1. Introduction
Organisms that inhabit the intertidal zone are usually exposed twice
daily to the air, where they are faced with the problem of oxygen consumption,
carbon dioxide removal and maintaining acid–base balance
(deFur, 1988). Many of the organisms that inhabit the intertidal zone
possess some mechanism that allows continued oxygen consumption,
however there may be challenges associated with the removal of carbon
dioxide (deFur, 1988; Newell, 1973). Coupled with changes in the respiratory
medium, intertidal zone animals often have to deal with sharp
changes in temperature. Because of its higher thermal inertia the
ocean remains relatively stable over a tidal cycle, however animals can
be subject to abrupt changes of up to 20 °C occurring both when exposed to air and upon re-immersion. These rapid changes in temperature
are a defining factor affecting the physiology of intertidal organisms
(Helmuth and Hofmann, 2001).