ZOL 353 Lecture 36: Lec 36-Tidelands – Rocky Shores and Exposed Beaches
Document Summary
General pattern of temperate and boreal rocky shore zonation: protected vs. wave-swept waters in the same spot differ in assemblages. The challenges faced by intertidal zone organisms: the intertidal is alternately marine, then terrestrial 2x/day, when exposed, intertidal organisms not in tide pools face, heat stress, desiccation, bright sun, shortage of oxygen, more exposure higher up. High-intertidal vs. low-intertidal: upper intertidal (ui) animals are adapted to function at higher temperatures than lower (li) ones, ui barnacles beat cirri more often at much higher temperatures than li. Genetic variation in shell color: mytilus edulis has genetically determined shell color morphs. Light shells reflect heat so overheat less: selected for and dominant in south, dark shells absorb heat so function better in cold, selected for and almost universal in north. Some use sun as cue: some ui gastropod littorina neritoides use combination of sun, immersion, and body angle as cues to determine where or if to move.
