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（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湖与Fish湖）的营养盐化学特征参数开展测定。于每个湖泊最深单点站位处，分别采集表水层（epilimnion）上层与下层、温跃层中部，以及深水层（hypolimnion）上层、中层与下层的水样。本次测定的参数包括总氮、总溶解态氮（仅北部湖泊测定）、硝酸盐、氨氮、总磷、总溶解态磷（仅北部湖泊测定）、溶解反应性磷（仅南部湖泊测定，且2003年后的Wingra湖与Fish湖未测定该参数）、碳酸氢盐反应性过滤与未过滤二氧化硅（两项均于2003年停止测定）、溶解反应性二氧化硅、现场pH值、空气平衡pH值、总碱度、总无机碳、溶解无机碳、总有机碳、溶解有机碳，以及总颗粒物（本数据集中仅北部湖泊测定该参数；2000年起南部湖泊的总颗粒物数据收录于另一独立数据集）。采样频率规则如下：北部湖泊在无冰期每月采样一次，冰封期每6周采样一次；南部湖泊采样规则类似，但秋季为每月采样，冬季通常仅采样一次（视冰情而定）。本次研究共设置11个采样站点。