Thermal tolerance of Crepidula fornicata (Gastropoda) life history stages from intertidal and subtidal subpopulations

Abstract

The ability to withstand high summer temperatures is an extremely important determinant of species distributions in the intertidal zone; most marine organisms cannot live intertidally because of the harsh conditions experienced during aerial emersion. The members of some species, though, live both intertidally and subtidally, and their physiological tolerance to stressors may differ depending on their genetic connectivity, acclimatization, and differential post settlement mortality. Furthermore, tolerances of organisms at different life-history stages within both habitats may differ and will play an important role in determining adult distributions. To determine the effect of habitat and life-history stage on physiological tolerance and the likely contribution of upper thermal tolerance limits to the native distribution of an important invasive species, the slippershell snail Crepidula fornicata, we compared the thermal tolerance of intertidal and subtidal embryos and adults in relation to conditions that they experience in the field. We found C. fornicata living both intertidally and subtidally in Bissel Cove, Rhode Island, where they experienced drastically different thermal conditions. Intertidal individuals achieved body temperatures as high as 42°C, more than 15°C higher than those recorded in subtidal conspecifics. However, subtidal individuals had remarkably high thermal tolerances that were nearly identical to those of intertidal conspecifics (lethal range = 33−37°C following a 3 h exposure). Furthermore, embryos were even more tolerant to high thermal stress than adults. These results are surprising: the few previous studies that have compared thermal tolerances among individuals at different life-history stages have found differences among them, and early stages are generally more sensitive than adults. Interestingly, the markedly higher temperatures that intertidal animals experienced in this study had little effect on their thermal tolerance. Intertidal (but not subtidal) slippershell snails are now living dangerously close to their upper thermal limits and will almost certainly be relegated to the subtidal as global temperatures rise.

Differences in feeding adaptations in intertidal and subtidal suspension-feeding gastropods: studies on Crepidula fornicata and Crepipatella peruviana

“…The gradients of stressors most closely associated with intertidal life are usually linked to environmental heterogeneity from aerial exposure: when compared to subtidal organisms, intertidal organisms experience periodic exposure to desiccation (e.g., Garrity 1984) and to hypoxia (e.g., Brinkhoff et al 1983), rapid changes in salinity (especially in tide pools-e.g., Morris and Taylor 1983), and greater and more rapid temperature fluctuations (e.g., Diederich and Pechenik 2013). However, sessile suspension-feeding invertebrates, such as those investigated in the present study, are at an added disadvantage if they live intertidally, as they are unable to feed while exposed to the air.…”

“…However, our experiments were performed at cooler temperatures than in Chaparro et al (2002), and C. peruviana in our study were first removed from their substrates and transferred to plastic plates, both of which may have contributed to the slower particle velocities that we found. The intertidal zone is a particularly stressful place to live (e.g., Brinkhoff et al 1983;Morris and Taylor 1983;Garrity 1984;Petes et al 2007;Harley et al 2009;Miller et al 2009;Diederich and Pechenik 2013) for sedentary marine organisms, and physiological stress has previously been associated with reduced performance (i.e., feeding rate) in some marine invertebrates (Abel 1976;Menge 1978;Widdows et al 1981;McCormick et al 1998). The pattern of CR and particle velocity transport across the gill in addition to the pattern of size distribution (subtidal > intertidal) in C. peruviana suggests that intertidal individuals could be stressed in relatively poor physiological condition.…”

“…For all experiments, specimens of C. fornicata were collected from Bissel Cove, Rhode Island, USA (41.549920, −71.430584), where they can be found both intertidally and subtidally in large numbers (Diederich and Pechenik 2013). Collections were made for studies of gill morphology on April 20, 2011 and for clearance rates (CR) on May 22, 2012.…”

“…Though some marine species are only found subtidally (e.g., Tomanek and Somero 1999;Collin 2000;Stillman and Somero 2000), and some are found chiefly in the intertidal zone (e.g., Connell 1972;Perez et al 2009;Bourdeau 2011), a number of species are abundant in both areas (e.g., Dame 1972;Fletcher 1984;Saier 2002;Schaffmeister et al 2006;Dong et al 2011;Diederich and Pechenik 2013) and so experience a remarkable range of Abstract Suspension-feeding organisms living in the intertidal zone experience reduced feeding times associated with periodic aerial exposure. The potential morphological and physiological adaptations to this reduced feeding time were investigated for two closely related gastropods, Crepidula fornicata and Crepipatella peruviana.…”

“…The closely related calyptraeid gastropods Crepidula fornicata (native to the east coast of North America) and Crepipatella peruviana (formerly Crepipatella fecunda, native to the Chilean coast) live both intertidally and subtidally (Gallardo 1979;Collin 2003;Diederich and Pechenik 2013). These gastropods eat by collecting particles from the water using their modified gill (ctenidium) and transporting those particles to a food groove, where they are concentrated, directed to the mouth (via the food groove in the neck), and ingested .…”