Meeting Abstract
As ocean temperatures steadily rise, marine species will be exposed to temperatures that are increasingly over their physiological optima. In order to anticipate species’ responses to rising temperatures, we need to know the relationship between metabolic rate and thermal history, which itself may vary at small-scales in space and time. We measured metabolic rates of hermit crabs (Pagurus hirsutiusculus) and mussels (Mytilus trossulus) and evaluated the relationship between thermal sensitivity and thermal history. Organisms were collected from 24 tide pools in Sitka, Alaska in which we also recorded temperature every five minutes for three months prior to metabolic rate assays. Using respirometry, we estimated resting mass-specific oxygen consumption (MO2) at three different temperatures (10°C, 18°C, and 26°C) for one hermit crab and one mussel from each tide pool at three seasonal time points. We tested for linear relationships between thermal sensitivity (individual MO2 slopes) and the following environmental parameters: average, variance, maximum, minimum, and range of pool temperatures. For both species, there were relationships between thermal sensitivity and thermal history; however, the direction of the relationships and most important thermal parameters differed between species and seasons. These findings show that thermal environmental history at small scales strongly influences metabolic response to temperature increase within populations and in ways that differ notably between species and seasons.
