Salinity and Sediment Contaminants and the Reflectance

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Salinity and Sediment Contaminants and the
Reflectance Green-upof Phragmites australis
Ildiko Pechmann Francisco Artigas
New Jersey Meadowlands Commission Meadowlands
Research Institute
9th Wetlands Watersheds Workshop Atlantic City,
NJ Oct. 23-26 2006
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Project Overview

• Background
• Relationship between pigment concentration and
  light reflectance from leaves
• Light reflectance from leaves is modulated by
  stressor factors

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• Hypothesis
• The light reflected from plants can be used as a
  surrogate variable to determine salinity and
  metal concentration in the sediments.

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Objectives
Overall
- Find if metal toxicity alters or modifies
chlorophyll content in a way that plants under
metal stress show differences in reflectance
Specific
- Measure salinity and metals at seven distinct
study sites
- Measure metal uptake by leaves over the growing
season
- Measure light reflectance from leaves and
canopies over the growing season
- Find if there is a relationship between metal
content in leaves and light reflectance
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Field Work

• Sampling (May 2 July 20)
• Leaf samples
• Sediment samples
• Leaf reflectance (field data)
• Canopy reflectance (field data)

DA,DB
BA,BB
CT
KP, KG
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Parameters measured
Test plant Phragmites australis

• Leaves
• metal concentration (Cd, Cr, Cu, Fe, Hg, Ni, Pb,
  Zn)
• reflectance

• Canopy
• reflectance

• Sediment
• metal concentration (Cd, Cr, Cu, Fe, Hg, Ni, Pb,
  Zn)
• Salinity ppt

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Contaminants in the sediment in May and August
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Metal-metal relationship in the sediment
Cd Cr Cu Fe Hg Ni Pb Zn
Cd Correlation 1 0.869 0.387 0.085 0.816 0.833 -0.298 0.991
Cd Sig. . 0.011 0.391 0.856 0.025 0.020 0.517 0.000
Cr Correlation   1 0.131 -0.039 0.964 0.861 -0.369 0.880
Cr Sig.   . 0.779 0.934 0.000 0.013 0.416 0.009
Cu Correlation     1 0.915 0.175 0.492 -0.168 0.446
Cu Sig.     . 0.004 0.707 0.262 0.718 0.316
Fe Correlation       1 0.005 0.322 -0.171 0.162
Fe Sig.       . 0.991 0.482 0.714 0.729
Hg Correlation         1 0.924 -0.318 0.852
Hg Sig.         . 0.003 0.487 0.015
Ni Correlation           1 -0.332 0.889
Ni Sig.           . 0.467 0.007
Pb Correlation             1 -0.259
Pb Sig.             . 0.575
Zn Correlation               1
Zn Sig.               .
Cr, Cd, Hg and Zn tend to coexist in the sediment
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Calculating Toxic Units
- Metal concentrations in sediment were
transformed in toxic units (TU) according to the
E-RM (Effect Range Median) values (LongMorgan,
1990)
- Toxicity ranged between 0 and 80 TU depending
on how much the metal concentrations exceeded the
E-RM criteria.
- Summary of TUs were calculated for each
sampling site and related to reflectance
parameters
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Spectral data analysis
Vegetation Indices
-NDVI ?NIR ?RED ?NIR ?RED
-Greenness Ratio ?GREEN ?RED
-Red Edge Inflection Point (REIP)
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Metal in the leaves
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Leaf Red Edge Inflection Point versus sediment
toxicity
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Canopy Red Edge Inflection Point versus metal
toxicity
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Conclusion

• The most saline site CT - showed a delayed
  green-up

• The most contaminated sites DA DB - showed an
  early flowering

• Our results indicated that there were no changes
  in the leaf reflectance due to the metal toxicity

• However the canopy reflectance measurements
  showed relationship with sediment toxicity.

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Future Research

• Continue to use remote sensors to classify stress
  levels
• in Phragmites communities.

• Focus on differences in light reflectance due to
  the
• plant architecture and canopy texture as they
  relate
• to bio-geological conditions in the sediment.

• Also use remote sensors to look at phenology
  (i.e.
• flowering and green-up timing) to identify
• Phragmites stands under heavy metal stress

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Acknowledgements

• The Meadowlands Environmental Research Institute
• Dr. Jin Young Shin
• Yefim Levinsky
• So Yeon

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Acknowledgements

• The Meadowlands Environmental Research Institute
• Dr. Jin Young Shin
• Yefim Levinsky
• So Yeon