Oxygen consumption in six species of chitons in relation to their position on the shore

Abstract

Aerial and aquatic oxygen consumption rates have been measured in six species of intertidal chi tons with respect to zonation, size and oxygen concentration of the external medium. Those species occurring highest on the shore were found to have a lower rate of aquatic oxygen consumption than those ~i'eeies occurring lowest on the shore, with mid-shore species showing intermediate rates. Aerial oxygen consumption rates were similar in most species and were not strictly correlated with their position on the shore. High shore chitons had higher or equal rates in air than in water, while low shore species had higher aquatic than aerial rates. It was also found that the six species could be grouped with respect to their oxyregulatory capabilities when exposed to declining oxygen tensions and these groups could be correlated with the species intertidal zonation: high shore species show a high degree of oxygen independence, mid-shore species a moderate degree and low shore animals little or no regulatory capabilities.