Lagrangian description of 2 d marine larval dispersal kernels
Download
1 / 16

Lagrangian description of 2-D marine larval dispersal kernels - PowerPoint PPT Presentation


  • 447 Views
  • Uploaded on

Lagrangian description of 2-D marine larval dispersal kernels. Karen Pehrson Edwards, Jon Hare, Cisco Werner, Harvey Seim Ocean Sciences, Feb. 2006. Outline. Background: Dispersal Kernels Model Region: The South Atlantic Bight Methods: Lagrangian Particle Tracking

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Lagrangian description of 2-D marine larval dispersal kernels' - sandra_john


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Lagrangian description of 2 d marine larval dispersal kernels l.jpg

Lagrangian description of 2-D marine larval dispersal kernels

Karen Pehrson Edwards, Jon Hare, Cisco Werner, Harvey Seim

Ocean Sciences, Feb. 2006


Outline l.jpg
Outline kernels

  • Background: Dispersal Kernels

  • Model Region: The South Atlantic Bight

  • Methods: Lagrangian Particle Tracking

  • Results: Quantifying the dispersal kernels

  • Next steps

Provided by Harvey Walsh, NOAA Beaufort


Dispersal kernels l.jpg

1D dispersal kernel -Passive, Mean Flow- Diffusion kernels

Dispersal Kernels

  • A dispersal curve, or dispersal kernel (probability density function), the probability that a larva will settle at a given distance from its release location.

    Cowen et al. (2002)

  • Factors affecting dispersal include:

    • Physical factors:

      • Advection & diffusion

      • Intermittent/ episodic events,

      • interannual variability,

      • long-term modulations

    • Biological factors:

      • Spawning time & location

      • Larval behavior

      • Along-trajectory mortality

      • Larval condition and the ability to respond to cues for suitable habitat.

        Cowen et al. (2002), Mora & Sale (2002)

Provided by Harvey Walsh, NOAA Beaufort


Understanding larval dispersal provides important information about l.jpg
Understanding larval dispersal provides important information about:

  • Population connectivity

  • Population persistence or sustainability

  • Effectiveness and design of management strategies such as MPAs

    Cowen et al, 2002


Slide5 l.jpg
Question: what is the relative importance of the following factors on larval dispersal and population connectivity?

  • time of release,

  • location of release,

  • larval duration,

  • larval behavior, and

  • larval dispersion

  • Focusing on a case study in the South Atlantic Bight


The south atlantic bight l.jpg

Cape Hatteras factors on larval dispersal and population connectivity?

NC

SC

GA

Cape Canaveral

FL

The South Atlantic Bight

Gulf Stream


The south atlantic bight7 l.jpg
The South Atlantic Bight factors on larval dispersal and population connectivity?

Inner Shelf (<15-20m):

  • River runoff

  • Atmospheric fluxes and tides

Mid- Shelf (20-40m):

  • Winds

  • Tides and Gulf Stream

Outer- Shelf (>40m):

  • Gulf Stream

http://www.skio.peachnet.edu/

Lee et al. 1991


Methods lagrangian particle tracking model l.jpg
Methods: Lagrangian Particle Tracking Model factors on larval dispersal and population connectivity?

  • 3D long-term monthly mean circulation fields (Blanton et al., 2003)

  • Plus the M2 tide

  • and turbulent random kick (providing larval dispersion).

  • 300 particles released in each model run.


Results grnms dispersal l.jpg
Results: GRNMS Dispersal factors on larval dispersal and population connectivity?

  • Monthly releases

  • Mid-depth releases

  • 30d passive

  • Principal Component Analysis (PCA) defines the dispersal kernel.


Monthly mean dispersal from grnms l.jpg
Monthly Mean Dispersal from GRNMS factors on larval dispersal and population connectivity?



Larval behavior l.jpg
Larval Behavior importance:

Resulting mean dispersal for each behavior:

Simple Model Behaviors


Larval behavior13 l.jpg
Larval Behavior importance:

Dispersal for particles released at 60m isobath:

Mid-depth

Shallow

Deep


Physics l.jpg
Physics importance:

Tracks of drifters released at GRNMS

  • Model 2002-2004 to look at interannual variability


Modeling specific species l.jpg

www.martinreefs.com/pages/species_index/species_common.html importance:

Adult Black Sea Bass Species Occurrence

Hare et al., 1999

http://map.mapwise.com/safmc MARMAP survey

Modeling specific species


Dispersal in the sab l.jpg
Dispersal in the SAB importance:

  • Dominant factors: Time and Location of Release

    • with strong seasonal modulation

  • Behavioral Implications

    • Adult behavior (spawning time & location):

      • most important factor in quantifying dispersal with spawning in (apparently) retentive inner- to mid-shelf

    • Larval behavior: smaller effects possibly due to

      • Weak vertical structure on inner-shelf

      • Long-term (average) flow fields don’t account for transient features.


ad