Grant: Research Tools and Instruments - Category 1 (<$150,000)

The rocky intertidal zone is a hydrodynamically stressful habitat, where breaking waves impose tremendous drag forces on intertidal inhabitants. Despite this adversity, wave-swept seaweeds thrive under these conditions, successfully producing a wide range of morphologically diverse fronds that "go with the flow," bending over and changing shape to reduce drag. However, our understanding of the drag force experienced by seaweeds and the behavior of flexible fronds in the surf has been limited by our ability to recreate high-speed environmentally-relevant flow in the lab. The funding requested in this proposal is to purchase a high-speed recirculating water flume that generates experimental velocities up to 4 m/s. The proposed flume is constructed of clear acrylic to enable the visualization of test specimens at all flow velocities. Force transducers and digital cameras mounted to the proposed flume will thereby permit researchers to simultaneously quantify drag force and behavior of flexible fronds at high speed. These data will be used to estimate mechanical limits to size and growth of intertidal seaweeds and to explore the selective role of drag in the evolution of seaweed morphology. In addition, the proposed flume will be used by researchers studying the swimming performance of fish in extreme flow and the biomechanics of feeding in baleen whales.