Long-Term Ecological Research (LTER)/NTL002: Chemical Limnology of North Temperate Lakes Primary Study Lakes

LTER - Long-Term Ecological Research Program/North Temperate Lakes (NTL)

LTER/NTL002 [Summary adapted from the LTER Core Data Set Catalog]:

Parameters characterizing the chemical limnology of the seven primary lakes (Allequash, Big Muskellunge, Crystal, Sparkling, and Trout lakes and unnamed lakes 27-02, and 12-15) are measured at one station in the deepest part of each lake at the top and bottom of the epilimnion, midthermocline, and top, middle, and bottom of the hypolimnion. These parameters include total nitrogen, total dissolved nitrogen, nitrate, ammonia, total phosphorus, total dissolved phosphorus, total silica, dissolved reactive silica, field pH, air equilibrated pH, total alkalinity, total inorganic carbon, dissolved inorganic carbon, total organic carbon, dissolved organic carbon, total particulate matter, chloride, sulphate, calcium, magnesium, sodium, potassium, iron, manganese, and specific conductance.

Special Comments: These measurements are made concurrently with parameters listed in physical (NTL001) and plankton (NTL003) databases. Derived data sets containing epilimnetic averages and hypsometrically weighted averages over depths are also available.

The North Temperate Lakes (NTL) site is affiliated with the Center for Limnology at the University of Wisconsin, Madison. The NTL site focuses its research on north temperate lake ecosystems in the Northern Highland Lakes District of Wisconsin. The Northern Highland Lakes District, has an area of approximately 10,000 sq. km. and has one of the highest concentrations of lakes in the world. Lakes range in size from 0.1 to 1,500 ha, in depth from 1 to 33 m, and in fertility from oligotrophic to eutrophic. Other representative limnological conditions include: rainwater dominated, groundwater dominated and drainage lakes; dystrophic lakes; lakes with varved sediments, winterkill lakes, temporary and permanent forest ponds, and reservoirs. Lakes are influenced by strong seasonality and are usually ice covered from late November to late April. Lakes within the Northern Highland exhibit near-natural water quality conditions. Nearly 80% of the land area and two-thirds of the lake frontage are protected.