Title :

Copepods in turbulence: laboratory velocity and acceleration studies using high speed cameras

Author(s) :

Le Quiniou, Clotilde [Auteur]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Université du Littoral Côte d'Opale [ULCO]
Schmitt, François G [Auteur]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Huang, Yongxiang [Auteur]
Xiamen University
Calzavarini (Admin), Enrico [Auteur]
Unité de Mécanique de Lille - ULR 7512 [UML]
Laboratoire de Mécanique de Lille - FRE 3723 [LML]
Souissi, Sami [Auteur]
Université de Lille
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]

Conference title :

EGU General Assembly 2021

City :

Vienne (AUT)

Country :

Autriche

Start date of the conference :

2021-04-19

Publication date :

2021-03-03

HAL domain(s) :

Planète et Univers [physics]

English abstract : [en]

Planktonic copepods are tiny crustaceans, with a typical size of the order of mm, living in suspension in marine or freshwaters during their entire life cycle. They have swimming and jumping abilities and are known to be ...
Show more >Planktonic copepods are tiny crustaceans, with a typical size of the order of mm, living in suspension in marine or freshwaters during their entire life cycle. They have swimming and jumping abilities and are known to be well adapted to their turbulent environment. Turbulence is known to increase their contact rate and feeding flux. However too intense turbulence is believed to have a negative effect so that a qualitative bell-shape is classically invoked to represent the contact rate of copepods versus turbulence intensity. In this framework, the objective of this work is to quantify the influence of ambient turbulence on copepod's behavior, using trajectory analysis. In this work, the motions of copepods were filmed using an infrared high-speed camera (1000 fps) in a turbulent environment, in the dark to avoid phototropism. The custom-made experimental set-up has been built-up in order to obtain in a central zone an isotropic and homogeneous turbulence representative of the natural environment. The flow was characterized with different tracer sizes at different turbulence intensities. Copepods are filmed and the trajectories are extracted using signal processing routines. The instantaneous velocity, tangential and centripetal accelerations, and the local curvature are extracted for each trajectory. Their pdfs are computed, as well as different statistical moments: these indicators are studied at varying the turbulence intensity level (Reynolds number). Particles of different sizes (100 and 600 microns of mean diameters) and dead copepods are compared to living copepods statistics. This strategy allows to precisely characterize the copepods behavioral activity in relation with ambient turbulence. Ecological interpretations are drawn from the experimental results.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

Collections :

• Laboratoire d'Océanologie et de Géosciences (LOG) - UMR 8187

Source :

Harvested from HAL