TY - JOUR AU - AB - A stratified-random selection of all lakes in the northeastern United States was sampled for zooplankton composition, and physical and chemical characteristics during midsummer 1986. In all, 146 lakes were sampled from five geographic subregions and three categories of water alkalinity. There was no significant variation in total zooplankton abundance among regions or alkalinity categories; however, the body-size structure of assemblages was dependent on both alkalinity and geographic subregion. The largest change in size structure occurred at alkalinity levels > 150 μeq∙L−1 and pH > 7.0, and appeared less related to change in pH than to variation in water hardness. This shift of size structure was caused by a loss of large-bodied zooplankton and an increase in small rotifers with decreasing water hardness. Exploratory analysis revealed that lake stratification also explained significant variation in zooplankton size structure, but was largely independent of the effects of water chemistry. We hypothesize that the association of large zooplankton with hard water is casual; large-bodied cladocerans may require high calcium levels. TI - Influence of Water Chemistry on Size Structure of Zooplankton Assemblages JF - Canadian Journal of Fisheries and Aquatic Sciences DO - 10.1139/f90-218 DA - 1990-10-01 UR - https://www.deepdyve.com/lp/crossref/influence-of-water-chemistry-on-size-structure-of-zooplankton-KP02bsaLnn SP - 1937 EP - 1943 VL - 47 IS - 10 DP - DeepDyve ER -