Following the phytoplankton; tracking ocean ecosystem recovery from the K/Pg mass extinction

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Author(s): Alvarez, Sarah; Gibbs, Samantha; Bown, Paul R.; Wilson, Jamie D.; Ridgwell, Andy
Author Affiliation(s): Primary:
University of Bristol, Bristol, United Kingdom
National Oceangraphy Centre, United Kingdom
University College London, United Kingdom
Volume Title: AGU 2018 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2018; American Geophysical Union 2018 fall meeting, Washington, DC, Dec. 10-14, 2018. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: The asteroid impact at the end of the Cretaceous devastated global ocean ecosystems and caused massive disruption to marine biogeochemical cycles, with profound consequences for marine primary productivity. The magnitude of the ecosystem collapse and its path to recovery is particularly evident in the continuous and prolific fossil record of the keystone calcareous nannoplankton, which faced near-annihilation as a result of the impact. Here we present a unique, high-resolution, millennial-scale time-series dataset of nannoplankton populations at ODP Site 1209 (Pacific Ocean), and new population data from ODP Site 1262 (South Atlantic Ocean) to investigate the dynamics of the post-extinction recovery at the base of the ecosystem. We apply a suite of analytical and modelling approaches that quantify population variability, diversity and trophic status in the aftermath of the event, and use these to identify key stages of marine ecosystem and environmental recovery as they emerge. Our data reveal a post-extinction interval that is characterized by exceptional levels of evolutionary turnover, with sequential short-lived acmes of dominant new taxa, which ultimately underpin modern nannoplankton lineages. We track the succession of these dynamic pioneer populations as they give way to more stable and diverse 'background' communities. This transition includes the rapid expansion of ecologic strategies, most notably the emergence of oligotrophic-favouring assemblages, which pave the way for new, resilient populations to flourish. Our records reveal roles for species richness, morphologic disparity and ecologic innovation for re-establishing the broader marine environment and trophic system, as the biota progressively rebuilds a community that more closely resembles pre-extinction, and modern, conditions. Understanding these features and timescales of marine recovery post-K/Pg offers important insight into potential challenges facing modern ocean ecosystems against the current backdrop of rapid, ongoing environmental change.
Year of Publication: 2018
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Cenozoic; Cores; Cretaceous; Ecosystems; K-Pg boundary; Leg 198; Leg 208; Lower Paleocene; Marine sediments; Mesozoic; North Pacific; Northwest Pacific; ODP Site 1209; ODP Site 1262; Ocean Drilling Program; Pacific Ocean; Paleocene; Paleogene; Phytoplankton; Plankton; Sediments; Shatsky Rise; South Atlantic; Stratigraphic boundary; Tertiary; Upper Cretaceous; Walvis Ridge; West Pacific
Coordinates: N323900 N324000 E1583100 E1583000
S271100 S271100 E0013500 E0013400
Record ID: 2019061739
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