digital analysis of quadrats to determine percent cover of metaphyton in conesus lake, ny

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 Lake- Metaphyton

• 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

Results2003 Metaphyton

0

20

40

60

80

100

120

perc

ent c

over

Error bars indicate one standard deviation above and below mean

Bars above represent results of Tukey’s Statistical Analysis

ANOVA p<0.05

Results

0

10

20

30

40

50

60

70

80M

ea

n P

erc

en

t M

eta

ph

ton

co

ve

r

2001

2002

2003

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

7

40

24

14

25

21

27

35

306.5

29

15

32

37

Results

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

R2 = 0.8806

0

10

20

30

40

50

60

70

0.00 5.00 10.00 15.00 20.00

Loading SRP (6/1-8/31, 2003) Kg

Pe

rce

nt

Co

ve

r M

eta

ph

yto

nP=0.06

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

Alternate Method

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Coe

ffici

ent o

f Var

iatio

n

2001

2002

2003

Mean C.V.

2001= 0.883319 +0.385

2002= 0.979605 + 0.110

2003= 0.397958 + 0.137

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