Living planktonic foraminifera from the eastern Arabian Sea

1985 ◽  
Vol 32 (7) ◽  
pp. 789-798 ◽  
Author(s):  
Jijung Zhang
2019 ◽  
Vol 157 (3) ◽  
pp. 497-505 ◽  
Author(s):  
Ponnusamy Saravanan ◽  
Anil K. Gupta ◽  
Hongbo Zheng ◽  
Mruganka K. Panigrahi ◽  
Sameer K. Tiwari ◽  
...  

AbstractWe have analysed a 6100-year record of benthic and planktonic foraminifera from inner neritic sediments from Core SK291/GC13, off the Goa coast, eastern Arabian Sea, to understand the response of benthic foraminifera to shallow-marine processes. The benthic foraminiferal assemblage is dominated by Nonion cf. asterizans, Ammonia beccarii, A. gaimardii and Virgulinella fragilis, which have been selected on the basis of a population of 10% or more in any three samples analysed. The planktonic foraminiferal population is sporadic and rare, with Globigerinoides ruber as the predominant species showing a variable trend. The foraminiferal proxies combined with total organic carbon (wt%) and δ13C and δ18O values of Ammonia gaimardii suggest distinct variations, indicating changes in productivity and salinity in the shallow eastern Arabian Sea. The coastal waters off Goa were relatively warmer and less saline between 6100 and 4600, or perhaps to 4200, calibrated years before the present (cal yr BP), corresponding to a stronger monsoon in South and East Asia. The shallow sea was cooler from ~4200 to 2600 cal yr BP in the study area, coinciding with a lower sea surface temperature in the northeastern Arabian Sea and an arid phase in the Indian subcontinent. From 2900 to 2600 cal yr BP the study core exhibits the impacts of short-term cold events, which have earlier been observed in the northeastern Arabian Sea, off Pakistan. During the Little Ice Age, the shallow sea off Goa was less productive.


2019 ◽  
Vol 157 (6) ◽  
pp. 989-1000 ◽  
Author(s):  
Rajeev Saraswat ◽  
S. R. Kurtarkar ◽  
R. Yadav ◽  
A. Mackensen ◽  
D. P. Singh ◽  
...  

AbstractThe eastern Arabian Sea is influenced by both the advection of upwelled water from the western Arabian Sea and winter convective mixing. Therefore, sediments collected from the eastern Arabian Sea can help to understand the long-term seasonal hydrographic changes. We used the planktonic foraminifera census and stable isotopic ratio (δ18O) from sediments drilled during the International Ocean Discovery Program Expedition 355 to reconstruct surface hydrographic changes in the eastern Arabian Sea during the last 350 kyr. The increased abundance of Globigerina bulloides suggests enhanced advection of upwelled water during the latter half of MIS7 and the beginning of MIS6, as a result of a strengthened summer monsoon. A large drop in upwelling and/or advection of upwelled water from the western Arabian Sea is inferred during the subsequent interval of MIS6, based on the rare presence of G. bulloides. The comparable relative abundance of Neogloboquadrina dutertrei, G. bulloides and Globigerinoides ruber suggests that during the early part of MIS5, hydrographic conditions were similar to today. The upwelling decreased and winter convection increased with the progress of the glacial interval. A good coherence between planktonic foraminiferal assemblage-based monsoon stacks from both the eastern and western Arabian Sea suggests a coeval response of the entire northern Arabian Sea to the glacial–interglacial changes. The glacial–interglacial difference in δ18Osw-ivc was at a maximum with 4–5 psu change in salinity during Termination 2 and 3, and a minimum during Termination 4. The significantly reduced regional contribution to the glacial–interglacial change in δ18Osw-ivc during Termination 4 suggests a lesser change in the monsoon.


1999 ◽  
Vol 52 (3) ◽  
pp. 337-342 ◽  
Author(s):  
Olivia Cayre ◽  
Edouard Bard

The oxygen isotope record of planktonic foraminifera from tropical core MD77194 (Eastern Arabian Sea) exhibits a clear two-step deglaciation with a brief δ18O transient event. In the tropics, this δ18O maximum could correspond to a cooling or to a change in the δ18O content of sea water. In this study, past sea-surface temperature (SST) and primary production (PP) are reconstructed from foraminiferal transfer functions and compared to values estimated from alkenone measurements. SST and PP records from both proxies indicate a 1.5–2.5°C deglacial warming, coupled with a PP decrease, and a 0.5–1°C cooling during the Younger Dryas (YD). A detailed comparison between independent micropaleontological and geochemical proxies helps us identify potential biases and thus strengthen the paleo-reconstructions.


2017 ◽  
Vol 51 (4) ◽  
pp. 329-336
Author(s):  
Shital P. Godad ◽  
Sushant S. Naik ◽  
P. Divakar Naidu

2021 ◽  
Vol 166 ◽  
pp. 105278
Author(s):  
K.U. Abdul Jaleel ◽  
Usha V. Parameswaran ◽  
Aiswarya Gopal ◽  
Chippy Khader ◽  
V.N. Sanjeevan ◽  
...  

2017 ◽  
Vol 119 ◽  
pp. 16-23 ◽  
Author(s):  
K.V. Aneesh Kumar ◽  
V.M. Tuset ◽  
Hashim Manjebrayakath ◽  
K.S. Sumod ◽  
M. Sudhakar ◽  
...  

2016 ◽  
Vol 181 ◽  
pp. 61-69 ◽  
Author(s):  
Kunal Chakraborty ◽  
Anubhav Gupta ◽  
Aneesh A. Lotliker ◽  
Gavin Tilstone

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