GOOD YEARS AND NOT-SO-GOOD YEARS: PATTERNS IN FALL EGG PRODUCTION BY CLADOCERAN ZOOPLANKTON OF FLOODPLAIN PONDS (BLACK FORK OF THE MOHICAN RIVER, OH)
We are investigating the dynamics of zooplankton in shallower, temporary ponds of a forested floodplain vs. nearby permanent ponds that are inundated year-round. We previously found that total summer-fall precipitation, though highly variable among years, increased significantly over 6.5 decades. We also found that for more temporary ponds, fall zooplankton are much more abundant in dry vs. wet years; in more permanent ponds, overall abundances are relatively high in dry and wet years. This study focused on wet and dry years for both pond types. Do hydrologic differences correlate with differences in zooplankton resources? Size-specific clutch size (SSCS) serves as an index of resource availability. We measured individual body length and clutch size for two cladoceran genera (Simocephalus, Daphnia) with high potential egg production. In the wet year, Simocephalus egg production in the temporary pond was very low until an increase in early December (SSCS = 10 per 1.5 mm indiv.), similar to the abundance pattern. In the dry year, SSCS was high in early fall for both pond types. Patterns in SSCS differed between pond types and between dry and wet years, possibly contributing to differences in zooplankton abundance.
Patricia A. Saunders (Primary Presenter/Author), Ashland University, firstname.lastname@example.org;
Rosalie Sepesy (Co-Presenter/Co-Author), Ashland University, email@example.com;