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Rapid Resurgence of Marine Productivity After the Cretaceous-Paleogene Mass Extinction

Science  02 Oct 2009:
Vol. 326, Issue 5949, pp. 129-132
DOI: 10.1126/science.1176233

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Algal Rebound

The extinction at the Cretaceous-Paleogene boundary 65.5 million years ago represented a sudden and dramatic disruption of global ecosystems. Sepúlveda et al. (p. 129) now show, however, that algae recovered rapidly and that photosynthesis and primary production thus also recovered. The authors tracked algal productivity in the thick boundary layer in Denmark through a series of diagnostic biomarkers and isotopes. Algal productivity dropped abruptly during the extinction event but then recovered within the boundary layer, perhaps as quickly as within 50 years of the impact.

Abstract

The course of the biotic recovery after the impact-related disruption of photosynthesis and mass extinction event at the Cretaceous-Paleogene boundary has been intensely debated. The resurgence of marine primary production in the aftermath remains poorly constrained because of the paucity of fossil records tracing primary producers that lack skeletons. Here we present a high-resolution record of geochemical variation in the remarkably thick Fiskeler (also known as the Fish Clay) boundary layer at Kulstirenden, Denmark. Converging evidence from the stable isotopes of carbon and nitrogen and abundances of algal steranes and bacterial hopanes indicates that algal primary productivity was strongly reduced for only a brief period of possibly less than a century after the impact, followed by a rapid resurgence of carbon fixation and ecological reorganization.

  • Present address: Department of Earth, Atmospheric and Planetary Sciences, MIT, 45 Carleton Street E25-623, Cambridge, MA 02139, USA.

  • Present address: Institute of Earth Sciences, Faculty of Chemistry and Earth Sciences, Friedrich-Schiller-Universität Jena, Burgweg 11, 07749 Jena, Germany.

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