(full paper is archived in the Miller Library)
Title: Individual stipe strength of Macrocystis pyrifera
Student Author(s): Hagberg, Theresa
Faculty Advisor(s): Pearse, John
Location: Senior Thesis UC Santa Cruz
Date: April 1994
Abstract: We hypothesize that a kelp plant adapted to lessen the stipe strength prior to winter storms resulting in canopy removal which increases the probability of survivorship of the entire kelp plant. To test this hypothesize we measured the stipe strength of Macrocystis pyrifera, this study mesured the stress needed to break an individual stipe in the winter season and compared it to the summer season. The following observations were made: (1) Less stress is needed to break a piece of kelp in the winter than in the summer. (2) The diameter of the kelp stipe may or may not be a factor affecting the stress needed to break the kelp stipe. (3) The length of the kelp frond is not a factor affecting the stress needed to break the kelp stipe. (4) The kelp stipe stretches 1/4-1/3 of its original length before it breaks. In the ocean the hydrodynamic forces; drag, lift, buoyancy, and acceleration play key roles which affect the kelp forest community. Many physical and biological processes active in nature were unaccountable for in this experiment.