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GEOPHYSICAL RESEARCH LETTERS, VOL. 30, NO. 18, 1963, doi:10.1029/2003GL017928, 2003

Cambrian explosion triggered by geosphere-biosphere feedbacks

Werner von Bloh

Potsdam Institute for Climate Impact Research, Germany

Christine Bounama

Potsdam Institute for Climate Impact Research, Germany

Siegfried Franck

Potsdam Institute for Climate Impact Research, Germany

Abstract

A new hypothesis for the cause of the Cambrian explosion is presented. For that the evolution of the planet Earth is described by the co-evolution of the geosphere-biosphere system. Here we specify our previously published Earth system model for the long-term carbon cycle by introducing three different types of biosphere: procaryotes, eucaryotes, and complex multicellular life. They are characterized by different global temperature tolerance windows. The biotic enhancement of silicate weathering by complex multicellular life adds an additional feedback to the system and triggers the Cambrian explosion. The Cambrian explosion is characterized by a sudden increase of biomass and a rapid cooling, which amplified the spread of complex multicellular life. Cooling events in the Neoproterozoic, however, could force a premature appearance of complex multicellular life.

Received 10 June 2003; accepted 11 August 2003; published 27 September 2003.

Index Terms: 0330 Atmospheric Composition and Structure: Geochemical cycles; 8125 Tectonophysics: Evolution of the Earth; 9699 Information Related to Geologic Time: General or miscellaneous; 3220 Mathematical Geophysics: Nonlinear dynamics; 0315 Atmospheric Composition and Structure: Biosphere/atmosphere interactions.

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Citation: von Bloh, W., C. Bounama, and S. Franck (2003), Cambrian explosion triggered by geosphere-biosphere feedbacks, Geophys. Res. Lett., 30(18), 1963, doi:10.1029/2003GL017928.

Copyright 2003 by the American Geophysical Union.