BODY SIZE AND GEOMETRY PREDICT ZOOPLANKTON SURVIVAL TO AIR EXPOSURE

Dormant life stages of freshwater zooplankton are typically resistant to environmental exposure, and this facilitates overland dispersal. However, environmental exposure and overland dispersal are less well understood for active life stages. To characterize empirically the longevity of active life stages out of water, survival time to air exposure was measured in the laboratory for eight cladoceran species using heartbeat cessation to signify survival time. Survival time increased with body dry weight with an allometric scaling exponent near 2/3 for a multispecies model with six bivalved species including Bosmina longirostris, Acroperus harpae, Ceriodaphnia dubia, Daphnia mendotae, Daphnia pulex, and Daphnia magna. The 2/3 scaling exponent is consistent with Euclidean geometry and points to water loss across the surface of a spherical body as the cause. Survival time of a seventh species, Holopedium gibberum, was 571% longer than predictions based on the multispecies model, likely due to its gelatinous mantle. Survival time of an eighth species, Bythotrephes cederströmii, was 68-94% shorter than predictions based on the multispecies model, likely due to its lack of a bivalved carapace. The longest survival time of an individual was 225 min (H. gibberum). We share a conceptual model of how body size may predict overland dispersal potential of zooplankton active life stages.

Presentation Preference: Poster

Primary Presenter: Donn Branstrator, University of Minnesota Duluth (dbranstr@d.umn.edu)

Authors:

Rebecca Smith, University of Minnesota Duluth  (rbeccaasmith@gmail.com)