3.1 Wednesday, Jan. 4 Comparative physiological energetics of the blue mussel species in response to increased temperatures FLY, E.K.*; HILBISH, T.J.; University of South Carolina; University of South Carolina email@example.com
The three species of the blue mussel complex are distributed worldwide, but differ biogeographically with respect to temperature. Mytilus galloprovincialis is sub-tropical, while M. edulis and M. trossulus are cold-temperate and boreal, respectively. We examined whether these sister-species show physiological differences with respect to temperature, as is suggested by their global distributions. We hypothesized that the warmer-water species, M. galloprovincialis, has an advantage at higher temperatures than M. edulis and M. trossulus, in terms of maintaining a positive energy budget. We measured respiration rates, absorption efficiencies, and clearance rates of all three species at a range of temperatures (5, 10, 15, 20, 25, and 30°C) in both summer and fall. Mytilus galloprovincialis has a greater physiological advantage at high temperatures than the other two species. Of the three physiological variables measured, clearance rate is the driving force in determining each species’ energy budget, and M. galloprovincialis maintains higher clearance rates at warmer temperatures than the other species. Thus, M. galloprovincialis maintains a positive scope for growth through 25°C, while M. edulis shows negative scope for growth at 25°C, and M. trossulus shows negative scope for growth values at 15°C and higher. The physiological advantage seen in M. galloprovincialis is expected to be a factor in the advance of this species into the colder-water species’ habitat with warming water temperatures.