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Ciclo del nitrógeno. Ciclo rápido de óxido nitroso en el océano suboxico
Andrew R Babbin1, Daniele Bianchi2, Amal Jayakumar3
1Department of Geosciences, Princeton University, Princeton, NJ 08544, USA. Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. babbin@mit.edu.
Science (New York, N.Y.)
|June 6, 2015
Resumen
El ciclo del óxido nitroso (N2O) oceánico es más rápido de lo que se pensaba, especialmente en las zonas suboxicas. Este rápido ciclo, impulsado por los niveles de carbono y oxígeno orgánicos, sugiere el aumento de las emisiones de gases de efecto invernadero del océano.
Área de la Ciencia:
- Oceanografía La oceanografía es la oceanografía.
- Química de la atmósfera química de la atmósfera
- Biogeoquímica La biogeoquímica es la bioquímica.
Sus antecedentes:
- El óxido nitroso (N2O) es un potente gas de efecto invernadero y una sustancia que agota el ozono estratosférico.
- Las fuentes oceánicas y los sumideros de N2O no se comprenden bien, lo que dificulta el modelado climático preciso.
- Las regiones suboxicas en el océano son áreas críticas pero mal cuantificadas para el ciclo del N2O.
Objetivo del estudio:
- Para medir directamente las tasas de reducción de N2O en el Pacífico Norte tropical oriental.
- Para cuantificar las tasas de ciclo de N2O en las zonas suboxicas oceánicas.
- Comprender los factores que controlan el ciclo del N2O y sus implicaciones para las emisiones atmosféricas.
Principales métodos:
- Se utilizaron marcadores de isótopos estables para medir directamente las tasas de reducción de N2O.
- Mediciones realizadas en el Pacífico Norte tropical oriental.
- Analizó la distribución espacial del ciclo de N2O en relación con los factores ambientales.
Principales resultados:
- Se encontró que las tasas de ciclos de N2O en regiones suboxicas eran un orden de magnitud mayor que las predicciones actuales del modelo debido a la desnitrificación incompleta.
- Las tasas de ciclo de N2O mostraron una fuerte dependencia del carbono orgánico y las concentraciones de oxígeno disuelto.
- La rotación de N2O fue 20 veces mayor que el flujo atmosférico neto, lo que indica un importante procesamiento oceánico.
Conclusiones:
- El ciclo oceánico de N2O está significativamente subestimado en los modelos actuales, particularmente en entornos suboxicos.
- El rápido ciclo y la dependencia de los factores ambientales sugieren que la expansión de las zonas suboxicas aumentará las emisiones de N2O.
- La cuantificación precisa de los flujos oceánicos de N2O es crucial para predecir el cambio climático futuro y el agotamiento de la capa de ozono.
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