NTL Lakes | North Temperate Lakes

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The focus is on a suite of lakes linked through a common groundwater and surface flow system as well as common climatic, edaphic, and biogeographic systems facilitating landscape as well as long-term ecological research. The suite includes oligotrophic, dystrophic, and mesotrophic lakes and a gradient in the portion that precipitation, groundwater, and surface water contribute to the input of their hydrologic budgets. The seven northern lakes, located in north central Wisconsin, were chosen to represent marked differences in size, morphometry and habitat diversity, in thermal and climatic features, in species richness and assemblies, and in biological productivity. Sparkling Lake and Crystal Lake have been experimentally manipulated by NTL and the Wisconsin Department of Natural Resources regularly stocks many lakes, sets bag limits and regulates shoreline maintenance. These lakes are located within the Northern Highland-American Legion State Forest, Vilas County.

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In 1994 four primary study lakes in southern Wisconsin were added. These four eutrophic lakes were chosen in a 2x2 design of urban vs. agricultural setting and headwater vs. lower in the landscape. Lake Mendota and Lake Wingra have been experimentally manipulated by NTL. All lakes are managed for recreational use with regular fish stocking, bag limits, shore regulations, and macrophyte mowing activities.

Trout Lake Region Lake Characteristics


Characteristic	Crystal Bog (27-2)	Trout Bog (12-15)	Crystal Lake	Big Muskellunge Lake	Sparkling Lake	Allequash Lake	Trout Lake
Latitude	46.008	46.041	46.003	46.021	46.008	46.038	46.029
Longitude	-89.606	-89.686	-89.612	-89.612	-89.701	-89.621	-89.665
Area (ha)	0.6	1.0	37.5	363.4	63.7	164.2	1565.1
Mean Depth (m)	1.7	5.6	10.4	7.5	10.9	2.9	14.6
Maximum Depth (m)	2.5	7.9	20.4	21.3	20	8	35.7
Lake Benchmark (m)
Shoreline Length (km)	0.285	0.369	2.3	16.1	4.3	9.5	25.9
Landscape Position	High	high	high	intermediate	intermediate	low	low
Development on shoreline	low	low	low (campground)	moderate	moderate	low	moderate
Duration of ice cover (days)	152	154	138	141	136	147	135
Water Temperature (°C)	19.9	17.9	21.0	21.2	21.1	21.6	20.1
pH	5.2	4.8	6.1	7.3	7.4	7.6	7.6
ANC (µeq/L)	14	11	23	390	631	831	846
Conductivity (µS/cm)	11	23	13	50	86	92	96
Total P (µg/l)	18.2	46.6	8.3	17.5	15.0	29.3	13.5
Total N (µg/l)	722	961	210	441	371	379	247
SiO2 (µg/l)	834	1927	48	309	7217	13853	9529
Secchi Depth (m)	1.5	1.1	7.5	6.6	6.2	3.2	4.7
Chlorophyll (µg/l)	9.9	16.2	1.8	2.9	2.2	7.8	3.1
Number of fish species	1	3	24	34	30	36	42
Experimental Manipulations			Thermal manipulation, Smelt removal, Cisco introduction		Crayfish removal, Smelt removal, Cisco introduction

Madison Lakes Region Lake Characteristics


Characteristic	Fish Lake	Lake Mendota	Lake Wingra	Lake Monona
Latitude	43.287	43.099	43.053	43.063
Longitude	-89.652	-89.405	-89.425	-89.361
Area (ha)	80.4	3961.2	136.2	1359.8
Mean Depth (m)	6.6	12.8	2.7	8.2
Maximum Depth (m)	18.9	25.3	6.7	22.5
Shoreline Length (km)	4.3	33.8	5.9	20.9
Landscape position	high	low	high	low
Development on shoreline	high	high	high	high
Duration of ice cover (days)		119	120	107
Water Temperature (°C)	23.9	22.4	23.9	23.3
pH	8.1	8.4	8.5	8.5
ANC (µeq/L)	2921	3665	3745	3547
Conductivity (µS/cm)	280	412	500	434
Total P (µg/l)	22.4	109.5	40.3	73.5
Total N (µg/l)	835	860	933	845
SiO2 (µg/l)	367	711	5551	454
Secchi Depth (m)	2.4	3.0	0.7	2.4
Chlorophyll (µg/l)	5.1	4.8	10.5	8.1
Number of fish species	26	43	29	41
Experimental Manipulations		Food web manipulation	Carp removal

Note:
water temperature (0 - 2m) and secchi from June 1 - August 31
pH, ANC and conductivity from the average of spring and fall mixis sampling
total P, total N and SiO2 from spring mixis sampling
chlorophyll (surface) from open water season