Faunal evidence for reduced productivity and uncoordinated recovery in Southern Hemisphere Cretaceous-Paleogene boundary sections
Martin Aberhan1, , Sven Weidemeyer1, Wolfgang Kiessling1, Roberto A. Scasso2, Francisco A. Medina2
1. Museum für Naturkunde, Humboldt-Universität Berlin, Invalidenstrasse 43, D-10115 Berlin, Germany, 2. Departamento de Ciencias Geológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, 1428 Buenos Aires, Argentina
The mass extinction at the Cretaceous-Paleogene boundary is generally explained by a severe crisis in primary productivity, following a catastrophic bolide impact. Consistent with this scenario, Danian mollusk-dominated benthic shelf ecosystems of southern middle paleolatitudes (Neuquén Basin, Argentina) are characterized by (1) a stratigraphically limited low in macrofossil abundances; (2) an increase in starvation-resistant, nonplanktotrophic deposit feeders and chemosymbionts; (3) a reduction in the average body size of individuals; and (4) individuals with inactive lifestyles being more common than in the late Maastrichtian. Return to pre-extinction conditions of the various synecological attributes occurred over unequal time spans, indicating that recovery was uncoordinated with respect to ecological traits. Global comparison of ecological patterns suggests that reduced food supply (1) was a controlling factor in both hemispheres; (2) affected macrobenthic marine faunas at various distances from the Chicxulub impact site; and (3) was more effective in siliciclastic environments as compared to oligotrophic carbonate settings.
Keywords: mass extinction, Cretaceous-Paleogene boundary, ecology, productivity, Southern Hemisphere
Received: 14 July 2006; Revised: 10 October 2006; Accepted: 12 October 2006
Interesting! If anybody wants it I can get the PDF the next time I am in the office. Martin Aberhan is a cautious man, but the way I read the abstract it means that there really was a massive (I should rather say MASSIVE) disturbance of the food chain right at the K/T boundary. Mark another one for the impact theory!
Martin Aberhan1, , Sven Weidemeyer1, Wolfgang Kiessling1, Roberto A. Scasso2, Francisco A. Medina2
1. Museum für Naturkunde, Humboldt-Universität Berlin, Invalidenstrasse 43, D-10115 Berlin, Germany, 2. Departamento de Ciencias Geológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, 1428 Buenos Aires, Argentina
The mass extinction at the Cretaceous-Paleogene boundary is generally explained by a severe crisis in primary productivity, following a catastrophic bolide impact. Consistent with this scenario, Danian mollusk-dominated benthic shelf ecosystems of southern middle paleolatitudes (Neuquén Basin, Argentina) are characterized by (1) a stratigraphically limited low in macrofossil abundances; (2) an increase in starvation-resistant, nonplanktotrophic deposit feeders and chemosymbionts; (3) a reduction in the average body size of individuals; and (4) individuals with inactive lifestyles being more common than in the late Maastrichtian. Return to pre-extinction conditions of the various synecological attributes occurred over unequal time spans, indicating that recovery was uncoordinated with respect to ecological traits. Global comparison of ecological patterns suggests that reduced food supply (1) was a controlling factor in both hemispheres; (2) affected macrobenthic marine faunas at various distances from the Chicxulub impact site; and (3) was more effective in siliciclastic environments as compared to oligotrophic carbonate settings.
Keywords: mass extinction, Cretaceous-Paleogene boundary, ecology, productivity, Southern Hemisphere
Received: 14 July 2006; Revised: 10 October 2006; Accepted: 12 October 2006
Interesting! If anybody wants it I can get the PDF the next time I am in the office. Martin Aberhan is a cautious man, but the way I read the abstract it means that there really was a massive (I should rather say MASSIVE) disturbance of the food chain right at the K/T boundary. Mark another one for the impact theory!
