Meeting Abstract

S10-9   14:30 - 15:00  Ecomechanics of mussel attachment in a warming ocean: divergent effects on multiple functional traits predict range shifts in two congener species Newcomb, LA; Cannistra1, AF; Carrington, E; University of Washington, Friday Harbor Laboratories ; University of Washington; University of Washington, Friday Harbor Laboratories

Organisms rely on the integrity of the structural materials they produce to maintain a broad range of processes, such as acquiring food, resisting predators or withstanding extreme environmental forces. The production and maintenance of these biomaterials, which are often modulated by environmental conditions, can therefore have important consequences for fitness in changing climates. One well-known example of such a biomaterial is mussel byssus, an array of collagen-like fibers (byssal threads) that tethers a bivalve mollusk securely to benthic marine substrates. Byssus strength directly influences mortality by dislodgement and depends on the quantity and quality (strength, extensibility, stiffness) of byssal threads produced. We compared the temperature sensitivity of byssus strength of two mussel species common to the west coast of North America, Mytilus trossulus and M. galloprovincialis. When exposed to seawater temperatures ranging from 11 to 25?C in the laboratory, we found the two species attached equally strong when below 18?C. Above 18?C, however, byssal thread production rate and quality was greatly reduced in M. trossulus and increased in M. galloprovincialis, causing a 2 to 10-fold difference in byssus strength between the two species. These findings are consistent with the current distribution of the two species along the west coast, and suggest a mechanism by which a northern expansion of M. galloprovincialis could displace native M. trossulus populations.