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Secondary calcification of planktic foraminifera from the Indian sector of Southern ocean

DRS at CSIR-National Institute of Oceanography

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Title Secondary calcification of planktic foraminifera from the Indian sector of Southern ocean
 
Creator Mohan, R.
Shetye, S.
Tiwari, M.
AnilKumar, N.
 
Subject GEOLOGY AND GEOPHYSICS
 
Description This study focused on planktic foraminifera in plankton tows and surface sediments from the western Indian sector of Southern Ocean in order to evaluate the potential foraminiferal secondary calcification and/or dissolution in the sediment. It is found that the symbiotic foraminiferal species are abundant in the subtropical region, whereas non-symbiotic species dominate in the sub-Antarctic and polar frontal regions. The distribution of the symbiotic and non-symbiotic foraminiferal species is controlled by temperature, salinity, light, nutrients and phytoplankton biomass. There is also a lateral southern extent in abundance of planktic foraminifera from surface sediments to plankton tows. The shell weights of the planktic foraminifera N. pachyderma, G. bulloides and G. ruber within the surface sediments are on an average heavier by 27%, 34% and 40% respectively than shells of the same size within the plankton tows, indicative of secondary calcification. The planktic foraminiferal isotopes show the presence of heavier isotopes in the surface sediment foraminifera as compared to plankton tows, thus confirming secondary calcification. Secondary calcification in G. ruber occurs in the euphotic zone, whereas in case of N. pachyderma and G. bulloides it is at deeper depths. We also observed a decrease in the shell spines in surface sediment foraminifera as compared to plankton tows, indicative of the morphological changes that foraminifera underwent during gametogenesis.
 
Date 2015-08-21T07:30:59Z
2015-08-21T07:30:59Z
2015
 
Type Journal Article
 
Identifier Acta Geologica Sinica, vol.89(1); 2015; 27–37
http://drs.nio.org/drs/handle/2264/4748
 
Language en
 
Rights An edited version of this paper was published by John Wiley/Geological Society of China. This paper is for R & D purpose. Copyright [2015] Geological Society of China
 
Publisher Geological Society of China