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Abundance and Ecology of Endemic Asterorotalia trispinosa from the Western Bay of Bengal: Implications for its Application as a Paleomonsoon Proxy
Author(s) -
SARASWAT Rajeev,
MANASA Manumalenki,
SUOKHRIE Thejasino,
SAALIM Mohammad Syed,
NIGAM Rajiv
Publication year - 2017
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/1755-6724.13463
Subject(s) - bay , relative species abundance , abundance (ecology) , euryhaline , bengal , outfall , ecology , oceanography , salinity , geography , geology , environmental science , biology , environmental engineering
A total of 97 surface sediment samples were collected from the continental shelf and slope of the western Bay of Bengal to assess the potential application of Asterorotalia trispinosa as a paleomonsoon proxy. The relative abundance of living as well as total (living and dead) A. trispinosa ranges from being absent to a maximum of ∼31%. The highest abundance of A. trispinosa is close to the outfall region of the Ganga‐Brahmaputra Rivers and decreases away from the river mouths. Contrary to that, A. trispinosa is rare in front of both the Cauvery and Pennar river outfall regions, in the central part of the western Bay of Bengal. The living A. trispinosa abundance is the lowest in between two major river systems, viz. Ganga‐Brahmaputra‐Mahanadi and Krishna‐Godavari. The relative abundance of both the total and living A. trispinosa is strongly positively correlated with ambient seawater temperature, and negatively correlated with %Corg and salinity. Based on the spatial distribution, we conclude that A. trispinosa is stenohaline in nature, rather than euryhaline, and further that the increased relative abundance of A. trispinosa indicates warmer and only marginally hyposaline environment. Even though the ecological preference of A. trispinosa suggests it as a potential paleomonsoon proxy, the restricted distribution implies limited application.