DOI: 10.1007/s12524-016-0604-3

A phytoplankton bloom was monitored in coastal waters of Bay of Bengal and its influence in water column properties was investigated. Significant draw down of CO 2 was noted within the vicinity of the bloom associated with high chlorophyll biomass. Microscopic analysis revealed diatoms as the dominant population. Skeletonema costatum a diatom, reached cell density of 36,898 cells l −1 within the bloom. The lowest surface pCO 2 observed was 287 µatm at the southern end of the transect covarying with surface chlorophyll of 1.090 µg l −1 . At the northern end the surface pCO 2 went as low as 313 µatm. The pCO 2 levels below the mixed layer increased twice of that of surface value (~600 µatm). The chlorophyll values observed by Ocean Colour Monitor-2 were modestly related with the in situ measurements. The primary productivity derived from growth rate, assimilation number and maximum surface chlorophyll was 160.6 mg C m −2  day −1 leading to a modest sequestration ~of 0.08 Gg of carbon per day by the surface waters. Our observations reflects the potential role of diatom blooms on coastal carbon dynamics therefore should be carefully monitored in realm of anthropogenic changes.