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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. 23-26 2006
Project Overview
Background:
•Relationship between pigment concentration and
light reflectance from leaves
•Light reflectance from leaves is modulated by
stressor factors
Hypothesis:
•The light reflected from plants can be used
as a surrogate variable to determine salinity
and metal concentration in the sediments.
Overall:
Objectives
- 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
Field Work
Sampling (May 2 – July 20)
– Leaf samples
– Sediment samples
– Leaf reflectance (field data)
– Canopy reflectance (field data)
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]
Salinity in the sediment
12
8
6
4
2
Site
T
C
A
D
B
D
KP
BB
BA
0
KG
salinity
10
Contaminants in the sediment in May
and August
Chromium
Copper
800
800
600
Cu [mg/kg]
500
400
300
Mercury
T
C
A
D
B
D
site
C
T
D
A
D
B
KP
BB
BA
0
KG
05/02
0
KP
05/02
date
date
200
BB
100
08/22
400
BA
08/22
200
600
KG
Cr [mg/kg]
700
08/22
date
Zinc
CT
DA
DB
KP
BB
05/02
BA
Lead
100
90
80
70
60
50
40
30
20
10
0
KG
Hg [mg/kg]
sites
site
05/02
0
site
C
T
D
A
D
B
KP
BB
BA
KG
0
500
site
C
T
05/02
D
A
1000
date
D
B
date
08/22
1000
KP
2000
1500
BB
08/22
2000
BA
3000
KG
Pb [mg/kg]
4000
Zn [mg/kg]
2500
5000
Metal-metal relationship in the sediment
Cd
Cd
Correlation
Sig.
Cr
Pb
Zn
0.869
0.387
0.085
0.816
0.833
-0.298
0.991
0.011
0.391
0.856
0.025
0.020
0.517
0.000
1
0.131
-0.039
0.964
0.861
-0.369
0.880
0.779
0.934
0.000
0.013
0.416
0.009
1
0.915
0.175
0.492
-0.168
0.446
0.004
0.707
0.262
0.718
0.316
1
0.005
0.322
-0.171
0.162
0.991
0.482
0.714
0.729
1
0.924
-0.318
0.852
0.003
0.487
0.015
1
-0.332
0.889
0.467
0.007
1
-0.259
.
.
.
.
.
Correlation
Sig.
Zn
Ni
Correlation
Sig.
Pb
Hg
Correlation
Sig.
Ni
Fe
Correlation
Sig.
Hg
Cu
Correlation
Sig.
Fe
.
Correlation
Sig.
Cu
1
Cr
.
0.575
Correlation
Sig.
1
.
Cr, Cd, Hg and Zn tend to coexist in the sediment
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
Site comparison based on sediment toxicity
80
70
50
40
30
20
10
Site
T
C
A
D
B
D
KP
BB
BA
0
KG
toxicity
60
Spectral data analysis
Vegetation Indices
-NDVI:
ρNIR – ρRED
ρNIR + ρRED
-Greenness Ratio:
ρGREEN
ρRED
-Red Edge Inflection
Point (REIP)
PeakFit v.4.12
NDVI values for Canopies Arranged by Date
1.00
0.90
KG
BA
0.70
BB
0.60
KP
NDVI
0.80
DB
0.50
DA
0.40
CT
0.30
0.20
0.10
0.00
5/2
5/9
5/23
5/30
6/6
6/16
Date
6/29
7/7
7/20
Salinity in the sediment
Site comparison based on sediment toxicity
80
12
70
10
salinity
50
40
30
20
8
6
4
Site
Site
T
C
A
D
B
D
KP
BB
BA
KG
T
C
A
D
D
B
0
KP
0
BB
2
BA
10
KG
toxicity
60
Metal in the leaves
Zinc
Lead
3.00
80
BA
60
40
BB
s
site
KP
0616
0531
CT
0522
0509
0707
0629
0606
0.50
KP
0.00
DB
Copper
0719
DA
1.00
BB
0
DB
1.50
BA
s
si te
20
KG
DA
CT
date
0502
0509
0522
0502
50.00
30.00
KG
20.00
BA
BB
10.00
s
site
KP
0.00
DB
DA
CT
0502
0509
0522
0531
0606
0616
date
0629
0707
0719
Cu [mg/kg]
40.00
0531
0606
0616
date
0629
0707
0719
Pb [mg/kg]
2.50
2.00
Zn [mg/kg]
KG
120
100
Leaf Red Edge Inflection Point versus
sediment toxicity
location of the inflection point [nm]
725
724
723
722
721
720
719
718
leaf
717
716
715
714
713
712
711
710
0
10
20
30
40
50
toxicity
60
70
80
90
Canopy Red Edge Inflection Point
versus metal toxicity
canopy
location of the inflection point [nm]
732
731
R = 0.62
730
729
728
727
726
725
0
10
20
30
toxicity50
40
60
70
80
90
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.
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
Acknowledgements
The Meadowlands Environmental Research Institute
-Dr. Jin Young Shin
-Yefim Levinsky
-So Yeon
Acknowledgements
The Meadowlands Environmental Research Institute
-Dr. Jin Young Shin
-Yefim Levinsky
-So Yeon