Modeling Oyster Larvae Dispersal

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Modeling Oyster Larvae Dispersal In Chesapeake
Bay
Elizabeth North, Raleigh Hood, Ming Li, Liejung
Zhong University of Maryland Center for
Environmental Science Horn Point Laboratory, USA
Tom Gross Chesapeake Research Consortium NOAA/NOS/
Coast Survey Development Laboratory, USA
Funded by Maryland Department of Natural Resources
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• Objectives
• Determine potential distance and rate of
• native and Asian oyster larvae dispersal in
• Chesapeake Bay

• Quantify uncertainty in dispersal estimates

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• Methods
• Build stand-alone particle-tracking model that
• runs with output from two circulation models

• Parameterize particle behavior with laboratory
• studies of native and Asian oyster larvae
  (Drs.
• Newell, Kennedy, Manuel, Tamburri, Luckenbach,
  
• Brietburg, others?)

• Run particle-tracking model with output from
• different Chesapeake Bay hydrodynamic
• models that have similar forcing conditions

• Compare estimates of larval dispersal derived
• from each hydrodynamic model to quantify
• uncertainty in model results

• Link to demographic model

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• Larval Transport Model
• I. Circulation Models
• A. ROMS
• B. QUODDY
• C. Physical Forcing
• II. Particle Tracking Model
• A. Advection
• B. Turbulence
• C. Behavior
• a. swimming
• b. settlement
• D. Mortality

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• Larval Transport Model
• I. Circulation Models
• A. ROMS
• B. QUODDY
• C. Physical Forcing
• II. Particle Tracking Model
• A. Advection
• B. Turbulence
• C. Behavior
• a. swimming
• b. settlement
• D. Mortality

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• Circulation Models
• Regional Ocean Modeling System (ROMS)
• QUODDY (Dartmouth College circulation model)

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Regional Ocean Modeling System (ROMS)

• 3-D curvilinear model
• Grid spacing about 1 km
• 20 vertical layers
• High resolution resolves
• deep channel

Horizontal grid system
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QUODDY
3D finite element model15 Sigma LevelsMY2.5
Turbulence 20,987 Elements11,853 Nodes
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Physical Forcing freshwater flow and wind
1995 1996 1997 1998 1999
dry
wet
dry
ave
wet
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Physical Forcing constructing 20-yr time series
wet
dry
uniform
1998
1999
1 2 3 4 5 6 7 8 9 10 . . . 20
1999
1997
1995
1997
1996
1996
1996
1995
1997
1995
1999
1998
1998
1996
1996
1996
1995
1997
1997
1995
1998
1995
1999
1999
1999
1997
1998
1998
. . .
. . .
. . .
1996
1995
1995
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• Larval Transport Model
• I. Circulation Models
• A. ROMS
• B. QUODDY
• C. Physical Forcing
• II. Particle Tracking Model
• A. Advection
• B. Turbulence
• C. Behavior
• a. swimming
• b. settlement
• D. Mortality

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Particle Tracking Model

• Water column profile tension spline
• interpolation scheme

• Run with hydrodynamic model output from
• both finite element and curvilinear models

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

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

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Behavior
Swimming speed increase with development
C. virginica 0.8 3.1 mm s-1 (Hidu and
Haskin 1978, Mann and Rainer 1990),
current lab studies C. ariakensis
current lab studies
Swimming behavior Potential cues
salinity, temperature, tidal currents, light,
halocline, DO
Developmental shift in behavior Results
of current lab studies for both C. a. and C. v.
and literature on C. v.
Example animation . . .
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Behavior (cont.)
Settlement behavior Potential cues
bottom type, temperature, tidal currents,
light, DO, concentration of living
oysters, salinity Results of current
lab studies for both C. a. and C. v.
and literature on C. v.
MD DNR Bay Bottom Survey 1974 - 1983
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Mortality
Physiological tolerances Physical cues
temperature, salinity, DO Results of
current lab studies for both C. a. and C. v.
and literature on C. v. Everything
else (!!) predation, poor nutrition, etc.
Several levels of constant mortality
Literature-derived values
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Link to Demographic Model
Input to larval transport model from demographic
model -- zygote production (number of
fertilized eggs per unit time) at each
location Output to demographic model from larval
transport model -- number of settling
larvae (spat) at each location