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Limitación del fósforo de la fijación de nitrógeno por Trichodesmium en el Océano Atlántico central
S A Sañudo-Wilhelmy1, A B Kustka, C J Gobler
1Marine Sciences Research Center, State University of New York, Stony Brook, New York 11794-5000, USA. ssanudo@notes.cc.sunysb.edu
Nature
|May 3, 2001
Resumen
La fijación de nitrógeno marino, crucial para la productividad del océano, no está limitada únicamente por el hierro. Este estudio revela que el contenido de fósforo y los niveles de luz son factores clave que influyen en la fijación de nitrógeno por Trichodesmium cyanobacteria.
Área de la Ciencia:
- Ecología microbiana marina ecología microbiana marina.
- Los ciclos biogeoquímicos son ciclos biogeoquímicos.
- Oceanografía La oceanografía es la oceanografía.
Sus antecedentes:
- La fijación de nitrógeno marino suministra nutrientes esenciales al fitoplancton, lo que tiene un impacto en el ciclo global del carbono.
- El cianobacterium Trichodesmium es el principal motor de la fijación de nitrógeno en aguas tropicales.
- Las suposiciones anteriores sugerían que la disponibilidad de hierro limita la fijación de nitrógeno marino.
Objetivo del estudio:
- Investigar los factores que controlan las tasas de fijación de nitrógeno marino.
- Reevaluar el papel del hierro frente a otros nutrientes en la regulación de la fijación de nitrógeno por Trichodesmium.
Principales métodos:
- Observaciones de campo en el Atlántico central.
- Medidas de las tasas de fijación de nitrógeno, hierro disuelto, contenido de Trichodesmium en hierro y contenido de fósforo.
- Análisis de la irradiación y su correlación con la fijación de nitrógeno.
Principales resultados:
- Las tasas de fijación de nitrógeno fueron independientes del contenido de hierro disuelto y Trichodesmium de hierro.
- La fijación de nitrógeno está fuertemente correlacionada con el contenido de Trichodesmium phosphorus.
- Una mayor irradiación aumentó las tasas de fijación de nitrógeno.
- Los requisitos calculados de hierro estructural para fijadores de nitrógeno son más bajos de lo estimado previamente.
Conclusiones:
- La fijación de nitrógeno marino no está regulada únicamente por el suministro de hierro.
- La disponibilidad de fósforo y la luz son factores críticos que controlan la fijación del nitrógeno.
- Si bien el hierro puede limitar el crecimiento en regiones específicas, no es el factor limitante universal.
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