1. Salinity and Sediment Contaminants and the Reflectance & Green-up of Phragmites australis
Ildiko Pechmann & Francisco Artigas
New Jersey Meadowlands Commission – Meadowlands Research Institute
9th Wetlands & Watersheds Workshop
Atlantic City, NJ
Oct

2. Project Overview Background:
Relationship between pigment concentration and light reflectance from leaves
Light reflectance from leaves is modulated by stressor factors

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

4. Objectives Overall: Specific:
- 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

5. Field Work DA,DB BA,BB CT KP, KG Sampling (May 2 – July 20)
Leaf samples
Sediment samples
Leaf reflectance (field data)
Canopy reflectance (field data)
DA,DB
BA,BB CT
KP, KG

6. 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]

8. Contaminants in the sediment in May and August

9. Metal-metal relationship in the sedimentCd Cr Cu Fe Hg Ni Pb Zn
Correlation 1
0.869
0.387
0.085
0.816
0.833
-0.298
0.991
Sig. .
0.011
0.391
0.856
0.025
0.020
0.517
0.000
0.131
-0.039
0.964
0.861
-0.369
0.880
0.779
0.934
0.013
0.416
0.009
0.915
0.175
0.492
-0.168
0.446
0.004
0.707
0.262
0.718
0.316
0.005
0.322
-0.171
0.162
0.482
0.714
0.729
0.924
-0.318
0.852
0.003
0.487
0.015
-0.332
0.889
0.467
0.007
-0.259
0.575
Cr, Cd, Hg and Zn tend to coexist in the sediment

10. Calculating Toxic Units
- Metal concentrations in sediment were transformed in toxic units (TU) according to the E-RM (Effect Range Median) values (Long&Morgan, 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

12. Spectral data analysis
Vegetation Indices
PeakFit v.4.12
-NDVI:
ρNIR – ρRED
ρNIR + ρRED
-Greenness Ratio:
ρGREEN
ρRED
-Red Edge Inflection Point (REIP)

14. Metal in the leaves

15. Leaf Red Edge Inflection Point versus sediment toxicity

16. Canopy Red Edge Inflection Point versus metal toxicity

17. 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.

18. 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

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

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