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    Tank measurements characterizing turbulence for larvae experiments conducted at Woods Hole Oceanographic Institution in 2011 (Larvae in turbulence project)
    
  
  
    
    

Tank measurements characterizing turbulence for larvae experiments conducted at Woods Hole Oceanographic Institution in 2011 (Larvae in turbulence project)

Website: https://www.bco-dmo.org/dataset/561097
Data Type: experimental
Version: 2015-06-08

Project
» Larval Response to Turbulence During Dispersal and Settlement (Larvae in turbulence)
ContributorsAffiliationRole
Mullineaux, LaurenWoods Hole Oceanographic Institution (WHOI)Principal Investigator
Helfrich, Karl R.Woods Hole Oceanographic Institution (WHOI)Co-Principal Investigator
Wheeler, JeanetteWoods Hole Oceanographic Institution (WHOI)Student, Contact
Copley, NancyWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager


Dataset Description

Data taken measuring grid-stirred tank turbulence under a range of forcing frequencies at amplitude 5 cm. Tank is described in Wheeler et al. (2013).  Turbulence properties calculated from velocity vectors estimated from PIV analysis (an analogous PIV analysis described in Wheeler et al. 2013). Measurements were made by K. Helfrich in Summer 2009.

Relevant References:

Wheeler J.D., Helfrich K.R., Anderson E.J., McGann B., Staats P., Wargula A.E., Wilt K., Mullineaux L.S. (2013) Upward swimming of competent oyster larvae Crassostrea virginica persists in highly turbulent flow as detected by PIV flow subtraction. Mar Ecol Prog Ser 488, 171-185.

Wheeler J.D., Helfrich K.R., Anderson E.J., Mullineaux L.S. (2015) Isolating the hydrodynamic triggers of the dive response in eastern oyster larvae. Limnol Oceanogr, (doi:10.1002/lno.10098)


Processing Description

PIV velocity vectors have been used to compute root mean square velocities, integral length scales (as per Tennekes and Lumley 1972), energy dissipation rates (as per Doron et al. 2001), and Kolmogorov length scales.


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Parameters

ParameterDescriptionUnits
dial_numtank turbulence dial setting unitless
freqoscillation frequency of double grid at amplitude 5 cm Hz
energy_dissipationenergy dissipation rate; estimated using equation from Doron et al. 2001 cm^2/s^3
vel_Urmshorizontal root mean square velocity cm/s
vel_Wrmsvertical root mean square velocity cm/s
Kolmog_lenKolmogorov length scale of turbulent flow; using a kinematic viscosity of 0.01 cm^2/s cm
integral_xhorizontal integral length scale; estimated using Tennekes and Lumley cm
integral_zvertical integral length scale; estimated using Tennekes and Lumley cm


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Instruments

Dataset-specific Instrument Name
Generic Instrument Name
Camera
Dataset-specific Description
high-speed monochrome camera (Photron Fastcam SA3) and a pulsed near-infrared laser (Oxford Lasers, Firefly 300 W, 1000 Hz, 808 nm) for particle image velocimetry (PIV) analysis
Generic Instrument Description
All types of photographic equipment including stills, video, film and digital systems.


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Deployments

lab_Mullineaux_2011

Website
Platform
WHOI
Start Date
2011-06-01
End Date
2012-08-31
Description
Larval oysters in turbulence experiments


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Project Information

Larval Response to Turbulence During Dispersal and Settlement (Larvae in turbulence)

Coverage: Laboratory studies at Woods Hole Oceanographic Institution


Description from NSF award abstract:
The planktonic larval stage of benthic marine invertebrates provides a mechanism for exchange of individuals between remote populations. Dispersal is affected by swimming behaviors, particularly those that alter the larva's vertical position in the water. Larvae of some species change their vertical positions in response to turbulence by ceasing to swim and sinking downward (diving). By doing so, they can alter their horizontal transport in currents and increase their supply to the seafloor. The main objectives of this study are to investigate behavioral responses of oyster (Crassostrea virginica) larvae to turbulence in the water column and at the seafloor, and to determine how these behaviors affect settlement. The investigators hypothesize that diving behavior enhances settlement into suitable habitat, even where mean bed shear stress is high. They expect that once larvae approach the bottom, they can take advantage of temporal and spatial refuges (such as turbulent lulls in the lee of roughness elements) to settle in otherwise harsh conditions. Investigating larval responses to turbulence is a challenge because it requires simultaneous measurement of time-variant flows and larval behaviors. The investigators will modify a conventional particle image velocimetry (PIV) approach so it can be used to track larval motions and fluid velocities simultaneously. PIV provides information on flow kinematics (e.g., rotation and strain rate) in the immediate vicinity of a larva, as well as bulk dissipation rates and measures of Taylor and integral length scales that likely influence larval acceleration. When these measurements are coupled with a larval trajectory, they provide a history of the fluid environment a larva experiences, and can be used to determine what characteristic of turbulence triggers the diving behavior. They also make it possible to calculate the bottom shear stress an individual larva experiences when it encounters the bottom and attempts to settle. The investigators will examine turbulence effects on larval behaviors in the water column using a grid-stirred tank. They will use a racetrack flume to test the hypothesis that larval settlement success depends on the frequency of lulls of sufficient duration for larval attachment.

Laboratory experiments will provide a mechanistic understanding of larval behavior that can be used in general theoretical models exploring how behavior influences dispersal and population connectivity. The quantified swimming responses of oysters are critical input for coupled bio-physical models of dispersal in the field. An understanding of larval behavior contributes to our ability to predict the effects of natural and anthropogenic perturbations (some of which are linked to global climate change) on benthic communities in coastal ecosystems where turbulence and habitat suitability vary spatially. This information is critical for informed decision making on shellfish management and design of marine reserves. The technique developed for simultaneous PIV and larval tracking will open new questions in larval ecology and be broadly applicable to studies of plankton interactions with turbulence.



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Funding

Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)

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This document is created by info v 4.1f 5 Oct 2018 from the content of the BCO-DMO metadata database.    2022-05-17  10:07:47