Vidya, P. J., Prasanna Kumar, S., Gauns, M., Verenkar, A., Unger, Daniela and Ramaswamy, V. (2013) Influence of physical and biological processes on the seasonal cycle of biogenic flux in the equatorial Indian Ocean. Biogeosciences Discussions, 10 (2). pp. 2889-2936. DOI https://doi.org/10.5194/bgd-10-2889-2013.

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Abstract

Seasonal cycle of biogenic fluxes obtained fromsediment trap at two locations 5◦24′N, 86◦46′E (southernBay of Bengal trap; SBBT) and 3◦34′N, 77◦46′E (equato-rial Indian Ocean trap; EIOT) within the equatorial IndianOcean (EIO) were examined to understand the factors thatcontrol them. The sediment trap data at SBBT was collectedfor ten years from November 1987 while that at EIOT wasfor a one year period from January 1996. The characteris-tic of biogenic flux at SBBT was the strong seasonality withpeak flux in August, while lack of seasonality characterisedthe flux at EIOT. The high chlorophyll biomass at the SBBTduring the summer monsoon was supported by a combina-tion of processes such as wind-mixing and advection, bothof which supplied new nitrogen to the upper ocean. In con-trast, the elevated chlorophyll at EIOT during summer mon-soon was supported only by wind mixing. High cell counts ofphytoplankton (> 5 μm) at SBBT dominated by diatoms sug-gest the operation of classical food web and high carbon ex-port. On the contrary, dominance of pico-phytoplankton andone-and-a-half time higher magnitude of micro-zooplanktonbiomass along with 2-fold lesser meso-zooplankton at EIOTindicated the importance of microbial loop. The substantialdecrease in the carbon export at EIOT indicated faster rem-ineralization of photosynthetically produced organic matter.

Document Type:	Article
Programme Area:	UNSPECIFIED
Research affiliation:	Biogeochemistry and Geology
Refereed:	Yes
Open Access Journal?:	Yes
DOI:	https://doi.org/10.5194/bgd-10-2889-2013
ISSN:	1810-6285
Date Deposited:	20 Aug 2019 13:30
Last Modified:	26 Mar 2024 13:29
URI:	http://cris.leibniz-zmt.de/id/eprint/2714

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