Meeting Abstract

71.2  Friday, Jan. 6  Can waterborne settlement cues trigger the larval transition from the plankton to the seafloor? ARELLANO, Shawn M.*; MULLINEAUX, Lauren; ANDERSON, Erik J.; HELFRICH, Karl; MCGANN, Brenna J.; WHEELER, Jeanette D.; Woods Hole Oceanographic Institution; Woods Hole Oceanographic Institution; Grove City College; Woods Hole Oceanographic Institution; Grove City College; Woods Hole Oceanographic Institution

In marine benthic species, populations are connected via transport of their swimming larvae. The swimming behaviors that trigger the larval transition back to the seafloor are not understood well. One possibility is that waterborne cues originating from a settlement surface may mix up into the water column where swimming larvae can respond to them. Substratum-bound and waterborne chemical cues that induce larval settlement in late-stage barnacle larvae (cyprids) are characterized well. While substratum searching behaviors and settlement selection in response to these cues have been described, experiments examining the effects of waterborne cues on larval swimming behaviors under natural flow conditions are rare. We are using digital video observations, larval tracking, and flow characterizations to examine how cyprids respond to waterborne cues in field-relevant turbulent conditions. Preliminary experiments in still-water containers suggest that the average cyprid vertical swimming velocity switched from upward to downward when a homogenously dissolved waterborne cue was present. Subsequent experiments in a large racetrack flume examining changes in vertical swimming behaviors (e.g., velocity, tortuosity, sinking rate) as larvae come into contact with filaments of cue in turbulent flow will also be presented.