Little Rock Lake Experiment at North Temperate Lakes LTER: pH and Alkalinity 1983 - 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. pH and alkalinity 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. During the course of the study, three different
types of electrodes were used to measure pH. 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。小石湖是美国威斯康星州维拉斯县的双叶状湖泊（bi-lobed lake）。1983年，该湖通过不透水帷幕（impermeable curtain）被分割为两个湖盆；1984年至1989年间，研究团队分三个为期两年的阶段向湖北部湖盆施加硫酸以实施酸化处理，三个阶段的目标pH值分别为5.7（1984-1985年）、5.2（1986-1987年）与4.7（1988-1989年）。自1990年起，在保留不透水帷幕的前提下，湖泊进入自然恢复阶段。研究数据采集工作持续至2000年。本项目的核心研究目标为解析完整湖泊生态系统在种群、群落及生态系统尺度上对酸化作用的响应机制。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。研究人员在处理组与参照组湖盆的最深点位各设置一个监测站，分别于表水层（epilimnion）上下部、温跃层中部以及下层滞水带（hypolimnion）的上、中、下部测定pH值与碱度。研究期间共使用三种不同类型的pH电极开展测量。采样频率：不固定；采样点位数量：2个。