North Temperate Lakes LTER: Chemical Limnology of Primary Study Lakes: Major Ions 1981 - current

Parameters characterizing the major ions of the eleven primary lakes (Allequash, Big Muskellunge, Crystal, Sparkling, Trout, bog lakes 27-02 [Crystal Bog], and 12-15 [Trout Bog], Mendota, Monona, Wingra and Fish) are measured at one station in the deepest part of each lake at the top and bottom of the epilimnion, mid-thermocline, and top, middle, and bottom of the hypolimnion. These parameters include chloride, sulfate, calcium, magnesium, sodium, potassium, iron, manganese, and specific conductance (northern lakes only). Lake Wingra has always been just a surface sample, but in the winter we have, at times, taken chloride samples from top to bottom to have a better understanding of road salt effects. Samples for conductivity are collected four times per year in the seven primary lakes (Allequash, Big Muskellunge, Crystal, Sparkling, and Trout lakes, and unnamed lakes 27-02 [Crystal Bog], and 12-15 [Trout Bog] in the Trout Lake area at the deepest part of the lake, sampling at the surface, mid water column, and the bottom. The sampling dates include February under ice, spring mixis, August stratified, and fall mixis. Conductivity is measured using a YSI Model 32 conductivity meter with YSI 3403 conductivity cell, reported as uS/cm at 25°C. 1981-1988: a Sybron Barnstead conductivity bridge was used. 1981-1986: conductivity was measured monthly. Sampling Frequency: quarterly (winter, spring and fall mixes, and summer stratified periods) Number of sites: 11