Riders on a Shell: The Effect of Algal Epibionts on Eagle Cove Limpets

Abstract

Limpets and algal epibionts develop mutually beneficial associations. This study examines the benefits of green algal epibionts on the limpet Lottia pelta at Eagle Cove. Density of algal cover was compared between populations of limpets at the middle and low regions of the intertidal zones. Temperature differences between limpet populations with varying degrees of epibiont cover and the adjacent rock were analyzed. Previous work in vitro suggested that a high epibiont density on a limpet shell acted as a shield against thermal stress. The results of this study showed that limpet shell surface temperature cannot be correlated with the observed epibiont density. These results supported the hypothesis that when the temperature of limpets is measured in situ, epibiont density does not necessarily provide heat tolerance adaptation by the host. This study showed no significant difference between the means of the limpet temperature at middle and low regions and no significant difference between the temperature of the limpet and its adjacent substrate, regardless of region or moisture of the substrate. This supports the hypothesis that epibiont density on a limpet does not reflect the immediate substratum and suggests that live limpets can manage heat stress. The green algae sampled from the limpets collected in this study were classified as Ulva prolifera, and other Ulva sp., Ulothrix. Sp., Acrosiphonia sp., and Blidingia dawsonii. This study highlights interspecies mutualistic associations and their possible role in limpet adaptations to heat stress. Further studies will include analyzing diverse limpet species, algal epibionts and sample sites.