Elizabeth North and Raleigh Hood

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A partnership proposal technology transfer of a
larval dispersal model
Elizabeth North and Raleigh Hood UMCES Horn Point
Laboratory
Research funded by NOAA Chesapeake Bay Studies
Program
http//seawifs.gsfc.nasa.gov/SEAWIFS/
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Presentation outline
Objective
Larval transport model description, accuracy,
and status
Next steps
3
Presentation outline
Objective
Larval transport model description, accuracy,
and status
Next steps
4
Objective
The objective of this project is to enhance the
DNR-funded larval dispersal model and transfer
the technology by creating two open-source models
suitable for inclusion in the NOS Partnership
Project and for posting on the Chesapeake
Community Modeling Program web page
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T. Gross
Li Zhong
DNR project predict population dispersal of
native and non-native oysters in Chesapeake Bay
Circulation models
Juvenile/adult population dynamics model (by
Christman and Volstad)
Larval transport model
Settlement at each oyster bar
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Presentation outline
Objective
Larval transport model description, accuracy,
and status
Next steps
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Particle Tracking Model

• Run with hydrodynamic model output from finite
• element (QUODDY) and curvilinear models (ROMS)

• External (10 min) and internal (30 s) time steps
  with
• 4th-order Runge Kutta calculations in time

• Water column profile
• tension spline interpolation
• scheme in space

• Advection based
• on current speeds
• in the x-, y-, and z-
• directions

• Random
• displacement
• model for sub-grid
• scale turbulence

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Initialize Model
Larval Transport Model Structure
Define variables
Read-in particle start locations
Internal Time Step
Read-in oyster bar locations
Advection
Read-in initial hydro data
Turbulence
External Time Step
Behavior
Read-in hydro data
Update particle location
Read-in hydro data
Boundary conditions
Settlement or mortality
Read-in hydro data
Print
End
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Initialize Model
Larval Transport Model Structure
Define variables
Read-in particle start locations
Internal Time Step
Read-in oyster bar locations
Advection
Read-in initial hydro data
Turbulence
External Time Step
Behavior
Read-in hydro data
Update particle location
Read-in hydro data
Boundary conditions
Settlement or mortality
Read-in hydro data
Print
End
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Water column profile interpolation method
Depth
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Water column profile interpolation method
Depth
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Water column profile interpolation method
Current speed
Depth
Tension Spline TSPACK by RJ Renka (linear
interpolation if convergence problems)
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Estimate current velocities at particle location
with output from circulation model
Depth
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Calculate distance and direction of particle
motion based on advection
Depth
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Simulate turbulence by calculating a random
kick proportional to turbulence in the
circulation model
Depth
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Calculate direction and distance of movement
based on behavior
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Particle movement during time step is
Advection Turbulence Behavior
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Calculate new location
Particle movement during time step is
Advection Turbulence Behavior
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Initialize Model
Larval Transport Model Structure
Define variables
Read-in particle start locations
Internal Time Step
Read-in oyster bar locations
Advection
Read-in initial hydro data
Turbulence
External Time Step
Behavior
Read-in hydro data
Update particle location
Read-in hydro data
Boundary conditions
Settlement or mortality
Read-in hydro data
Print
End
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Oyster larvae behavior
Oyster larvae swimming speed increase with
development Crassostrea virginica 0.8
3.1 mm s-1 (Hidu and Haskin 1978,
Mann and Rainer 1990), ongoing lab studies
C. ariakensis similar to C. virginica
Potential swimming behaviors Tidally
timed vertical migration (up during flood, down
during ebb)
Diurnal vertical migration (down during day)
Bottom oriented (remain near-bottom) C.
ariakensis Aggregate along halocline C.
virginica
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Behavior
Day
Night
Aggregate above halocline
Day
Night
Bottom oriented
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Stage-based application of behavior models
Veliger stage Aggregate above halocline
Competent to settle Bottom oriented
behavior Search for suitable substrate
Early-stage larvae Passive transport
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Initialize Model
Larval Transport Model Structure
Define variables
Read-in particle start locations
Internal Time Step
Read-in oyster bar locations
Advection
Read-in initial hydro data
Turbulence
External Time Step
Behavior
Read-in hydro data
Update particle location
Read-in hydro data
Boundary conditions
Settlement or mortality
Read-in hydro data
Print
End
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Boundary conditions particle reflect off
boundaries
Horizontal
Vertical
ROMS
QUODDY
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Initialize Model
Larval Transport Model Structure
Define variables
Read-in particle start locations
Internal Time Step
Read-in oyster bar locations
Advection
Read-in initial hydro data
Turbulence
External Time Step
Behavior
Read-in hydro data
Update particle location
Read-in hydro data
Boundary conditions
Settlement or mortality
Read-in hydro data
Print
End
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Oyster larvae settlement
Outside suitable habitat continue swimming
Crossings method
Inside settle
MD DNR Bay Bottom Survey 1974 - 1983
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Oyster larvae mortality
Mortality if particle doesnt settle by end of
pediveliger stage Mortality if particle remains
in waters of stressful salinity and/or
temperature for a given period of time
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Presentation outline
Objective
Larval transport model description, accuracy,
and status
Next steps
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Particle movement due to advection should match
hydrodynamic model predictions

• Calculate displacement of water parcel using
• Current velocities from model
• Particle locations
• Displacement values should be comparable if
  particle advection is being calculated correctly

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Animation
Particles
Mean location of particles
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particle start location
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particle start location
Mean particle location
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particle start location
Mean particle location
current velocity location
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North-south surface current velocities at fixed
location
From hydrodynamic model output
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North-south surface current velocities at fixed
location

• Fit 4th order polynomials
• Integrated area under curve to calculate
  displacement

Procedure
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North-south surface current velocities at fixed
location
2.94
2.56
-4.42
-5.70 km

• Fit 4th order polynomials
• Integrated area under curve to calculate
  displacement

Procedure
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Neutrally-buoyant particle displacement
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Neutrally-buoyant particle displacement
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Neutrally-buoyant particle displacement
-5.10 km
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Neutrally-buoyant particle displacement
2.88
-5.10 km
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Neutrally-buoyant particle displacement
2.88
-5.10 km
-3.92
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Neutrally-buoyant particle displacement
2.88
2.53
-5.10 km
-3.92
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Particle displacement corresponds to water
displacement
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Presentation outline
Objective
Larval transport model description, accuracy,
and status
Next steps
45
Initialize Model
Larval Transport Model Structure
Define variables
Read-in particle start locations
Internal Time Step
Read-in oyster bar locations
Advection
Read-in initial hydro data
Turbulence
External Time Step
Behavior
Read-in hydro data
Update particle location
Read-in hydro data
Boundary conditions
Settlement or mortality
Read-in hydro data
Print
End
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Initialize Model
Larval Transport Model Structure
Define variables
Read-in particle start locations
Internal Time Step
Read-in oyster bar locations
Advection
Read-in initial hydro data
Turbulence
External Time Step
Behavior
Read-in hydro data
Update particle location
Read-in hydro data
Boundary conditions
Settlement or mortality
Read-in hydro data
Print
End
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Example of larval transport model output
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Example of larval transport model output
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Does behavior change spatial patterns in
settlement?
Passive
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Passive
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Crassostrea virginica
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Crassostrea ariakensis
Larval behavior affects spatial patterns in
settlement
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Presentation outline
Objective
Larval transport model description, accuracy,
and status report
Next steps
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Next Steps

• I. Fortran Model
• Finish implementation of larval transport model
• Optimize Fortran model for speed
• Finish Fortran model Users Manual
• II. C Model
• Recode larval transport model into C
• Add C components to the Chesapeake Bay Oyster
  
• Decision Support Tool
• Write C model Users Manual
• III. Dissemination
• Post both larval transport models and Users
  Manuals
• on CCMP web page

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Acknowledgements
Modeling dispersal of Crassostrea ariakensis
oyster larvae in Chesapeake Bay
Elizabeth North, Raleigh Hood, Ming Li, Liejun
Zhong UMCES Horn Point Laboratory
Tom Gross Chesapeake Research Consortium NOAA/NOS/
Coast Survey
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Sub-grid scale turbulent motion
Random Displacement Model
zn1 zn K'(zn)dt R 2r-1 Kz 0.5K'(zn)dt
dt 1/2
where z particle vertical location K
vertical diffusivity K' dK/dz dt time
step of RDM 1 sec R is a random process, with
mean 0 and standard deviation r
Visser 1997
When K 0, random displacement model random
walk model
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Numerical dye release with a random walk model
(m)
Salinity (psu)
Particles
Eulerian tracer (dye)
Current velocity vectors
North, Hood, Chao, Sanford. in review. Journal of
Marine Systems
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Numerical dye release with random displacement
model
(m)
Salinity (psu)
Particles
Eulerian tracer (dye)
Current velocity vectors
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Well Mixed Condition Tests
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Well Mixed Condition Tests
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Well Mixed Condition Tests