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Profundización de capas mixtas durante los eventos de Heinrich: un enfoque multiplanctónico para el delta18O
Harunur Rashid1, Edward A Boyle
1College of Marine Science, University of South Florida, 140 7th Avenue South, St. Petersburg, FL 33701, USA. hrashid@marine.usf.edu
Science (New York, N.Y.)
|September 22, 2007
Resumen
Los cambios climáticos extremos durante los períodos glaciales, conocidos como eventos de Heinrich, pueden haber causado una mezcla más profunda del océano. Esto sugiere que el aumento de las tormentas intensificó la mezcla vertical de agua de deshielo en la parte superior del océano.
Área de la Ciencia:
- Paleoclimatología Paleoclimatología
- Oceanografía La oceanografía es la oceanografía.
- Ciencias del clima Ciencias del clima Ciencias del clima
Sus antecedentes:
- El último ciclo glacial presentó cambios climáticos extremos, incluidos los eventos de Heinrich caracterizados por importantes rafting sobre hielo.
- Estudios anteriores utilizaron núcleos de hielo y sedimentos marinos para documentar estas fluctuaciones climáticas.
Objetivo del estudio:
- Para investigar las condiciones de la parte superior del océano durante los eventos de Heinrich utilizando isótopos de oxígeno foraminifera planctónica.
- Para determinar si se produjeron cambios en la profundidad de la capa mixta durante estos períodos climáticos extremos.
Principales métodos:
- Análisis de las variaciones de isótopos de oxígeno en foraminíferos planctónicos de núcleos de sedimentos del Atlántico Norte.
- Comparación de los datos isotópicos de los foraminiferos que viven en capas mixtas y en la termoclina.
- Correlación de los datos foraminiferales con los proxies de núcleos de hielo y sedimentos.
Principales resultados:
- Se observaron variaciones similares de isótopos de oxígeno en tres taxones foraminiferales durante los eventos 0, 1 y 4 de Heinrich.
- Estas variaciones sugieren que la calcificación ocurrió a temperaturas similares en una columna de agua superior homogeneizada.
- La evidencia apunta a una capa de superficie mixta más profunda durante los eventos de Heinrich, particularmente en la región del cinturón de escombros arrastrados por el hielo.
Conclusiones:
- Los eventos de Heinrich se asociaron con una capa de superficie mixta más profunda en el Atlántico Norte.
- El aumento de las tormentas durante los eventos de Heinrich probablemente intensificó la mezcla vertical de los océanos.
- Esta mezcla intensificada homogeneizó la columna de agua superior, impactando los ecosistemas marinos y la dinámica climática.
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