Little Rock Lake Experiment at North Temperate Lakes LTER: Zooplankton length 1988 - 1998

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. Zooplankton samples are collected from the treatment and reference basins of Little Rock Lake at at two to nine depths using a 30L Schindler Patalas trap (53um mesh). Zooplankton samples are preserved in buffered formalin and archived. Data are summed over sex and stage and integrated volumetrically over the water column to provide a lake-wide estimate of average length of organisms for each species.

小石城酸化实验（The Little Rock Acidification Experiment）是一项由美国环境保护署（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联合开展的合作研究项目。小石罗湖（Little Rock Lake）是坐落于美国威斯康星州维拉斯县的双叶型湖泊。1983年，该湖通过不透水幕布被分隔为两个独立盆地；1984年至1989年间，研究团队分三个为期两年的阶段，采用硫酸对湖北部处理盆地开展酸化操控，三个阶段的目标pH值依次为1984-1985年的5.7、1986-1987年的5.2，以及1988-1989年的4.7。自1990年起，在保留分隔幕布的前提下，该湖进入自然恢复阶段，相关数据采集工作持续至2000年。本项目的核心研究目标为阐明完整湖泊生态系统的种群、群落及生态系统对全湖酸化的响应规律。本项目由美国环境保护署（USEPA）与美国国家科学基金会（NSF）提供资助。采样环节中，研究人员使用30L辛德拉-帕塔拉斯采样器（Schindler Patalas trap，53μm网目），在小石罗湖的处理盆地与对照盆地中，于2至9个不同水深采集浮游动物（Zooplankton）样本。浮游动物样本经缓冲福尔马林溶液固定后进行归档保存。后续分析时，研究人员按性别与发育阶段汇总样本数据，并对全水柱进行体积积分处理，以此得到各物种在全湖范围内的平均体长估算值。