Partial collapse of the marine carbon pump after the Cretaceous-Paleogene boundary

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doi: 10.1130/G37581.1
Author(s): Birch, Heather S.; Coxall, Helen K.; Pearson, Paul N.; Kroon, Dick; Schmidt, Daniela N.
Author Affiliation(s): Primary:
Cardiff University, School of Earth and Ocean Sciences, Cardiff, United Kingdom
Other:
Stockholm University, Sweden
University of Edinburgh, United Kingdom
University of Bristol, United Kingdom
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 44(4), p.287-290. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. GSA Data Repository item 2016088. 26 refs.; illus.
Summary: The impact of an asteroid at the end of the Cretaceous caused mass extinctions in the oceans. A rapid collapse in surface to deep-ocean carbon isotope gradients suggests that transfer of organic matter to the deep sea via the biological pump was severely perturbed. However, this view has been challenged by the survival of deep-sea benthic organisms dependent on surface-derived food and uncertainties regarding isotopic fractionation in planktic foraminifera used as tracers. Here we present new stable carbon (δ13C) and oxygen (δ18O) isotope data measured on carefully selected planktic and benthic foraminifera from an orbitally dated deep-sea sequence in the southeast Atlantic. Our approach uniquely combines δ18O evidence for habitat depth of foraminiferal tracer species with species-specific δ13C eco-adjustments, and compares isotopic patterns with corresponding benthic assemblage data. Our results show that changes in ocean circulation and foraminiferal vital effects contribute to but cannot explain all of the observed collapse in surface to deep-ocean foraminiferal δ13C gradient. We conclude that the biological pump was weakened as a consequence of marine extinctions, but less severely and for a shorter duration (maximum of 1.77 m.y.) than has previously been suggested.
Year of Publication: 2016
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; C-13/C-12; Carbon; Cenozoic; Chemostratigraphy; Cretaceous; Foraminifera; Impacts; Invertebrata; Isotope ratios; Isotopes; K-T boundary; Leg 208; Lower Paleocene; Marine sediments; Mass extinctions; Mesozoic; Microfossils; O-18/O-16; ODP Site 1262; Ocean Drilling Program; Oxygen; Paleo-oceanography; Paleocene; Paleoecology; Paleogene; Protista; Reconstruction; Sediments; South Atlantic; Stable isotopes; Stratigraphic boundary; Tertiary; Upper Cretaceous; Walvis Ridge
Coordinates: S271100 S271100 E0013500 E0013400
Record ID: 2016033026
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States, Reference includes data supplied by the Geological Society of America