Aerial exposure and body temperature of the intertidal sea anemoneAnthopleura elegantissima

Abstract

The sea anemone Anthopleura elegantissima is a common member of intertidal communities along the west coast of North America, and can experience extended periods of increased temperature during summertime low tides. Internal body temperatures of emersed individuals of A. elegantissima were monitored in a laboratory wind tunnel and in the field, and factors influencing the anemones' thermal experience were examined. Larger body size and aggregation with conspecifics slowed body temperature increases in controlled wind tunnel conditions. In the field, anemones in the interior of an aggregation stayed cooler than those on the edges, and microhabitat features related to light exposure and surface orientation overshadowed any direct effects of body size. In the warmest month only (July), aggregations of A. elegantissima were significantly larger at the upper limit of their distribution than they were at the mid and lower limits, suggesting aggregation in high intertidal zones may be a behavioral response to desiccation and temperature stress. As this sea anemone can host multiple species of symbiotic algae with different thermal tolerances, the ability to slow body heating may affect the type of algae hosted and thus the potential contribution of this abundant anemone to primary production in the intertidal zone.

Sensitivity to oxidative stress is not a definite predictor of thermal sensitivity in symbiotic dinoflagellates

“…In addition, these two Symbiodinium types/strains experience intertidal environments with highly variable irradiance and temperature regimes (Muller-Parker and Davy 2001). Survival under such conditions is consistent with the stress tolerance seen in this and other studies (Wicks et al 2010;Bingham et al 2011). That different Symbiodinium types, including within the same clade, exhibit different responses to stress is well known (Warner et al 1999;Tchernov et al 2004;Sampayo et al 2007), and it is not surprising that corals and their symbionts growing in higher-latitude environments should cope better with relatively variable conditions (Wicks et al 2010).…”

Symbiont physiology and population dynamics before and during symbiont shifts in a flexible algal‐cnidarian symbiosis

“…In our experiment, the simulated intertidal regime combined with the shading treatments exposed anemones to a gradient of irradiance and temperature similar to what they would naturally experience in sunlight‐exposed microhabitats along a vertical gradient in the intertidal zone (Bingham et al. , Dimond et al. ).…”

Symbiotic state influences life-history strategy of a clonal cnidarian

“…Cloning may also decrease the risk of extinction for individual genotypes in these high stress locations where clonal diversity is low and successful sexual reproduction may be infrequent [31,38]. Aggregation of cloned individuals can reduce the costs of a high surface to volume ratio associated with smaller body size by reducing air drying and causing individuals to warm more slowly during low tides [39], allowing the clone to extend outward from protected crevices onto open rock where conditions would be too harsh for isolated individuals [31]. By supporting a shift towards clonal replication, S. muscatinei may contribute critically to the abundance and persistence of A. elegantissima, and indeed itself, in upper shore habitats along much of the North American Pacific coast.…”