Intra- and interspecific variability in tolerance of Southern California Littorina planaxis and Littorina scutulata to petroleum

Abstract

The present study was designed to investigate the inter- and intraspecific responses of Southern California Littorina planaxis and Littorina scutulata from coastal and island sites when exposed to gasoline, kerosene, Santa Barbara crude oil, Kuwait crude oil, and a Louisiana crude oil, under laboratory conditions. Variations in tolerance of Littorina to different petroleum at 6, 17, and 29°C, as indicated by mortality rate and rate of animal attachment to the substrate, were observed. Differences in animal size, composition of the petroleum, and the natural habitat of the animals were considered. The attachment rate of Littorina varied with temperature, but not in a consistent way for different petroleum, localities, or species. The most consistently high rate of attachment for both species occurred at 17°C. While L. scutulata exhibited a greater tolerance to various conditions at 6°C, L. planaxis had a greater tolerance at 29°C. The only mortalities occurred at 29°C. The mortality rate varied with the type of petroleum used and appeared to be size and species related. Gasoline had the greatest influence on attachment rates at all temperatures, and kerosene had the least effect on attachment rates. There was no consistent attachment rate trend among crude oils; however, their influence was intermediate between that of gasoline and kerosene.