The relationship between environmental change and the extinction of the nannoplankton Discoaster in the early Pleistocene

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doi: 10.1002/2015PA002803
Author(s): Schueth, Jonathan D.; Bralower, Timothy J.
Author Affiliation(s): Primary:
Pennsylvania State University, Department of Geosciences, University Park, PA, United States
Volume Title: Paleoceanography
Source: Paleoceanography, 30(7), p.863-876. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0883-8305 CODEN: POCGEP
Note: In English. 89 refs.; illus., incl. 1 table, sketch maps
Summary: The long-ranging nannoplankton genus Discoaster went extinct in the early Pleistocene, one of the most significant events in the Cenozoic nannofossil record. The causal factors of this extinction are poorly constrained, at least partially because the ecology of Discoaster is not well understood. We investigate the relationship between the extinction and environmental changes by comparing a suite of high-resolution nannofossil assemblage data at four Ocean Drilling Program sites to published environmental proxy records. Through the use of multivariate analysis, we determine Discoaster shared environmental preferences with the extant species Florisphaera profunda which thrives in the lower photic zone near the nutricline in locations where the water column is stratified. We show that the last occurrence of Discoaster was globally diachronous, rather than synchronous as previously thought, and likely took place in the equatorial Atlantic Ocean. We propose that the demise of Discoaster was a two-stage process. A decrease in sea surface temperatures and increase in climate variability led to a global decline in Discoaster abundance. The extinction event itself correlates to shoaling of the nutricline as signified by a decrease in the carbon isotopic gradient between surface and thermocline foraminifera. We hypothesize that the combination of global cooling and a shoaling of the nutricline greatly reduced Discoaster's deepwater niche and contributed to its extinction. This may suggest that ocean stratification and the depth of the nutricline are important contributors to overall nannoplankton diversity. Abstract Copyright (2015), . American Geophysical Union. All Rights Reserved.
Year of Publication: 2015
Research Program: ODP Ocean Drilling Program
Key Words: 09 Paleontology, Paleobotany; Algae; Atlantic Ocean; Cenozoic; Climate change; Discoaster brouweri; Discoasteridae; East Pacific; Equatorial Atlantic; Equatorial Pacific; Extinction; Habitat; Leg 108; Leg 138; Leg 177; Leg 198; Lower Pleistocene; Microfossils; Mid-Atlantic Ridge; Multivariate analysis; Nannofossils; Nonmetric multidimensional scaling analysis; North Pacific; Northwest Pacific; ODP Site 1090; ODP Site 1208; ODP Site 662; ODP Site 846; Ocean Drilling Program; Pacific Ocean; Paleoclimatology; Paleoecology; Plantae; Pleistocene; Preservation; Quaternary; Shatsky Rise; South Atlantic; South Pacific; Southeast Pacific; Statistical analysis; West Pacific
Coordinates: S012325 S012324 W0114421 W0114421
S030549 S030541 W0904904 W0904906
S425449 S425449 E0085359 E0085359
N360800 N360800 E1581200 E1581200
Record ID: 2015099141
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from John Wiley & Sons, Chichester, United Kingdom