PREDICTION OF HYPERSPECTRAL IOPs ON THE WEST FLORIDA SHELF

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PREDICTION OF HYPERSPECTRAL IOPs ON THE WEST
FLORIDA SHELF

• W. Paul Bissett
• Florida Environmental Research Institute
• John J. Walsh, Dwight A. Dieterle, and Jason
  Jolliff
• Department of Marine Science, University of South
  Florida

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Contributors to the Presentation

• This work presented here is part of a larger
  program to predict Inherent and Apparent Optical
  Properties (IOPs and AOPs) in the coastal ocean
  (ONR HyCODE program) and the Ecology of Harmful
  Algal Blooms (ONR/NSF/NOAA/EPA ECOHAB).
• Field data provided by
• R. Arnone, Naval Research Laboratory-Stennis
  Space Center
• T. Hopkins T. Sutton, University of South
  Florida
• G. Kirkpatrick, Mote Marine Laboratory
• S. Lohrenz, University of Southern Mississippi
• R. Weisberg, University of South Florida

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Red Tides on the West Florida Shelf
Gymnodinium breve
Breve-toxin causes fish kills and respiratory
ailments.
In 1996, an extended G. breve bloom was
implicated in the deaths of 149 manatees off west
coast of Florida.
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West Florida Shelf (WFS)
ECOHAB Control Volume
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EcoSim 1.0 Review

• four functional groups of phytoplankton
• heterotrophic and chemolithic bacteria
• two forms of dissolved organic carbon and
  nitrogen
• spectral light (5 nm resolution)
• differential (non-redfield) carbon and nitrogen
  cycling
• grazing, sinking, and excretion
• particulate remineralization
• nitrification and nitrogen-fixation
• surface gas exchange
• colored dissolved organic carbon cycling

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EcoSim 2.0 Formulation
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EcoSim 2.0 Formulation

• Transition from 1- to 3-dimensional coding.
• Addition of phosphorous, silica, and iron as
  limiting nutrients.
• All POM and DOM state variables are independent,
  allowing for non-Redfield stoichiometry.
• Addition of 3 new phytoplankton functional
  groups.
• Coastal diatoms, coastal dinoflagellates, and G.
  breve.
• Living particulate detritus absorption addition
  to phytoplankton inherent optical properties
  (IOPs).
• New CDOM cycling dynamics.
• Color is now conserved and assumed to be
  recalcitrant to bacterial remediation.
• Bottom boundary claims all fluxing particulate
  material.
• Sediment chlorophyll a can be as high as
  overlying waters.

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EcoSim Light Model
For each depth interval
light attenuation c(l,t) a(l,t) b(l,t)
absorption a(l,t) awater(l) aphyto(l)
aCDOM(l) ased(l)
scattering b(l,t) bwater(l) bphyto(l)
bCDOM(l) bsed(l)
backscattering bb(l,t) bb,water(l)
bb,phyto(l) bb,CDOM(l) bb,sed(l)
geometric structure of light md(l) fxnb(l,t),c
(l ,t), m0(l)
diffuse light attenuation Kd(l) a(l,t) bb(l
,t)/md(l)
water leaving radiance to a satellite Lu(l)
fxna(l,t),b(l ,t), bb(l ,t),Ed(l,t), md(l),
md(l), mu(l)
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West Florida Shelf (WFS)
Florida Middle Grounds
ECOHAB Control Volume
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Aerial Photograph of TrichodesmiumSt. Petersburg
Beach, FL July 7, 1995
Trichodesmium Bloom
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Location of G. breve October 2000
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Location of G. breve October 2000
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Mooring Locations on WFSOcean Circulation Group
(http//ocg6.marine.usf.edu/) R. Weisberg USF
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September 1998
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October 1998
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November 1998
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December 1998
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2-Dimensional Representation of WFS
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High Resolution Sampler (HRS) T. Hopkins T.
Sutton (USF) September 22-23, 1998
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Mote Marine EcoHAB CruiseG. Kirkpatrick
September 22, 1998
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EcoSim 2.0 Nutrients (Day 270)
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EcoSim 2.0 Phytoplankton Carbon (Day 270)
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EcoSim 2.0 Chlorophyll a (Day 270)
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EcoSim Phytoplankton CN Ratio (Day 270)
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EcoSim 2.0 Particulate and CDM Absorption412 and
487 nm (Day 270)
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EcoSim 2.0 Absorption and Diffuse Attenuation412
and 487 nm (Day 270)
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EcoSim 2.0Predicted Particulate Absorption
(Day 270)
9 m, near-shore Chl a 1.34 mg m-3
2 m, near-shore Chl a 1.61 mg m-3 Chl a 0.95
mg m-3 (gt3 micron)
Measured Absorption aph(l) S. Lohrenz (USM)
October 1998
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EcoSim 2.0Predicted Particulate Absorption
(Day 270)
1 m, off-shore Chl a 0.18 mg m-3
3 m, off-shore Chl a 0.14 mg m-3 Chl a 0.14
mg m-3 (gt3 micron)
Measured Absorption aph(l) S. Lohrenz (USM)
October 1998
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EcoSim 2.0Predicted Particulate Absorption
(Day 270)
39 m, off-shore Chl a 0.46 mg m-3
68 m, off-shore Chl a 0.45 mg m-3 Chl a 0.38
mg m-3 (gt3 micron)
Measured Absorption aph(l) S. Lohrenz (USM)
October 1998
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EcoHAB Process CruiseG. Kirkpatrick (MML)
October 5 12, 1998
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SeaWiFS Kd(490) CalculationOctober 6, 1998 B.
Arnone (NRL-Stennis)
m-1
5.00
1.25
0.31
0.08
0.02
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SeaWiFS (SeaBAM) Chlorophyll aOctober 6, 1998 B.
Arnone (NRL-Stennis)
m-1
45.0
7.61
1.32
0.23
0.04
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EcoSim 2.0 Nutrients (Day 306)
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EcoSim 2.0 Phytoplankton Carbon (Day 306)
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EcoSim 2.0 Chlorophyll a (Day 306)
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EcoSim 2.0 Absorption and Diffuse Attenuation412
and 487 nm (Day 306)
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Mote Marine EcoHAB CruiseG. Kirkpatrick November
23, 1998
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EcoSim 2.0 Phytoplankton Carbon (Day 324)
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EcoSim 2.0 Chlorophyll a (Day 324)
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EcoSim 2.0 Absorption and Diffuse Attenuation412
and 487 nm (Day 324)
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EcoHAB Process CruiseG. Kirkpatrick November
16-19, 1998
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EcoSim 2.0 Phytoplankton Carbon (Day 324)Reduced
Grazing Pressure on G. breve
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Summary

• EcoSim 2.0 appears to generate reasonable IOP
  predictions across the West Florida Shelf in
  1998.
• But freshwater fluxes are critical to near-shore
  predictions of IOPs.
• Reconstruction of phytoplankton absorption
  spectral from pigment specific absorption yields
  errors in the blue.
• G. breve populations are minimal at all times
  during the year, including Loop Current
  intrusions.
• Only way to get G. breve bloom is to increase
  nutrients without Si and reduce grazing.
• Nitrogen-fixation may yield excess N, but is
  phosphorous limited in shelf waters.

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Movies
Nutrients
Phytoplankton Carbon
Chlorophyll a
Particulate and CDM Absorption
Total Absorption and Diffuse Attenuation