Download Digital Quadrat Analysis of Percent Algal Cover on Conesus

Digital Analysis of Quadrats to
Determine Percent Cover of
Metaphyton in Conesus Lake, NY
Alternate method for accurate
determination of percent cover
Michael Pagano
Dr. Sid Bosch
State University of New York at Geneseo
Summer 2003
Problem at Conesus LakeMetaphyton
• Correlation between growth of metaphyton with
nutrient loading from streams
Problem with determination of
percent cover
• Metaphyton biomass
hard to estimate
• Entangled in Milfoil,
can’t separate
• Percent Cover best
estimation
Traditional Method
• Visual determination
of cover
• Stationed off side of
boat
• Dependant on
researcher
• Lack of precision
Alternate Method
• Construction of new quadrat (.5x.5m) to enable
use of digital camera to capture image of algae
• Camera mounted Tri-pod
• Polarized lens used to reduce glare
Alternate Method
• Digital Pictures
(3.2mp) uploaded
onto computer
• Images enhanced
using Kodak Photo
Enhancer
Alternate Method
• Images then analyzed using Image
J to determine percent cover
Percent Cover=
Total Cover
Total Area
Results
ANOVA p<0.05
2003 Metaphyton
percent cover
120
100
80
60
40
20
Error bars indicate one standard deviation above and below mean
Bars above represent results of Tukey’s Statistical Analysis
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Results
80
32
Mean Percent Metaphton cover
70
35
24
60
25
50
37
40
40
15
14
30
30
2002
6.5
2003
27
20
2001
29
21
7
10
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Graywood 2003, Cottonwood 2002, Sandpoint 2002, & Sutton 2002 not used due to sampling error which
included date and condition of weed beds. Numbers above bars represent one standard deviation
Results
P=0.06
70
Percent Cover Metaphyton
2
R = 0.8806
60
50
40
30
20
10
0
0.00
5.00
10.00
15.00
20.00
Loading SRP (6/1-8/31, 2003) Kg
No loading data for McPherson, Graywood Gully not used for statistical purposes
because unrepresentative sampling period; Error Bars (+/- 1 S.D.) to small to see
Metaphyton Cover Determination
• Is Digital Analysis more accurate than traditional
visual estimation?
Results
• Coefficient of Variation
– CV= S.D./Mean
– Measure of Relative Variability
Organism
Coefficient of Variation
Plankton
0.70
Benthic Organisms (grab sample)
0.40
Benthic Organisms
(Surber sampler, counts)
0.60
Benthic Organisms
(Surber sampler, biomass)
0.80
Terrestrial Organisms
(Roadside Counts)
0.80
Shellfish
0.40
Mean C.V.
Alternate Method
2001= 0.883319 +0.385
2002= 0.979605 + 0.110
2003= 0.397958 + 0.137
1.2
1
2001
0.8
2002
0.6
2003
0.4
0.2
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Coefficient of Variation
1.4
Conclusions
• No consistent trends seen between weed beds
• Correlation seen between metaphyton percent
cover and summer SRP loading, 2003
• Alternate method more accurate for
determination of percent cover, but more
replicates needed
Special Thanks
• Dr. Sid Bosch,
Mentor and Project
Advisor
• Megan Mongiovi,
Jamie Romieser,
Evan Zynda,
Student
Researchers
• SUNY Geneseo
Biology