Rationale for data collection and interpretation in the Northern Lakes Long-Term Ecological Program
The Northern Lakes Long-Term Ecological Research Program has three general goals: (1) to detect long-term changes in physical, chemical, and biotic features of lakes, (2) to understand linkages among water and sediment chemistry, hydrology, climate, and biology, and (3) to detect lake features associated with stability and resilience to natural and human disturbance. To accomplish these goals we selected eight northern Wisconsin lakes for semi-intensive study. These lakes lie in the same local groundwater flow system and include oligotrophic, mesotrophic, and dystrophic types. To meet the first goal we have established an ongoing sampling program to provide seasonal or annual estimates of important physical (including light penetration and heat budgets), chemical (including nutrients, pH, alkalinity, and major cations and anions), and biotic (including phytoplankton, zooplankton, macroinvertebrates, and fish) parameters. Frequency and timing of measurements are designed to allow comparisons among lakes, seasons, or years. In addition, we are making long-term comparisons of recent data with those collected from the same lakes by Birge and Juday in the 1930’s. To accomplish the second goal we have instituted a series of shorter term, process-oriented studies designed to describe mechanisms of interaction among system parts and to help us refine our sampling protocol. To meet the third goal we are involved in a whole-lake acidification experiment and in ecological studies of invading fish and crayfish.
American Society for Testing and Materials