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Systematic decline in benthic foraminiferal species diversity linked to productivity increases over the last 26 Ma in the Indian Ocean

Raj K. Singh and Anil K. Gupta
Systematic decline in benthic foraminiferal species diversity linked to productivity increases over the last 26 Ma in the Indian Ocean
Journal of Foraminiferal Research (July 2005) 35 (3): 219-227

Abstract

Deep-sea benthic foraminiferal species diversity from the late Oligocene-Holocene sequence of Ocean Drilling Program (ODP) Site 757, Hole B, southeastern Indian Ocean (1652 m water depth), is examined in terms of the information function (H), equitability (E), number of species (S) and Sanders" rarefied values. The values of these parameters reached their maximum about 18-15 Ma, and thereafter had a continuous stepwise decrease. Productivity increased significantly in the Indo-Pacific Ocean (the "biogenic bloom") and the oxygen minimum zone (OMZ) intensified over large parts of the Indian Ocean beginning about 15 Ma. The diversity values show more abrupt changes since 10-8 Ma, when the strength of the Indian summer monsoon substantially increased and there were significant changes in Southern Hemisphere (SH) and Northern Hemisphere (NH) ice volume. Diversity values decreased abruptly 8-6 Ma (the Chron-6 negative Carbon Shift), 3.2-2.3 Ma (major NH glaciation) and 1.6-0.9 Ma, coinciding with increased percentages of Uvigerina proboscidea, a species indicative of high surface productivity. Thus, we suggest that fluctuations in species diversity at ODP Site 757 were related to changes in productivity during the studied interval.


ISSN: 0096-1191
EISSN: 1943-264X
Coden: JFARAH
Serial Title: Journal of Foraminiferal Research
Serial Volume: 35
Serial Issue: 3
Title: Systematic decline in benthic foraminiferal species diversity linked to productivity increases over the last 26 Ma in the Indian Ocean
Affiliation: Indian Institute of Technology, Department of Geology & Geophysics, Kharagpur, India
Pages: 219-227
Published: 20050701
Text Language: English
Publisher: Cushman Foundation for Foraminiferal Research, Ithaca, NY, United States
References: 62
Accession Number: 2005-062478
Categories: StratigraphyIsotope geochemistry
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table, sketch map
S17°01'28" - S17°01'23", E88°10'48" - E88°10'54"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Abstract, Copyright, Cushman Foundation for Foraminiferal Research. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 200521
Program Name: ODPOcean Drilling Program
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