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个主要湖泊（阿勒夸什湖（Allequash）、大麝香鲈湖（Big Muskellunge）、水晶湖（Crystal）、斯帕克林湖（Sparkling）、特劳特湖（Trout），编号27-02[水晶沼（Crystal Bog）]与12-15[特劳特沼（Trout Bog）]的未命名湖泊，以及门多塔湖（Mendota）、莫诺纳湖（Monona）、温格拉湖（Wingra）与菲什湖（Fish））的营养盐化学特征参数，于各湖泊最深点位的表水层（epilimnion）顶部与底部、温跃层中部，以及湖下层（hypolimnion）的顶部、中部与底部开展测定。所测定的参数包括总氮、总溶解态氮（仅在北部湖泊中测定）、硝酸盐、氨氮、总磷、总溶解态磷（仅在北部湖泊中测定）、溶解性反应磷（仅在南部湖泊中测定，且2003年起温格拉湖与菲什湖不再测定该参数）、碳酸氢盐反应型过滤与未过滤二氧化硅（两项测定均于2003年停止）、溶解性反应型二氧化硅、现场pH值、空气平衡pH值、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（本数据集仅覆盖北部湖泊的总颗粒物测定数据；2000年起南部湖泊的总颗粒物数据可从另一独立数据集获取）。采样频率：北部湖泊在无冰期每月采样1次，冰盖期每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（视冰情条件而定）。采样点位总数：11个