Weir (Marion County)

Florida LAKEWATCH Water Chemistry Summary

Location: Latitude 29°1'5", Longitude 81°56'12"

Period of record: 100 sampling dates; March 9, 1990 to December 10, 1999

Surface area (LAKEWATCH): No data available.     Bathymetric Map

Lake Region (Griffith et al. 1997): Lake Weir/Leesburg Upland

Geologic formation (Brooks 1981):

The geology is dominated by deeply weathered clayey sand and granular sand of the Hawthorne Formation.

Physiographic region (Brooks 1981):

The water body lies in the Central Lakes division of the Central Lake District.

Supplemental, unpublished water chemistry data, University of Florida.

Numbers reported below are the average for 4 months sampled:
 
pH
7.1
Sulfate (mg/L)
8.4
Total alkalinity (mg/L as CaCO3)
23.5
Calcium (mg/L)
4.0
Conductance (µS/cm @ 25 °C)
151
Magnesium (mg/L)
14.8
Color (Pt-Co units)
4
Sodium (mg/L)
16.8
Chloride (mg/L)
23.8
Potassium (mg/L)
2.0
Silicon (mg/L)
0.1
   

Long-term Florida LAKEWATCH Data

Numbers reported below are the minimum, average, and maximum value for the 100 months sampled:

 
Minimum
Average
Maximum
Long-term total phosphorus concentrations (µg/L)
6
11
26
Long-term total nitrogen concentrations (µg/L)
290
740
970
Long-term total chlorophyll concentrations (µg/L)
3.0
11.2
21.3
Long-term Secchi depth (ft)
4.3
6.5
12.2

1999 Florida LAKEWATCH Data

Numbers reported below are monthly averages calculated from 3 stations for total phosphorus (TP, µg/L), total nitrogen (TN, µg/L), chlorophyll (CHL, µg/L) and Secchi depth (SECCHI, ft) during 1999:

Date
TP (µg/L)
TN (µg/L)
CHL (µg/L)
SECCHI (ft
Jan-15-99
15
610
12.3
5.9
Feb-26-99
11
680
11.3
6.3
Mar-19-99
13
640
9.0
6.2
Apr-23-99
10
670
9.0
6.9
May-28-99
11
640
10.7
6.1
Jun-15-99
10
700
10.0
6.3
Jul-09-99
10
640
9.7
6.9
Aug-17-99
9
750
9.0
7.4
Sep-24-99
10
830
11.0
6.2
Oct-24-99
9
840
13.0
6.6
Nov-28-99
13
890
12.0
5.7
Dec-10-99
9
770
11.7
5.9
         
1999 Average
11
720
10.7
6.3

 

Weir (Marion County)

Florida LAKEWATCH Aquatic Plant Summary

Aquatic plant data collected on June 25, 1992

Percent area covered with aquatic vegetation (PAC, %)
14
Percent of lake's volume filled with vegetation (PVI, %)
2
Average emergent plant biomass (kg wet wt/m2)
1.9
Average floating-leaved plant biomass (kg wet wt/m2)
0.0
Average submersed plant biomass (kg wet wt/m2)
0.4
Average width of emergent and floating-leaved zone (ft.)
106
Average lake depth (m)
5

 

Frequency that plant species occur in 20 evenly spaced transects around the lake.

Common Name Plant Species
Frequency (%)
maidencane Panicum hemitomon
80
rush fuirena Fuirena scirpoidea
80
Illinois pondweed Potamogeton illinoensis
55
torpedograss Panicum repens
55
water primrose Ludwigia octovalvis
50
lemon bacopa Bacopa caroliniana
35
knot grass Paspalum distichum
35
duck-potato Sagittaria lancifolia
15
water-pennywort Hydrocotyle umbellata
15
red root Lachnanthes caroliniana
15
slender spikerush Eleocharis baldwinii
10
smartweed Polygonum hydropiperoides
10
willow Salix spp.
10
respuinata bladderwort Utricularia resupinata
10
cat-tail Typha spp.
5
tapegrass Vallisneria americana
5
buttonbush Cephalanthus occidentalis
5
sawgrass Cladium jamaicense
5
flat-sedge Cyperus odoratus
5
southern water-grass Hydrochloa caroliniensis
5
rush spp. Juncus dichotomus
5
jointed flat sedge Cyperus haspan
5

 

Weir (Marion County)

Florida LAKEWATCH Aquatic Plant Summary

Aquatic plant data collected on July 15, 1998

Percent area covered with aquatic vegetation (PAC, %)
6
Percent of lake's volume filled with vegetation (PVI, %)
0
Average emergent plant biomass (kg wet wt/m2)
1.4
Average floating-leaved plant biomass (kg wet wt/m2)
0.0
Average submersed plant biomass (kg wet wt/m2)
0.2
Average width of emergent and floating-leaved zone (ft.)
70
Average lake depth (m)
6

 

Frequency that plant species occur in 20 evenly spaced transects around the lake.

Common Name Plant Species
Frequency (%)
maidencane Panicum hemitomon
95
rush fuirena Fuirena scirpoidea
90
duck-potato Sagittaria lancifolia
80
respuinata bladderwort Utricularia resupinata
75
wax myrtle Myrica cerifera
55
water primrose Ludwigia octovalvis
55
torpedograss Panicum repens
55
willow Salix spp.
45
stonewort Nitella spp.
45
red root Lachnanthes caroliniana
45
red maple Acer rubrum
40
buttonbush Cephalanthus occidentalis
30
musk-grass Chara spp.
25
knot grass Paspalum distichum
25
cat-tail Typha spp.
20
Illinois pondweed Potamogeton illinoensis
20
salt-bush Baccharis spp.
20
sweetbay Magnolia virginiana
20
lemon bacopa Bacopa caroliniana
15
water-pennywort Hydrocotyle umbellata
10
sawgrass Cladium jamaicense
10
giant reed Phragmites australis
10
rush spp. Juncus dichotomus
10
slender spikerush Eleocharis baldwinii
5
red ludwigia Ludwigia repens
5
elephant-ear Colocasia esculenta
5
leconte sedge Cyperus lecontei
5
elderberry Sambucus canadensis
5
sweetgum Liquidambar styraciflua
5

 

Weir (Marion County)

Electrofishing Data

     
Canfield and Hoyer (1992) Ranges
Species1
#/hr
kg/hr2
min weight (kg/hr)
mean weight (kg/hr)
max weight (kg/hr)
Black crappie
3
1.2
0.1
6.4
28.7
Bluegill
84
5
0.3
50.3
447
Bowfin
1
1
3
54.5
225
Brook silverside
1
0
0
0.2
1.4
Chain pickerel
8
7.5
0
17.5
57.1
Florida gar
11
7.8
0.8
50.1
328.6
Golden shiner
3
0.1
0
6.9
65
Lake chubsucker
8
5.5
0.1
40.7
161.9
Largemouth bass
53
14.3
1.1
82
284.6
 
19
2.7
0.1
24.3
183.1
Seminole killifish
2
0
0
4.2
22.3
           
Total
193
45.1
     

 

1 Total # of species = 11.
2 Weights calculated using regressions from Hoyer and Canfield 1994 and from Bill Schaeffer, Florida Fish and Wildlife Conservation Commission (personal communication).




 
 

Catch per unit of effort (kg of fish / hour of sampling) versus total chlorophyll (mg/m3) and number of fish species collected versus surface area of lake for 60 Florida lakes sampled by Canfield and Hoyer (1992) () and Lake Weir (Marion County) electrofishing sampling (o). The lines represent linear regressions for logged values of the 60 Florida lakes.

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