This project investigates the effects of a severe arctic storm on community structure and evolution of the mussel, Mytilus califonianus . The storm descended on the Pacific Northwest in late December 1990 and resulted in atypical freezing weather in the intertidal zone inhabited by the mussels. Such events probably occur about once in every twenty five years although there is some evidence of an increase. The mussels were severely affected by the freeze, and large mortalities were observed. However, mortality appears to be non.random. Mussels with other organisms living on and with them, such as barnacles and algae, did not die as often as mussels without associated organisms. This project will document mortality through field collections, and carry out genetic analysis (by the technique of electrophoresis) of survivors and of dead individuals. The results will determine whether genetic and phenotypic changes in the mussel populations will accompany community wide changes, and hence whether evolutionary changes will occur.
