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A lake-wide approach for large lake zooplankton monitoring: Results from the 2006–2016 Lake Superior Cooperative Science and MonitoringInitiative surveys
Citation:
Pawlowski, M. AND M. Sierszen. A lake-wide approach for large lake zooplankton monitoring: Results from the 2006–2016 Lake Superior Cooperative Science and MonitoringInitiative surveys. JOURNAL OF GREAT LAKES RESEARCH. International Association for Great Lakes Research, Ann Arbor, MI, 46(4):1015-1027, (2020). https://doi.org/10.1016/j.jglr.2020.05.005
Impact/Purpose:
This manuscript summarizes trends in total crustacean and rotifer abundance in Lake Superior from three intensive surveys of the lake spanning 2006-2016. This work demonstrates that zooplankton abundance is stable in Lake Superior, compared to the other Great Lakes and will facilitate future monitoring efforts. This paper also analyzes spatial differences in zooplankton across Lake Superior and demonstrates the use of trends analyses that future work will find useful.
Description:
Under the Great Lakes Cooperative Science and Monitoring Initiative (CSMI), intensive, whole-lake surveys of Lake Superior were completed during late summer in 2006, 2011, and 2016 to assess lower food web condition. These surveys used a depth-stratified probability approach to select spatially balanced sampling locations and to allow for characterization and assessment of food web conditions within depth strata. We evaluated differences among depth strata and among surveys in zooplankton abundance, community composition, and relative abundance in the epilimnion in nearshore (100m) areas. While crustacean biomass differed slightly from survey to survey, total crustacean biomass did not differ across the three surveys in any depth strata nor did the relative amount of total crustacean biomass in the epilimnion. Total rotifer densities declined over the three surveys in the nearshore, apparently the result of smaller densities of Kellicottia and Keratella. Changes in the community compositions of crustaceans and rotifers were minimal, with only a small decline in the relative biomass of cyclopoids in the nearshore and offshore. Data from annual EPA surveys also suggested that offshore cyclopoid biomass declined in the past two decades, but that overall crustacean biomass and community structure have been stable. The CSMI surveys provide spatially comprehensive zooplankton data, including data for nearshore waters which are not routinely sampled in other monitoring programs. Changes in zooplankton communities that do occur may not occur uniformly across depth strata, and this work demonstrate the usefulness of depth-stratified probability surveys for zooplankton monitoring.
URLs/Downloads:
DOI: A lake-wide approach for large lake zooplankton monitoring: Results from the 2006–2016 Lake Superior Cooperative Science and MonitoringInitiative surveys