T163 Surf to Sea, Small to Large, Bottom to Top: Ecosystem Perspectives on the Marine Fossil Record II

Wednesday, 28 October 2020
5:30 PM - 8:00 PM
Meeting Rooms

THE ROLE OF THE MARINE BIOLOGICAL PUMP IN DRIVING ECOSYSTEM RECOVERY FOLLOWING THE CRETACEOUS-PALEOGENE (K-PG) MASS EXTINCTION EVENT

Paper number: T163-3
Program: Technical Sessions
Time: 5:50 PM – 6:00 PM

Authors

Abstract

The Cretaceous-Paleogene (K-Pg) mass extinction event (~66 Ma) led to the eradication of >75% of marine species on Earth. One of the biggest consequences of the mass extinction was the apparent weakening of the biological pump: the mechanism whereby organic matter is exported from the surface to deep ocean and is eventually sequestered in deep-sea sediments. Although there was only a transient reduction in the strength of the biological pump immediately after the K-Pg extinction, several records have shown that the efficiency of the biological pump took >2 million years to recover. In addition, its complete restoration was temporally heterogeneous, perhaps due to paleoceanographic differences between ocean basins and marine environments.

Previous research indicates that planktic foraminiferal feeding strategies and adaptations changed in tandem with stages in the recovery of the biological pump, with symbiont-bearing forms only becoming dominant once pump efficiency was high and nutrient availability in shallow waters was low. Less work has been conducted to determine whether similar evolutionary patterns can be recognized in the phytoplankton, which are a keystone at the base of the marine food web. Here, we use the extensive and globally distributed record of calcareous nannoplankton (unicellular, golden-brown algae) at two geographically-disparate K-Pg sites (El Kef; Tunisia and the Chicxulub impact crater; Gulf of Mexico), to show that switchovers in low diversity, high abundance paleo-blooms (“boom-bust successions”) were also a direct response to the restoration of biological pump efficiency. Possible boom-bust successions are also recognized in other taxonomic groups such as the planktic foraminifera, benthic foraminifera, bivalves, and gastropods during the early Danian, suggesting that the biological pump was key in driving the restoration of the entire marine ecosystem following the mass extinction event. As the recovery of multiple taxonomic groups appear to be intrinsically linked, future work should focus on combining these disparate paleoecological datasets to gain a more holistic understanding of how entire marine ecosystems recover following extreme environmental perturbation.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-358244

© Copyright 2020 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.