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Phytoplankton, Zooplankton and
Benthos Communities in
Lake Superior
M.L. Tuchman1 & R.P. Barbiero2
1USEPA GLNPO, Chicago, IL USA
2DynCorp I&ET, Chicago, IL USA
Great Lakes National Program Office
• USEPA
• Monitoring Began in 1983
• Current Sampling Includes:
– Phytoplankton
– Zooplankton
– Benthos
– Physical/Chemical Parameters
• Biannual Sampling
– Spring mixed
– Summer stratified
1998 Summer Sampling Stations
Plankton Sites
Plankton & Benthos Sites
Benthos Only Sites
TOPICS
• Focus on:
– Offshore Waters
– Spring; Summer
• Communities Examined:
– Phytoplankton: biovolume; development
– Crustacean: composition, size structure
– Benthos: status of Diporeia
• Current Status - Results from 1999 Survey
Locations of GLNPO Routine Monitoring Sites
Plankton
Plankton & Benthos
Benthos
Major Types of Diatoms
Centrics
Cyclotella
Aulacoseira
Pennates
Fragilaria
Asterionella
Tabellaria
2*106 mm3/ml
1*106 mm3/ml
5*105 mm3/ml
Biovolume (106 mm3/ml)
Phytoplankton Biovolume,
4
Spring 1998
3
2
1
0
SU MI HU ER
ON
Biovolume (106 mm3/ml)
Phytoplankton Biovolume,
4
Spring 1999
2*106 mm3/ml
1*106 mm3/ml
5*105 mm3/ml
3
2
1
0
SU MI HU ER ON
2*106 mm3/ml
1*106 mm3/ml
5*105 mm3/ml
Biovolume (106 mm3/ml)
Phytoplankton Biovolume,
Summer 1998
4
3
2
1
0
SU MI HU ER
ON
Biovolume (106 mm3/ml)
Phytoplankton Biovolume,
Summer 1999 4
2*106 mm3/ml
1*106 mm3/ml
5*105 mm3/ml
3
2
1
0
SU
MI
HU ER ON
Relative Composition of Phytoplankton Communities
1999
Percent Composition
1998
100
100
75
75
50
Spring
50
25
25
0
0
SU
MI
HU
ER
ON
100
100
75
75
Summer
50
SU
MI
HU
ER
ON
SU
MI
HU
ER
ON
50
25
25
0
SU
MI
HU
ER
ON
0
Diatoms
Chrysophytes
Cyanophytes
Chlorophytes
Cryptophytes
Dinoflagellates
OTHER
Phytoplankton - Conclusions
• Biomass Low Relative to Other Lakes
– Lower in spring than summer
• Development Of Phytoplankton Community
Delayed
• Diatoms Persist Further Into Season
• Summer Community Most Similar to Huron
Cladocerans
Daphnia retrocurva
Bosmina longirostris
Photo: SMSU
Photo: Dr. Paul Hebert
Copepods
Mesocyclops
Photo: SMSU
Diaptomus
Photo: USGS
Biomass of Spring Crustaceans 1999
3 g/m2
1 g/m2
Cladocerans
Calanoida
Cyclopoida
Imm Calanoida
Imm Cyclopoida
Biomass of Summer Crustaceans 1999
3 g/m2
1 g/m2
Cladocerans
Calanoida
Cyclopoida
Imm Calanoida
Imm Cyclopoida
Percent Abundance
Biomass of Spring Crustaceans 1999
100
75
50
25
0
SU MI HU W
Cladocerans
Calanoida
Imm Calanoida
Cyclopoida
Imm Cyclopoida
2 g/m2
1 g/m2
< 0.4 g/m2
C E ON
ER
Percent Abundance
Biomass of Summer Crustaceans 1999
100
75
50
25
0
SU MI HU W
Cladocerans
Calanoida
Imm Calanoida
Cyclopoida
Imm Cyclopoida
10 g/m2
5 g/m2
< 1.5 g/m2
C E ON
ER
Biomass (g/m2)
Comparison of Crustacean Biomass
in the Great Lakes, 1999
5
Spring
0
Summer
Biomass (g/m2)
15
10
5
0
SU
MI
HU
ER
ON
30
100
75
50
25
0
20
10
0
0
1
2
< 1 mm
Cumulative
Biomass
Relative
Frequency
Size Frequency Distribution and Cumulative
Biomass of Summer Crustaceans 1999
> 1 mm
Bythotrephes
3
Size (mm)
30
100
75
50
25
0
20
10
0
0
30
100
75
50
25
0
20
10
0
0
1
2
3
1
2
3
30
100
75
50
25
20
10
0
0
0
1
2
3
Size Frequency Distribution and Cumulative
Biomass of Summer Crustaceans 1998, 1999
100
20
75
50
10
25
100
75
50
25
0
0
20
10
100
75
50
25
20
10
0
20
100
0
75
50
25
0
10
0
0
1
2
3
1998
0
0
1
2
1999
3
100
75
20
50
25
100
10
0
20
75
50
25
0
10
0
0
1
2
3
% Biomass
Amount of Biomass Contributed by
Individuals < 1 mm and > 1 mm, Summer, 1998
SU
< 1 mm
> 1 mm
Bythotrephes
10 g/m2
5 g/m2
<1 g/m2
MI
HU
ER ON
% Biomass
Amount of Biomass Contributed by
Individuals < 1 mm and > 1 mm, Summer, 1999
SU
< 1 mm
> 1 mm
Bythotrephes
10 g/m2
5 g/m2
<1 g/m2
MI
HU
ER
ON
Bythotrephes Areal Abundances 1999
1,000/m2
500/m2
100/m2
+
absent
Zooplankton - Conclusions
• Community Makeup:
– Large, deep-living calanoid copepods dominate
– Cyclopoid copepods also abundant
– Percentage of cladocerans lowest of Great Lakes
• Biomass Low Relative to Other Lakes
• Most Biomass in Large Individuals
• ‘Medium’ Sized Individuals Largely Absent
Abundance/m2
Areal Abundances of Benthos
in the Great Lakes, Summer 1999
14000
12000
10000
8000
6000
4000
2000
0
SU
12,000/m2
8,000/m2
4,000/m2
MI
HU
ER
ON
Abundance of Diporeia
Throughout Great Lakes, 1999
6,000 m-2
3,000 m-2
1,000 m-2
+
0 m-2
Changes in Diporeia Abundance, 1997-1999
-
-
+/-
#/m2
2000
1000
0
+
Diporeia Abundance in Relation to
SOLEC Criteria, 1999
Better Than SOLEC Criteria
Meets SOLEC Criteria
Worse Than SOLEC Criteria
SOLEC Criteria:
Depth < 100m: 220-320/m2
Depth > 100m: 30-160/m2