(full paper is archived in the Miller Library)
Title: Morphological and mechanical responses to wave-induced drag in Mastocarpus papillatus (Rhodophyta)
Student Author(s): Kitzes, Justin
Faculty Advisor(s): Denny, Mark
Location: Final papers biology 175H
Date: June 2003
Abstract: Intertidal algae are exposed to potentially severe environmental forces on a daily basis. One of the most important of these is the pressure drag generated by crashing waves, the magnitude of which is determined by the interaction of water velocity and an alga’s projected area. This study addresses the effects of increasing drag on the properties of the common intertidal red alga Mastocarpus papillatus. Breaking force of the stipe is positively correlated with drag, indicating morphological and/or mechanical differences between exposed and protected individuals of this species. Contrary to preliminary work by Carrington (1990), stipe cross-sectional area and material strength are both positively correlated with drag as well as with breaking force, suggesting that an individual blade may be adjusting both of these parameters in response to its mechanical environment. A single blade does not, however, appear to increase both of these factors simultaneously, as stipe cross-sectional area and strength are negatively correlated. Thus I find that M. papillatus may respond to increased drag by either increasing its stipe diameter or its tissue strength but not both together. The range of variation in these two properties, however, remains small when compared to the overall natural variability within the population.
Notes: Published in Biological Bulletin, 2005 208:114-119