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Materia orgánica joven como fuente de dióxido de carbono que emana de los ríos amazónicos
Emilio Mayorga1, Anthony K Aufdenkampe, Caroline A Masiello
1School of Oceanography, University of Washington, Seattle, Washington 98195, USA. emiliomayorga@alum.mit.edu
Nature
|July 29, 2005
Resumen
Los ríos amazónicos liberan dióxido de carbono significativo debido a la respiración de materia orgánica fresca. Una pequeña piscina de carbono de rápido ciclo impulsa estos grandes flujos desde la tierra a la atmósfera.
Área de la Ciencia:
- Ciencias ambientales Ciencias ambientales.
- Biogeoquímica La biogeoquímica es la bioquímica.
- La geoquímica de los isótopos es la geoquímica de los isótopos.
Sus antecedentes:
- Los ríos están sobresaturados de dióxido de carbono, lo que lleva a una evasión sustancial de gas.
- Los ríos amazónicos exhiben una alta emisión de dióxido de carbono, lo que afecta a los presupuestos regionales de carbono.
- Las fuentes y los tiempos de rotación del carbono respirado en los ríos siguen siendo objeto de debate.
Objetivo del estudio:
- Para investigar las fuentes y el ciclo del carbono que impulsa la sobresaturación de dióxido de carbono en los ríos amazónicos.
- Para determinar la edad y el origen de la materia orgánica respirada dentro del sistema fluvial.
- Para vincular la composición de isótopos de carbono a los flujos de evasión de dióxido de carbono.
Principales métodos:
- Estudio extensivo de la composición isotópica del carbono (13C y 14C).
- Análisis de carbono inorgánico disuelto y tres fracciones de tamaño de carbono orgánico.
- Muestreo en todo el sistema fluvial amazónico.
Principales resultados:
- La respiración de la materia orgánica contemporánea (<5 años de edad) es la fuente dominante de exceso de CO2.
- Las fracciones de carbono orgánico a granel transportadas por los ríos son significativamente más antiguas (de decenas a miles de años).
- Una pequeña piscina de carbono orgánico de rápido ciclo alimenta altos flujos de evasión.
Conclusiones:
- La materia orgánica terrestre y fluvial contemporánea alimenta la emisión de CO2 del río Amazonas.
- El ciclo rápido de una pequeña piscina de carbono orgánico es clave para comprender los grandes flujos de carbono de los ríos tropicales.
- Este hallazgo tiene implicaciones para los presupuestos regionales de carbono y los modelos climáticos.
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