Scott Cowan Marine and Estuarine Science Program   Department of Biology MSc. Completed Fall 2005 BSc. Eckerd College, 2001

Project

Thesis Title:  The effects of wave force, temperature, and emersion on adhesion time in the limpet, Lottia pelta

Abstract:  Limpets (Family Acmaeidae) are highly successful at coping with life in the intertidal zone due in part to their ability to maintain position on the substratum despite repeated exposure to multiple abiotic stressors.  Two sets of experiments were conducted in the laboratory to determine the effects of multiple abiotic stressors on adhesion time in Lottia pelta.  In the first set, summer- and winter-acclimatized limpets were exposed to treatments consisting of combinations of one of two forces, one of two periods, and one of three water temperatures.  For summer-acclimatized limpets exposed to a 1 N wave force, mean adhesion times at both 8 and 12-second periods were significantly lower at 4  ºC then those at 10 or 16  ºC.   In winter-acclimatized limpets, increasing wave force caused a significant decrease in adhesion time, but no significant temperature effects were found.  The second set of experiments examined the effect of increasing emersion time on adhesion time in both summer- and winter-acclimatized limpets.  Emersion treatments had no significant effect on adhesion time in either treatment group, suggesting that L. pelta is well adapted to periods of exposure in air caused by the daily tidal cycle.  Overall, the results of this study suggest L. pelta is most vulnerable to dislodgement by high magnitude wave forces generated by acute changes in water velocity, and as water temperature drops from 10 ºC to 4 ºC.  This suggests that storm events may be important mechanisms controlling the distribution and zonation of these animals in Bellingham Bay.