Introduction to Marine Biology 4th Edition by George Karleskint,Richard Turner,James Small

Exercise 7

T o tolerate high temperatures and desiccation, rocky intertidal molluscs use such adaptations as large globular bodies that expose less surface area to heating, light-colored shells, beads on the shells that act like radiator fins for cooling, attachment to the surface by mucous threads rather than the foot, adaptations of the kidney, and active orientation of their bodies to minimize sun exposure. Mobile animals move closer to the water or hide in crevices as the tide retreats. Barnacles and mussels close their shells to trap water, allowing it to evaporate slowly for cooling. Rockweeds produce a gelatinous coat to lessen water loss through desiccation.