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El registro de isótopos atmosféricos de CH4 del Cuaternario Tardío sugiere que los clatratos marinos son estables
1Department of Geosciences and the Earth and Environmental Systems Institute, Pennsylvania State University, University Park, PA 16802, USA. sowers@geosc.psu.edu
Science (New York, N.Y.)
|February 14, 2006
Resumen
La desestabilización de los clatratos marinos no causó aumentos abruptos de metano atmosférico durante el último ciclo glacial. En cambio, las elevadas proporciones de metano, deuterio e isótopos de hidrógeno sugieren cambios en las emisiones de humedales y petróleo.
Área de la Ciencia:
- Paleoclimatología Paleoclimatología
- La geoquímica es la geoquímica.
- Ciencias de la atmósfera Ciencias atmosféricas.
Sus antecedentes:
- Los aumentos bruscos en el metano atmosférico (CH4) durante el último ciclo glacial se han relacionado con posibles eventos de desestabilización de clatratos.
- Los clatratos marinos poseen una relación isotópica distinta de deuterio/hidrógeno (D/H), lo que significa que su desestabilización alteraría la relación D/H del CH4 atmosférico (deltaD(CH4).
Objetivo del estudio:
- Investigar el papel de la desestabilización de clatratos marinos en los abruptos aumentos de CH4 atmosférico durante el último ciclo glacial.
- Para analizar la firma del delta D ((CH4) durante los principales eventos paleoclimáticos.
Principales métodos:
- Análisis del aire atrapado en núcleos de hielo del Segundo Proyecto de Capa de Hielo de Groenlandia.
- Medición de las proporciones de isótopos de deuterio/hidrógeno (D/H) en el metano atmosférico (deltaD(CH4)).
Principales resultados:
- Se observaron valores estables y / o decrecientes de deltaD ((CH4) durante el final del Dryas más joven, el Dryas más viejo y un período estadial.
- Estos hallazgos indican que los clatratos marinos se mantuvieron estables durante estos episodios de calentamiento abrupto.
Conclusiones:
- La desestabilización de los clatratos marinos no fue la causa de los aumentos bruscos de CH4 atmosférico observados durante los períodos glaciales estudiados.
- Es probable que los elevados valores de delta glacial D ((CH4) se atribuyan a una reducción de la relación entre las emisiones netas y brutas de CH4 de los humedales y al aumento de las emisiones basadas en el petróleo.
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