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¿Acaso el enfriamiento de los océanos desencadenó la biodiversidad del Ordovícico? Pruebas de la termometría
Julie A Trotter1, Ian S Williams, Christopher R Barnes
1Research School of Earth Sciences, Australian National University, Mills Road, Canberra ACT 0200, Australia. julie.trotter@anu.edu.au
Science (New York, N.Y.)
|July 26, 2008
Resumen
El Período Ordovícico no fue un estado de invernadero, sino que se enfrió constantemente, apoyando la química moderna del océano. Este clima estable fomentó importantes radiaciones de vida y la biodiversidad aumenta durante esta era.
Área de la Ciencia:
- Paleoclimatología Paleoclimatología
- Paleontología Paleontología.
- La geoquímica es la geoquímica.
Sus antecedentes:
- El período Ordovícico es conocido por importantes radiaciones de vida, pero anteriormente se pensaba que era un estado de super invernadero.
- Las estimaciones de altas temperaturas (hasta 70°C) llevaron a especular sobre la evolución de la composición isotópica de oxígeno del agua de mar.
- Los modelos climáticos anteriores carecían de una comprensión completa de las temperaturas globales del Ordovícico y su impacto en la vida.
Objetivo del estudio:
- Para reconstruir el registro climático global del Ordovícico Temprano a los períodos Silúrico.
- Investigar el papel del clima en los aumentos de biodiversidad sin precedentes del Ordovícico.
- Para probar la hipótesis de que la composición isotópica de oxígeno del agua de mar del Ordovícico difería significativamente de los valores modernos.
Principales métodos:
- Análisis de isótopos de oxígeno de conodontes (dientes fósiles) desde el Ordovícico temprano hasta el Silúrico.
- Utilizó la tecnología de microsondas iónicas para mediciones isotópicas precisas.
- Desarrolló un nuevo registro climático global basado en estos proxies geoquímicos.
Principales resultados:
- Se identificó una tendencia de enfriamiento constante a través del Ordovícico Temprano.
- Las temperaturas ecuatoriales modernas se alcanzaron y se mantuvieron a lo largo del Ordoviciano Medio y Tardío.
- Se encontró que la composición isotópica de oxígeno del agua de mar del Ordovícico era similar a los valores modernos.
Conclusiones:
- El Período Ordovícico experimentó una tendencia de enfriamiento, no un estado de super invernadero.
- Condiciones climáticas estables y favorables, similares a las modernas, prevalecieron durante todo el Ordovícico Medio y Tardío.
- El clima jugó un papel crucial en la promoción de la notable expansión de la biodiversidad observada durante este período.
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