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Los glaciares como fuente de materia orgánica antigua y lábil para el medio marino
Eran Hood1, Jason Fellman, Robert G M Spencer
1Environmental Science and Geography Program, University of Alaska Southeast, Juneau, Alaska 99801, USA. eran.hood@uas.alaska.edu
Nature
|December 25, 2009
Resumen
La escorrentía de los glaciares entrega materia orgánica disuelta (MDO) más antigua y más reactiva a los ecosistemas costeros. El derretimiento de los glaciares impulsado por el clima puede alterar significativamente la calidad y cantidad de esta crucial fuente de carbono marino.
Área de la Ciencia:
- Ciencias ambientales Ciencias ambientales.
- La geoquímica es la geoquímica.
- Oceanografía La oceanografía es la oceanografía.
Sus antecedentes:
- La materia orgánica fluvial es crucial para el metabolismo estuariano, soportando alrededor de una quinta parte de la misma.
- Los ecosistemas costeros son sensibles a los cambios en la cantidad y calidad de la materia orgánica disuelta (MDO) de los ríos.
- La labilidad DOM está tradicionalmente relacionada con la edad, con DOM más joven siendo más biodisponible.
Objetivo del estudio:
- Para investigar la relación entre la cobertura de los glaciares y las características de las aguas de los arroyos DOM.
- Determinar cómo los ríos alimentados por glaciares influyen en la edad y la biodisponibilidad del DOM entregado a las aguas costeras.
Principales métodos:
- Caracterización del agua de arroyo DOM de 11 cuencas hidrográficas costeras en el Golfo de Alaska con una cobertura glaciar variable (0-64%).
- Análisis de la edad (14) C y la biodisponibilidad de DOM para los microorganismos marinos.
Principales resultados:
- En contraste con los ríos no glaciares, la biodisponibilidad de DOM en los ríos glaciares se correlacionó positivamente con el aumento de la edad (14) C.
- Las cuencas hidrográficas con una alta cobertura de glaciares arrojaron el DOM más antiguo (aprox. 4 kyr) con la mayor labilidad (66% de biodisponibilidad).
- Las cuencas hidrográficas glaciares exhiben altas tasas de escurrimiento debido a la significativa pérdida de volumen de los glaciares.
Conclusiones:
- La escorrentía glacial es una fuente importante de carbono orgánico disuelto lábil para los ecosistemas marinos.
- Los cambios climáticos que afectan el volumen de los glaciares podrían alterar la edad, la cantidad y la reactividad del DOM que entra en los océanos costeros.
- Los glaciares representan una importante reserva de agua, lo que los convierte en un factor clave en la futura dinámica de carbono de los océanos costeros.
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