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Los nadadores que migran verticalmente generan remolinos a escala de agregación en una columna estratificada
Isabel A Houghton1, Jeffrey R Koseff1, Stephen G Monismith1
1Bob and Norma Street Environmental Fluid Mechanics Laboratory, Civil and Environmental Engineering, Stanford University, Stanford, CA, USA.
Nature
|April 20, 2018
Resumen
El zooplancton marino, como el camarón de salmuera, crea grandes remolinos durante la migración vertical, mejorando significativamente la mezcla oceánica. Su movimiento colectivo conduce a la turbulencia, impactando la física del océano y el transporte de nutrientes.
Área de la Ciencia:
- La oceanografía
- Oceanografía biológica
- Dinámica de fluidos
Sus antecedentes:
- La turbulencia generada biológicamente es crucial para la mezcla oceánica y el transporte de nutrientes.
- Estudios anteriores sugirieron que la turbulencia generada por los animales es demasiado pequeña para afectar a la mezcla de los océanos.
- Las agregaciones de zooplancton durante la migración introducen nuevas escalas de longitud relevantes para la mezcla oceánica.
Objetivo del estudio:
- Para investigar si el comportamiento colectivo del zooplancton puede generar turbulencias a gran escala.
- Para cuantificar la eficiencia de mezcla de la turbulencia inducida por el zooplancton.
- Evaluar el impacto del zooplancton en la estratificación y mezcla de los océanos.
Principales métodos:
- Simulación experimental de la migración del zooplancton (Artemia salina) a escala de centímetros.
- Medición de la generación de remolinos y mezcla en un fluido estratificado.
- Analizando la escala de la turbulencia en relación con la estratificación de la densidad.
Principales resultados:
- La migración colectiva de los camarones de salmuera genera remolinos a escala de agregación.
- Estos remolinos mezclan efectivamente la estratificación de densidad estable.
- Se observó que la difusividad turbulenta era hasta tres órdenes de magnitud mayor que la difusividad molecular.
Conclusiones:
- Las agregaciones de zooplancton marino pueden alterar significativamente la física de la columna de agua.
- La turbulencia impulsada por el zooplancton tiene el potencial de impactar los ciclos biogeoquímicos del océano.
- Los hallazgos desafían las suposiciones anteriores sobre las limitaciones de escala de la turbulencia generada biológicamente.
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