Little Rock Lake Experiment at North Temperate Lakes LTER: Nutrients 1996 - 2000

The Little Rock Acidification Experiment was a joint project involving the USEPA (Duluth Lab), University of Minnesota-Twin Cities, University of Wisconsin-Superior, University of Wisconsin-Madison, and the Wisconsin Department of Natural Resources. Little Rock Lake is a bi-lobed lake in Vilas County, Wisconsin, USA. In 1983 the lake was divided in half by an impermeable curtain and from 1984-1989 the northern basin of the lake was acidified with sulfuric acid in three two-year stages. The target pHs for 1984-5, 1986-7, and 1988-9 were 5.7, 5.2, and 4.7, respectively. Starting in 1990 the lake was allowed to recover naturally with the curtain still in place. Data were collected through 2000. The main objective was to understand the population, community, and ecosystem responses to whole-lake acidification. Funding for this project was provided by the USEPA and NSF. Parameters characterizing the nutrient chemistry of the treatment and reference basins of Little Rock Lake are measured at one station in the deepest part of each basin 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, nitrate, ammonia, total phosphorus, total dissolved phosphorus, dissolved reactive phosphorus, bicarbonite-reactive filtered and unfiltered silica, dissolved reactive silica, total inorganic carbon, dissolved inorganic carbon, total organic carbon, dissolved organic carbon, and total particulate matter. Sampling Frequency: varies - Number of sites: 2小石湖酸化实验（Little Rock Acidification Experiment）是一项联合研究项目，参与方包括美国环境保护署（USEPA，德卢斯实验室）、明尼苏达大学双城分校、威斯康星大学苏必利尔分校、威斯康星大学麦迪逊分校以及威斯康星州自然资源部。小石湖（Little Rock Lake）坐落于美国威斯康星州维拉斯县，为双瓣形湖泊。1983年，该湖通过一道不透水防渗帷幕被分割为两部分；1984年至1989年，研究团队分三个为期两年的阶段，通过施加硫酸对湖北部盆地进行酸化处理，三个阶段的目标pH值分别为1984-1985年的5.7、1986-1987年的5.2以及1988-1989年的4.7。1990年起，在防渗帷幕保留的前提下，湖泊进入自然恢复阶段，相关数据采集工作持续至2000年。 本实验的核心目标是阐明种群、群落及生态系统对全湖酸化的响应过程。本项目由美国环境保护署（USEPA）与美国国家科学基金会（NSF）资助。 研究人员针对小石湖处理组与参照组两个盆地的营养盐化学特征开展测定：在每个盆地的最深点位分别采集湖上层（epilimnion）的表层、底层水样，温跃层中层水样，以及湖下层（hypolimnion）的表层、中层与底层水样。测定参数包括总氮、总溶解氮、硝酸盐、氨氮、总磷、总溶解磷、溶解性反应磷、碳酸氢盐反应型过滤与未过滤二氧化硅、溶解性反应性二氧化硅、总无机碳、溶解性无机碳、总有机碳、溶解性有机碳以及总颗粒物。 采样频次：不固定；采样点位数量：2个。