Wang, SichengCasendino, Helen2021-08-232021-08-232021http://hdl.handle.net/1773/47163As biogenic habitat, N. luetkeana beds mediate interactions between the abiotic environment and biological dimensions of an ecosystem. Prevalent in existing literature is evidence for relationships between N. luetkeana blade morphology and flow velocity of the surrounding environment. In our project, we examined the effect of contrasting flow velocities on blade morphology of N. luetkeana from the San Juan Islands, WA, and further how blade thickness varied based on the blade’s spatial characteristics. We also examined how flow regime and consequent blade morphology affects rates of herbivory via the kelp crab (Pugettia producta). Our results show that blades are thickest near their midline (lengthwise), and that blades closest to the central axis are thicker than those further away. Trends in linear models of our data indicate that blades exposed to higher flow velocities were narrower and less undulated than their low flow counterparts, which is consistent with existing literature. Our results show that kelp crabs preferred blades from an area of relatively high flow velocity. One explanation for this result is that narrow, flat blades are mechanically easier for kelp crabs to consume than wide, undulated blades. It is possible that the wide, undulated blade morphology is a morphological defense against herbivory for blades that experience low flow velocity, where kelp crab herbivory may be more prevalent. More research is needed to determine if blade morphology mediates the interaction between flow velocity and herbivory.Pugettia producta