Little Rock Lake Experiment at North Temperate Lakes LTER: Zooplankton 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. 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 organisms per liter
for each species. Sampling Frequency: varies - Number of sites: 2