USING SEDIMENT CORES FOR
MANAGING LAKES
Paul Garrison
Bureau of Science
Services
HOW DO YOU COLLECT SEDIMENT CORES?
Gravity Corer
Piston Corer
CORED LAKES
140 Lakes
Types of Cores
Full core
Top/Bottom
Modern
Sedimentation Rate
2000
1980
1960
1940
1920
1900
1880
1860
1840
1820
0
0.1
0.2
-2
(g cm yr-1)
0.3
Reference
WHAT INFORMATION IS RECORDED IN THE
SEDIMENTS?
•Geochemistry
•Nutrients -- phosphorus, nitrogen
•Soil erosion--aluminum, titantium
•Urbanization--zinc, copper
•Synthetic fertilizer--uranium, cadmium
•Anoxia--iron, manganese
•Diatoms
•Water quality history
•nutrients
•pH
•General aquatic plant growth
•Blue-green algae
•Plant remains
•History of macrophytes
Lead-210 Dating
222 Radon
210 Lead
222 Radon
226
Radium
238 Uranium
HALF LIVES
226 Radium 1024 yr
222 Radon 3.8 days
210 Lead
22.26 yr
FALLOUT FROM ATMOSPHERIC
BOMB TESTING
C
e
s
iu
m
D
a
tin
g
0
1
0
Depth(cm)
1
9
6
3
2
0
1
9
5
4
3
0
4
0
0
.0
0
0
.2
0
0
.4
0
0
.6
0
C
s
-1
3
7
:K
-4
0
0
.8
0
MACROPHYTE
CONTROL
GASOLINE
EMISSIONS
Arsenic
Western Basin
2000
1990
1980
1970
1960
1950
1940
1930
1920
1910
1900
1890
1880
1870
1860
0
2
4
Depth (cm)
6
8
10
12
1962
14
16
18
20
1975
0
0.0
0.5
1.0
Concentration (mg/g)
1.5
2.0
20
40
Lead Conc (mg/kg)
60
DIATOMS
BLUE-GREEN and GREEN ALGAE
AGRICULTURE
Circa 1880
Circa 1910
Green
Lake
Green Lake
Titanium
Uranium
Soil Erosion
Manganese
Fertilizer
Low Oxygen
2000
1990
1970
1950
1930
1980
1960
1940
1920
1900
1880
1860
1840
0.00
0.05
0.10
0.15
0.00
0.01
Western Basin
2000
0.02
0.03
0.04
10
15
20
25
Eastern Basin
1990
1970
1950
1930
1980
1960
1940
1920
1900
1880
1860
1840
Increasing Phosphorus Concentrations
SHORELAND DEVELOPMENT
circa 1940
2009
HABITAT CHANGE
circa 1910
Little
Bearskin
Lake
Little Bearskin Lake
FERNLEAF PONDWEED
Present Day
circa 1930s
1800s
0
500
1000
1500
2000
2500
COONTAIL
Present Day
circa 1930s
1800s
0
500
1000
1500
2000
LARGE LEAVED PONDWEED
Present Day
circa 1930s
1800s
0
50
100
Number
150
g-1
200
250
Little Bearskin Lake
DIATOMS
Present Day 2
Historical 1
0
20
40
60
Percentage
Open-water
Macrophyte
80
100
Shift in the ratio of isoetids to elodeids
1930s: 50/50
2000s: 30/70
Susan Borman and Ray Newman-U. of Minnesota
CHANGE IN PHOSPHORUS
SUMMER PHOSPHORUS
40
Modern
Reference
30
n = 73
µg L-1
20
10
0
Northern Lakes
CHANGING WATER LEVELS
Berry Lake, Oconto County
LAKE TYPE: Seepage
Berry
Lake
AREA: 81 ha
MAXIMUM DEPTH: 8.2 meters
MEAN DEPTH: 2.1 meters
SHORELINE PROPERTIES: 113
or 21 dwellings per kilometer
LAKE LEVEL
Lake Elevation (ft)
98
96
nearly 8 foot change
94
92
90
88
1930
1940
1950
1960
1970
1980
1990
2000
2010
Dr. Samatha Kaplan—
UW Stevens Point
Floral foam
50
0 cm
100
11,521 BP
60
10
110
70
20
296 BP
120
80
934 BP
30
130
391 BP
40
50 cm
12,752 BP
90
2730 BP
97 cm
133 cm
Floral foam
Phosphorus
2000
HIGH
1980
LOW
1960
`
1940
1920
1900
5
10
15
µg
L-1
20
25
Lake
Chetac
BLUE-GREEN ALGAE
Anabaena
Aphanizomenon
Gloetrichia
2000
1980
1960
1940
1920
1900
1880
1860
1840
0
4
8
12 0
5
10
15
20 0
106 Fossils g-1 dry sed-1
5
10
LAKE CHETAC
Secchi
Phosphorus
2000
2000
1980
1980
1960
1960
1940
1940
1920
1920
1900
1900
1880
1880
1860
1860
1840
1840
1
2
3
Feet
4
0
50
100
µg L-1
150
PHOSPHORUS STANDARDS
SUMMER PHOSPHORUS
40
n = 17
n = 19
30
µg L-1
n = 43
n = 11
n = 15
n = 29
20
10
0
1
2
3
4
5
6
Shallow
Deep
Shallow
Deep
Shallow
Deep
Drainage
Seepage
CLASS
REFERENCE
75TH
PERCENTILE
1
24
30
2
18
20
3
25
30
4
19
20
5
16
17
6
13
15
SUMMARY
•Many lakes with significant agriculture in their watersheds
have experienced a reduction in soil erosion during the last
30 years but not necessarily a reduction in nutrient input
because of the use of synthetic fertilizers.
•In northern lakes that have experienced increased
shoreland development during the last 2-3 decades,
phosphorus levels may not have increased, but nearly all of
these lakes have experienced an increase in plant growth.
•With a change in our climate - watershed landuse will have
the greatest impact on nutrients.
PALEOLIMNOLOGY AS A LAKE
MANAGEMENT TOOL
•How is the current lake condition different from
historical?
•If there has been a change, how much has it been
and what are the major causes?
•How much of an effort do we want to put into
improving our lake given fiscal and political costs?
37
LAKETIDES
Winter 2007
Winter 2008
QUESTIONS?