Nitrogen uptake in the northeastern Arabian Sea during winter cooling

Content Provider	CSIR - National Institute of Oceanography (NIO)
Author	Kumar, S. Ramesh, R. Dwivedi, R. M. Raman, M. Sheshshayee, M. S. Desouza, W.
Abstract	The uptake of dissolved inorganic nitrogen by phytoplankton is an important aspect of the nitrogen cycle of oceans. Nitrate (NO sub(3) sup(-) and ammonium (NH sub(4) sup(+) uptake rates in the northeastern Arabian Sea using sup(15) N tracer technique are presented. In this relatively underexplored region, productivity is high during winter due to supply of nutrients by convective mixing caused by the cooling of the surface by the northeast monsoon winds. Studies done during different months (January and late February-early March) of the northeast monsoon 2003 revealed a fivefold increase in the average euphotic zone integrated NO sub (3) sup(-) uptake from January (2.3 mmolN m sup(-2) d sup(-1)) to late February-early March (12.7 mmolN m sup(-2) d sup(-1)). The f-ratio during January appeared to be affected by the winter cooling effect and increased by more than 50% from the southernmost station to the northern open ocean stations, indicating hydrographic and meteorological control. Estimates of NO sub(3) sup(-) residence time suggested that NO sub(3) sup(-) entrained in the water column during January contributed to the development of blooms during late February-early March.
Starting Page	11
File Format	PDF
ISSN	16879406 16879414
Journal	International Journal of Oceanography
DOI	10.1155/2010/819029
Language	English
Publisher	Hindawi Publishing Corporation
Access Restriction	Authorized
Subject Keyword	Nitrogen uptake Nitrogen cycle Phytoplankton Primary production
Content Type	Text
Resource Type	Article