Meeting Abstract
Physiological intolerance of environmental stress constrains a species’ range by limiting population growth and dispersal to new habitats. Abiotic stress also serves as a barrier to establishment of non-native species. Understanding the interactive effects of temperature and oxygen on aquatic habitats is critical to predicting habitat availability across present and future landscapes. The invasive snail, Potamopyrgus antipodarum, tolerates diverse abiotic conditions across its global distribution, but how habitat temperature and oxygen availability interactively affects its distribution is unknown. This study investigated the effect of water temperature and oxygen saturation on respiration rate to discern under what conditions persistence would be limited. We predicted that respiration rates would increase with temperature and that respiration rates would decrease with decreasing oxygen supply. Respiration rates were measured during progressive hypoxia, from 100% O2 until respiration ceased, at 9 temperatures (7-35°C). As predicted, we found that respiration rates declined with decreasing water temperature and decreasing oxygen availability. At warmer temperatures snails continued respiring under increasingly hypoxic conditions (<1.5mg/L O2) while they stop earlier at lower temperatures (1.5-3 mg/L O2). Thus, faster respiration rates were associated with a more complete use of available oxygen. At low temperatures there is still oxygen remaining suggesting that snails have stopped respiring through active regulation rather than conforming respiration rates to the oxygen supply available. However, at high temperatures the only option is to use the remaining oxygen.
