P2.92 Thursday, Jan. 5 Combined effects of temperature and hydrostatic pressure on the early ontogeny of the common whelk Buccinum undatum (Linnaeus, 1758) SMITH, K E*; THATJE, S; University of Southampton; University of Southampton Kathryn.Smith@noc.soton.ac.uk
The dispersal and migration of marine fauna are affected by many factors; two of which to be considered significant are temperature and hydrostatic pressure. To understand the necessary evolutionary adaptations for colonisation of different thermal and hyperbaric environments it is important to understand how these factors affect not only adults, but also early life stages. Here we examine how these variables impact veligers and juveniles of the neogastropod Buccinum undatum. Development in this species is intracapsular. Successful development was observed at temperatures from 6 to 18°C. In veligers, temperature negatively affected respiration rates but no effect of pressure up to 400 atm was seen. In juveniles, respiration rates were affected by temperature, pressure and the interaction of the two. The greatest tolerance to high pressure was seen at the lowest experimental temperature (6°C). Behavioural studies indicated both veligers and juveniles could survive pressures equivalent to 3000m water depth (300 atm). The temperature and pressure tolerances observed are outside the bathymetric and latitudinal range of B. undatum’s current distribution, which may suggest this species is capable of further expanding its distribution range. The increased pressure tolerance seen with decreased temperature in juveniles may be linked to the deep-sea origin of neogastropods. This study highlights the importance of understanding the full effects of temperature and pressure across all ontogenetic stages. Without this knowledge it is impossible to understand better how changes in climate envelopes affect the distribution and radiation of species.