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El volcado deglacial sincrónico y los cambios en la fuente de masa de agua
Natalie L Roberts1, Alexander M Piotrowski, Jerry F McManus
1Godwin Laboratory for Palaeoclimate Research, Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK. nr297@cam.ac.uk
Science (New York, N.Y.)
|January 2, 2010
Resumen
Los cambios en la circulación oceánica durante la última deglaciación fueron sincrónicos, impactando en las fuentes de aguas profundas y las tasas de vuelco. Los eventos a escala milenaria como el evento 1 de Heinrich solo afectaron el vuelco superficial, que difiere de los cambios climáticos de todo el océano.
Área de la Ciencia:
- La paleoceanografía es la paleoceanografía.
- Ciencias del clima Ciencias del clima Ciencias del clima
- La geoquímica es la geoquímica.
Sus antecedentes:
- Comprender la dinámica de la circulación oceánica es clave para descifrar los cambios climáticos pasados.
- La última deglaciación proporciona una ventana crítica a los mecanismos abruptos del cambio climático.
- La reconstrucción de los cambios en las profundidades oceánicas informa a los modelos climáticos globales.
Objetivo del estudio:
- Para reconstruir los cambios profundos en las fuentes de agua del fondo del Atlántico Norte occidental durante la última deglaciación.
- Para comparar los desplazamientos de las fuentes de masa de aguas profundas con las tasas de volcadura de los océanos.
- Para diferenciar los impactos de los eventos climáticos a escala milenaria de las transiciones deglaciales.
Principales métodos:
- Medidas de isótopos de neodimio en recubrimientos de óxido de hierro y manganeso.
- Análisis de foraminíferos planctónicos de la subida de las Bermudas.
- Comparación con los proxies existentes para la fuerza de volteo del océano.
Principales resultados:
- La fuente de masa de aguas profundas y la tasa de vuelco cambiaron rápida y sincrónicamente durante la última transición deglacial.
- Las perturbaciones de agua dulce del evento Heinrich 1 probablemente solo influyeron en el vuelco de los océanos poco profundos.
- Se observaron respuestas distintas de volcado de océanos profundos versus poco profundos a diferentes forzamientos climáticos.
Conclusiones:
- Los cambios en la circulación oceánica durante la deglaciación fueron rápidos y sincrónicos, afectando a toda la columna de agua.
- Los eventos climáticos a escala milenaria tienen un impacto más localizado en la circulación oceánica en comparación con los principales eventos de deglaciación.
- Este estudio refina nuestra comprensión del papel del océano en la regulación de las transiciones climáticas de la Tierra.
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