Benthic foraminiferal response to the middle Eocene Climatic Optimum (MECO) in the south-eastern Atlantic (ODP Site 1263)

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doi: 10.1016/j.palaeo.2014.10.004
Author(s): Boscolo Galazzo, Flavia; Thomas, Ellen; Giusberti, Luca
Author Affiliation(s): Primary:
University of Padova, Department of Geosciences, Padua, Italy
Other:
Yale University, Department of Geology and Geophysics, United States
Wesleyan University, Department of Earth and Environmental Sciences, United States
Volume Title: Palaeogeography, Palaeoclimatology, Palaeoecology
Source: Palaeogeography, Palaeoclimatology, Palaeoecology, Vol.417, p.432-444. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0031-0182 CODEN: PPPYAB
Note: In English. 127 refs.; illus., incl. 2 plates, sketch map
Summary: The response of marine biota to the middle Eocene Climatic Optimum (MECO) is still poorly constrained. Specifically, changes in deep-sea benthic foraminiferal faunas have been documented at few locations only. We carried out a quantitative study of benthic foraminiferal assemblages at lower-bathyal ODP Site 1263 (Walvis Ridge, SE Atlantic), providing documentation of the response of benthic foraminiferal assemblage to the MECO in an open ocean setting. There was no major temporary or persistent assemblage turnover in benthic foraminiferal faunas in the SE Atlantic Ocean. The benthic foraminiferal accumulation rates (BFAR) and assemblage composition indicate that the delivery of food to the seafloor increased during the early stages of surface and deep-sea warming. During this period, the absolute and relative abundance of phytodetritus exploiters increased pronouncedly, indicating that the increase in the flux of organic matter to the sea floor was largely seasonal or otherwise pulsed. During later stages and peak warming of MECO, in contrast, the flux of organic matter to the seafloor declined markedly, as shown by a decrease in both infaunal and epifaunal benthic foraminiferal accumulation rates. The low flux of organic matter during the more extreme parts of the MECO thus did not favor one of these broad groups, but affected all common taxa. Paleoceanographic reconstructions combined with data on benthic foraminifera suggest that the MECO warming was the main cause of the reduction in the flux of organic matter to the sea floor, by increasing the metabolic rates of pelagic consumers, which thus used more food, preventing it from reaching the sea floor, as well as increasing remineralization of organic matter in the water column. Abstract Copyright (2015) Elsevier, B.V.
Year of Publication: 2015
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Benthic taxa; Cenozoic; Detritus; Eocene; Foraminifera; Global change; Global warming; Invertebrata; Leg 208; Microfossils; Middle Eocene; Middle Eocene Climatic Optimum; ODP Site 1263; Ocean Drilling Program; Paleo-oceanography; Paleobathymetry; Paleogene; Protista; Reconstruction; South Atlantic; Southeast Atlantic; Tertiary; Walvis Ridge
Coordinates: S283200 S283200 E0024700 E0024700
Record ID: 2015026417
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands