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Environmental and biological controls on the diversity and ecology of Late Cretaceous through early Paleogene marine ecosystems in the U.S. Gulf Coastal Plain

Jocelyn A. Sessa, Timothy J. Bralower, Mark E. Patzkowsky, John C. Handley and Linda C. Ivany
Environmental and biological controls on the diversity and ecology of Late Cretaceous through early Paleogene marine ecosystems in the U.S. Gulf Coastal Plain
Paleobiology (March 2012) 38 (2): 218-239

Abstract

The late Mesozoic through early Cenozoic is an interval of significant biologic turnover and ecologic reorganization within marine assemblages, but the timing and causes of these changes remain poorly understood. Here, we quantify the pattern and timing of shifts in the diversity (richness and evenness) and ecology of local (i.e., sample level) mollusk-dominated assemblages during this critical interval using field-collected and published data sets from the U.S. Gulf Coastal Plain. We test whether the biologic and ecologic patterns observed primarily at the global level during this time are also expressed at the local level, and whether the end-Cretaceous (K/Pg) mass extinction and recovery moderated these trends. To explore whether environment had any effect on these patterns, we examine data from shallow subtidal and offshore settings. Assemblages from both settings recovered to pre-extinction diversity levels rapidly, in less than 7 million years. Following initial recovery, diversity remained unchanged in both settings. The trajectory of ecological restructuring was distinct for each setting in the wake of the K/Pg extinction. In offshore assemblages, the abundance and number of predatory carnivorous taxa dramatically increased, and surficial sessile suspension feeders were replaced by more active suspension feeders. In contrast, shallow subtidal assemblages did not experience ecological reorganization following the K/Pg extinction. The distinct ecological patterns displayed in each environment follow onshore-offshore patterns of innovation, whereby evolutionary novelties first appear in onshore settings relative to offshore habitats. Increased predation pressure may explain the significant ecological restructuring of offshore assemblages, whereby the explosive radiation of predators drove changes in their prey. Habitat-specific ecological restructuring, and its occurrence solely during the recovery interval, implies that disturbance and incumbency were also key in mediating these ecological changes.


ISSN: 0094-8373
EISSN: 1938-5331
Coden: PALBBM
Serial Title: Paleobiology
Serial Volume: 38
Serial Issue: 2
Title: Environmental and biological controls on the diversity and ecology of Late Cretaceous through early Paleogene marine ecosystems in the U.S. Gulf Coastal Plain
Affiliation: Pennsylvania State University, Department of Geosciences, University Park, PA, United States
Pages: 218-239
Published: 201203
Text Language: English
Publisher: Paleontological Society, Lawrence, KS, United States
References: 100
Accession Number: 2012-045526
Categories: Invertebrate paleontology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: Supplemental information/data is available in the online version of this article; NSF grants EAR-0318584, EAR-0120727, and EAR-0719645
Illustration Description: illus. incl. 5 tables
N30°00'00" - N35°00'00", W88°30'00" - W85°00'00"
N30°19'60" - N35°00'00", W85°34'60" - W80°45'00"
N30°15'00" - N35°00'00", W91°40'00" - W88°04'60"
N25°45'00" - N36°30'00", W106°30'00" - W93°30'00"
Secondary Affiliation: Xerox Corporation, USA, United StatesSyracuse University, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, Copyright, The Paleontological Society. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201224
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