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Impactos antropogénicos en los isótopos de nitrógeno del nitrato del núcleo de hielo
M G Hastings1, J C Jarvis, E J Steig
1Department of Geological Sciences and Environmental Change Initiative, Brown University, Providence, RI 02912, USA. meredith_hastings@brown.edu
Science (New York, N.Y.)
|June 6, 2009
Resumen
Un núcleo de hielo de Groenlandia muestra una disminución significativa en las proporciones de isótopos de nitrógeno (delta15N) de nitrato desde el período industrial. Esto indica que el aumento de las emisiones de óxido de nitrógeno (NOx) causadas por el hombre ha alterado la composición de nitratos atmosféricos.
Área de la Ciencia:
- Paleoclimatología Paleoclimatología
- Química de la atmósfera química de la atmósfera
- La geoquímica de los isótopos es la geoquímica de los isótopos.
Sus antecedentes:
- La composición isotópica del nitrato (delta15N) es sensible a las fuentes de óxido de nitrógeno (NOx).
- Los núcleos de hielo proporcionan valiosos archivos de la composición atmosférica pasada.
Objetivo del estudio:
- Para reconstruir los cambios históricos en la composición de nitrato atmosférico.
- Evaluar el impacto de las emisiones antropogénicas en los isótopos de nitrógeno.
Principales métodos:
- Análisis de un núcleo de hielo de 100 metros desde Summit, Groenlandia.
- Medición de la composición isotópica del nitrógeno (delta15N) en el nitrato.
Principales resultados:
- Se observó una fuerte y inequívoca tendencia negativa en delta15N de nitrato durante el período industrial.
- Se registró una disminución de 12 por mil en el delta15N de nitrato atmosférico desde los valores preindustriales hasta los actuales.
- El registro de nitratos del núcleo de hielo refleja con precisión los cambios en las emisiones de la fuente de óxido de nitrógeno (NOx).
Conclusiones:
- Las emisiones antropogénicas de NOx han alterado significativamente la firma isotópica del nitrato atmosférico.
- Las variaciones en la composición isotópica del nitrato pueden afectar la interpretación de otros registros ambientales.
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