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 chlimatic features, in species richness and assemblies, and in biological productivity. These lakes are located within the Northern Highland-American Legion State Forest, Vilas County.
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) | 0.5 | 1.1 | 36.7 | 396.3 | 64 | 168.4 | 1607.9 |
| 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) |
|
|
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 |
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.
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) | 87.4 | 3937.7 | 139.6 | 1324 |
| 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 |
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