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GEOSPHERE-BIOSPHERE FEEDBACKS AS A TRIGGER FOR THE CAMBRIAN EXPLOSION. Werner von Bloh, Christine Bounama, Siegfried Franck Potsdam Institute for Climate Impact Research P.O. Box 601203, 14412 Potsdam, Germany. CAMBRIAN EXPLOSION. Biological Big Bang 540 million years ago
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GEOSPHERE-BIOSPHERE FEEDBACKS AS A TRIGGER FOR THE CAMBRIAN EXPLOSION Werner von Bloh, Christine Bounama, Siegfried Franck Potsdam Institute for Climate Impact Research P.O. Box 601203, 14412 Potsdam, Germany
CAMBRIAN EXPLOSION • Biological Big Bang 540 million years ago • Most modern animal groups appear Why did it happened, when it happened?
Model description Franck et al. Tellus 54B, 325, 2002
Geosphere-biosphere feedbacks Biological productivity:
Geosphere-biosphere feedbacks Biological enhancement of weathering: (Lenton and von Bloh, GRL 28 (9),1715, 2001)
Model results Evolution of global surface temperature. Evolution of the cumulative biosphere pools for procaryotes, eucaryotes, and complex multicellular life.
Conclusions • The Cambrian explosion could have been triggered by nonlinear geosphere-biosphere interactions (von Bloh et al., GRL 30 (18), 1963, 2003). • External perturbations (e.g. „snowball Earth“ events, continental breakup) have the potential to initiate an earlier appearance of complexmulticellular life. • The model exhibits bistability for a certain range of the biotic enhancement factor.