Dos mil millones de años de oxigenación de la superficie de la Tierra
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Ver abstracta en PubMed
Resumen
Este resumen es generado por máquina.La Tierra
Área De La Ciencia
- Ciencias de la Tierra
- Biogeoquímica
- Paleoclimatología
Sus Antecedentes
- La oxigenación de la Tierra fue un proceso gradual, con detalles de la transición que permanecen poco claros.
- El aumento del oxígeno atmosférico (O2) es crucial para comprender la evolución temprana de la vida.
- Los estudios anteriores carecen de datos de alta resolución sobre el historial de oxigenación a largo plazo.
Objetivo Del Estudio
- Para reconstruir la historia de oxigenación de la Tierra usando un nuevo proxy.
- Investigar la relación entre los niveles de O2 atmosférico y la oxigenación del océano.
- Para explicar las anomalías del ciclo del carbono del Neoproterozoico y el surgimiento de la vida compleja.
Principales Métodos
- Análisis de isótopos de oxígeno independientes de la masa en el sulfato sedimentario (Δ'17Osulfato) durante 2.500 millones de años.
- Integración de los datos sedimentarios Δ33S existentes.
- Modelado biogeoquímico cuantitativo
Principales Resultados
- Una transición de 2 Gyr de la presión parcial atmosférica fluctuante de O2 (pO2) desde un estado libre de O2 a niveles modernos.
- Evidencia de pO2 elevado después de 1,0 Ga.
- Las disminuciones acopladas de Δ'17Osulfato y sulfato-δ34S durante las excursiones de isótopos de carbono del Neoproterozoico, relacionadas con el aumento de pO2.
Conclusiones
- La atmósfera y los océanos de la Tierra experimentaron una larga y dinámica historia de cooxigenación.
- La oxigenación episódica del océano fue impulsada por el aumento de la afluencia de O2 atmosférico, con mecanismos de retroalimentación negativa.
- Esta oxigenación dinámica proporciona una explicación coherente para los ciclos de carbono del Neoproterozoico y el surgimiento de la vida compleja.
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