Respiration in air and water of four mediterranean trochids

Abstract

The oxygen consumption of inactive animals of four species of Mediterranean trochid was measured in air and sea water at temperatures commonly recorded on the shore. The loss of mantle cavity fluid significantly lowered the aerial oxygen consumption of all four species. The aquatic oxygen consumption of the four species after 12 h settlement in the respirometer was not significantly different from that measured after 1 h. The high-shore Monodonta lurbinata (Born) and M. articulata (Lamarck) experience a maximum of 60 to 70% aerial exposure, wide temperature fluctuations, and can maintain an aerial rate of oxygen consumption similar to the aquatic rate. They have temperature dependent rates of oxygen consumption with similar Q 10 values in both air and water between 20 and 30°C. The low-shore Gibbula richardi (Dayraudeau) and G. rarilineata (Michaud) are characterized by a low maximum percentage aerial exposure, a more stable thermal environment, an aerial rate of oxygen consumption lower than the aquatic rate, temperature dependent respiration rates between 20 and 30°C in sea water but a temperature coefficient not significantly different from 1 in air. These patterns of oxygen consumption are reflected in the 50% survival times of the trochids in air at 25°C. The pattern of respiration in air and water of a wide range of intertidal gastropods has been related to the maximum percentage aerial exposure experienced on the shore.