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Iniciación tardía de un océano superior resilientemente oxigenado
Wanyi Lu1, Andy Ridgwell2,3, Ellen Thomas4,5
1Department of Earth Sciences, Syracuse University, Syracuse, NY, USA.
Science (New York, N.Y.)
|June 2, 2018
Resumen
Los niveles de oxígeno del océano aumentaron significativamente hace unos 200 millones de años, mejorando las condiciones para la vida marina. Este estudio utilizó las relaciones yodo-calcio para rastrear estos cambios cruciales en la habitabilidad de la Tierra.
Área de la Ciencia:
- Geoquímica
- Paleoceanografía
- Ciencias del Sistema Terrestre
Sus antecedentes:
- El aumento del oxígeno oceánico y atmosférico es vital para la habitabilidad de la Tierra.
- Rastrear más allá del oxígeno disuelto cerca de los umbrales de supervivencia de los metazoos en el océano superior es un desafío.
Objetivo del estudio:
- Para reconstruir las variaciones seculares en la oxigenación del océano superior utilizando las relaciones yodo-calcio.
- Para investigar el tiempo y los conductores de los principales eventos de oxigenación del océano.
Principales métodos:
- Compilación de las proporciones extensas de yodo/calcio (I/Ca) de los carbonatos marinos.
- Análisis de registros geológicos para inferir niveles pasados de oxígeno atmosférico.
- Utilizando un modelo del sistema de la Tierra para simular cambios oceanográficos.
Principales resultados:
- Evidencia de un aumento significativo en la presión parcial de oxígeno atmosférico hace unos 400 millones de años.
- Un cambio gradual distinto en la oxigenación del océano superior a condiciones casi modernas ocurrió hace aproximadamente 200 millones de años.
- Las señales de yodo a calcio a 200 Ma están vinculadas a una remineralización más profunda de la materia orgánica.
Conclusiones:
- El estudio revela hitos clave en la historia de la oxigenación de la Tierra.
- El aumento del tamaño del plancton eucariota y la biomineralización pueden haber impulsado el evento de oxigenación oceánica de 200 Ma.
- Estos hallazgos mejoran nuestra comprensión de los factores que controlan la habitabilidad marina en escalas de tiempo geológicas.
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