Meeting Abstract

55.4  Saturday, Jan. 5  How strong are flow-mediated interactions among neighbouring barnacles? NEUFELD, Christopher J*; PALMER, A Richard; Univ. of Alberta and Bamfield Marine Sciences Centre chris.neufeld@ualberta.ca

On rocky shores, water movement varies dramatically in space and time and influences the ecology and form of many organisms. For example, both size and form of barnacle feeding legs vary significantly with flow conditions. Furthermore, preliminary results suggest crowded barnacles produce longer legs than nearby, sparsely distributed ones. Because leg length is highly plastic, barnacles either a) compete for food (longer legs allow better access to food in an aggregation), or b) alter the flow regime of adjacent barnacles (nearby barnacles reduce water velocities, which causes longer legs to grow). To test for flow-mediated interactions between nearby individuals, I used PIV (particle image velocimetry) to quantify microflow patterns around barnacles (Balanus glandula) growing in different densities. I also performed laboratory experiments to determine ingestion rates of crowded and uncrowded barnacles. I found intriguing differences in the flow patterns and ingestion rates between density treatments. This study documents a novel role for flow-mediated processes in shaping interactions among barnacles and suggests that factors other than direct competition for space can be important in determining the distribution and abundance of organisms in the rocky intertidal.