Abstract OPP-9423329 This project takes a novel approach to observing and understanding zooplankton patch dynamics, supported by recent developments in both theory and instrumentation. The species for this research project are the northern boreal euphasiids Thysanoessa raschii, T. inermis and Meganyctiphanes norvegica. These are ideal subject organisms for this study, because much is already known regarding their basic physiology and ecology. Strong diel and seasonal changes in their physiological activity are expected to provide measurable differences in both metabolism and aggregation behavior. The ability to measure such significant differences is important, because the research emphasizes observations of metabolism, using a novel application of bioacoustic technology. This project will explore a new application of the acoustic Doppler current profiler (ADCP), using measurements of Doppler spectral broadening to quantify locomotory activities of these euphasiids in situ. The relationship between locomotion and respiratory metabolism, which is well established for other euphasiid species, will be measured for the three species in the proposed study area of Balsfjorden, northern Norway. This research will provide an assessment of a new, non-invasive method for measuring the in situ metabolic state of macrozooplankton. The results will lead to a better understanding of how locomotory behavior, per se, influences patterns of patch formation, maintenance and dissipation. These findings will be interpreted within the framework of a mew model that describes patch dynamical processes in terms of statistical mechanics. It is expected that new basic knowledge will be added to the understanding of aggregation behavior of the three species of euphasiids that play a central role in Arctic ecosystems.
