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La estratificación del océano polar en un clima frío.
Daniel M Sigman1, Samuel L Jaccard, Gerald H Haug
1Department of Geosciences, Princeton University, Princeton, New Jersey 08544, USA. sigman@princeton.edu
Nature
|March 6, 2004
Resumen
El enfriamiento global hace 2,7 millones de años aumentó la estratificación oceánica en las regiones polares. Este cambio debilitó el papel de la temperatura en la densidad de los océanos, aumentando la estratificación y amplificando potencialmente el enfriamiento global al atrapar dióxido de carbono.
Área de la Ciencia:
- Oceanografía La oceanografía es la oceanografía.
- Paleoclimatología Paleoclimatología
- Geología marina Geología marina.
Sus antecedentes:
- Los océanos de bajas latitudes están estratificados de superficie-caliente, lo que limita el intercambio atmosférico del océano profundo.
- Los océanos polares exhiben complejas estructuras de densidad influenciadas por la temperatura y la salinidad.
- La sensibilidad de la densidad del agua de mar a la temperatura disminuye cerca del punto de congelación, lo que afecta la circulación oceánica en climas fríos.
Objetivo del estudio:
- Investigar los cambios en la estratificación del océano polar durante el Plioceno tardío.
- Determinar el impacto del enfriamiento global en la estructura y la circulación de la densidad oceánica.
- Evaluar los mecanismos de retroalimentación entre la estratificación polar y el clima global.
Principales métodos:
- Análisis de núcleos de sedimentos de aguas profundas del Pacífico Norte Subártico y el Océano Austral.
- Medición de las tasas de acumulación de ópalo biogénico.
- Examen de la composición isotópica del nitrógeno sedimentario.
Principales resultados:
- Aumento de la estratificación vertical observada en ambos hemisferios a partir de hace 2,7 millones de años.
- Coincidió con la intensificación de la glaciación en el hemisferio norte y el enfriamiento global.
- El enfriamiento debilitó la temperatura de la temperatura.
Conclusiones:
- El enfriamiento del Plioceno tardío mejoró la estratificación del océano polar al reducir la temperatura.
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