North Temperate Lakes LTER: Chemical Limnology of Primary Study Lakes: Nutrients, pH and Carbon 1981 - current

Parameters characterizing the nutrient chemistry of the eleven primary lakes (Allequash, Big Muskellunge, Crystal, Sparkling, and Trout lakes, unnamed 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 total nitrogen, total dissolved nitrogen (only in the northern lakes), nitrate, ammonia, total phosphorus, total dissolved phosphorus (only in the northern lakes), dissolved reactive phosphorus (only in the southern lakes and not in Wingra and Fish after 2003), bicarbonite-reactive filtered and unfiltered silica (both discontinued in 2003), dissolved reactive silica, field pH, air equilibrated pH, total alkalinity, total inorganic carbon, dissolved inorganic carbon, total organic carbon, dissolved organic carbon, and total particulate matter (only in the northern lakes in this data set. Total particulate matter in southern lakes starting in 2000 is available in a separate dataset). Sampling Frequency: monthly during ice-free season - every 6 weeks during ice-covered season for the northern lakes. The southern lakes are similar except that sampling occurs monthly during the fall and typically only once during the winter (depending on ice conditions). Number of sites: 11

本数据集针对11处主要湖泊的营养盐化学特征参数开展测定，涉及湖泊包括Allequash湖、Big Muskellunge湖、Crystal湖、Sparkling湖、Trout湖，未命名湖泊27-02［Crystal Bog］与12-15［Trout Bog］，以及Mendota湖、Monona湖、Wingra湖和Fish湖。采样站位设于各湖最深点位，分别采集表水层（epilimnion）顶部与底部、温跃层中部（mid-thermocline），以及下层滞水层（hypolimnion）顶部、中部和底部的水样。测定参数涵盖总氮、总溶解氮（仅在北部湖泊测定）、硝酸盐、氨氮、总磷、总溶解磷（仅在北部湖泊测定）、溶解性活性磷（仅在南部湖泊测定，且2003年起Wingra湖与Fish湖不再测定该指标）、重碳酸盐型可滤与不可滤活性硅（两项指标均于2003年停止测定）、溶解性活性硅、现场pH、空气平衡pH、总碱度、总无机碳、溶解态无机碳、总有机碳、溶解态有机碳，以及总颗粒物（本数据集中仅涵盖北部湖泊的总颗粒物数据；2000年起南部湖泊的总颗粒物数据可通过另一独立数据集获取）。采样频率规则如下：北部湖泊在无冰期每月采样1次，冰期每6周采样1次；南部湖泊采样规则基本一致，但秋季维持每月采样，冬季通常仅采样1次，具体视冰情而定。本数据集共设11个采样站位。