Mussel attachment in a warmer, high-CO2 world: an ecomaterial approach

Mussels are key aquaculture species and often dominate  temperate rocky shores worldwide, forming dense aggregations firmly tethered by  byssal threads-extracellular fibers molded by the mussel foot. Field studies with Mytilus spp. have shown byssus strength, or tenacity, follows a  strong seasonal cycle, rendering both wild and farmed populations prone to "fall-off" in late summer/early fall when increased storm activity coincides  with weak attachment.  Seasonal weakening  is due primarily to environmentally-induced changes in the material properties  of individual byssal threads. Using custom laboratory mesocosms, we quantified  the effects of two common environmental stressors, elevated temperature and pCO₂ (= acidification), on  the mechanical performance of byssal threads in M. trossulus.  Both stressors  caused thread weakening and loss of extensibility, but targeted different  regions of a thread. These results suggest multiple environmental stressors,  including ocean acidification and warming, can combine to critically compromise  the structural integrity of mussels.

Speaker: Emily Carrington, Ph.D., Univ. of Washington