Meeting Abstract
38.1 Monday, Jan. 5 The spatial and temporal patterns of odors sampled by lobsters and crabs in a turbulent plume REIDENBACH, M. A.*; KOEHL, M. A. R.; Univ. of Virginia; Univ. of California, Berkeley reidenbach@virginia.edu
Odor molecules are dispersed across marine habitats by turbulent water flow, and the spatial pattern of odor concentrations in the water varies with distance from the source. Many crustaceans, such as lobsters and crabs, take discrete samples of these odors by flicking their olfactory antennules. The objective of this study was to assess the odor concentrations sampled by the spiny lobster, Panulirus argus, and the blue crab, Callinectes sapidus, when they flick their antennules to determine if the concentration information they capture at different positions in a turbulent chemical plume can indicate their position relative to an odor source. An odor plume labeled with a fluorescent dye was released from a point source in a 25 m long water flume. Visualization of the odor field at multiple downstream and cross-stream distances from the source, and under various flow conditions were made using planar laser-induced fluorescence, while the velocity vector field was measured using particle image velocimetry. We sampled these odor concentration fields using the kinematics of antennule flicking by the long antennules of P. argus and the short antennules of C. sapidus. On the scale at which antennules sample an odor plume, filaments of high concentration are surrounded by odor-free water. We found that that as crabs and lobsters get closer to the source, the odor intermittency (i.e. on-off temporal signal) and peak concentration increase, but as the organism gets closer in the cross-stream to the plume centerline, intermittency decreases without a statistical change in the concentration sampled. Both crab and lobster antennules sample these concentration and intermittency differences that indicate position in a plume, but only the long lobster antennules sample odor filament width.
