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Publisher Summary This chapter reviews the aerobic and anaerobic energy metabolism of Littorina species in relation to the pattern of intertidal zonation. In the intertidal area along the coast of Brittany, France, closely related Littorina species have their habitats at different levels of the shore. The species living at the low tide level zone are exposed to air for short periods only and may be protected against large variations in environmental conditions by Fucus or other sea weeds, stones, or rock pools. However, the species living near the high spring tide level may be exposed to air for weeks in an environment where thermal and desiccation stress are common. The species living in the upper part of the intertidal zone have a structural adaptation, that is, a reduced gill size, that makes the mantle cavity to assume a lung function. Thus, these species presumably are more adapted to breathing in air than their lower living relatives. Changes in salinity in the intertidal zone occur in estuaries or by rain fall. One of the strategies many molluscs exhibit to avoid harsh conditions is the withdrawal into the shell that can provoke anoxic conditions. The chapter discusses a study that was undertaken to find a possible relationship between the intertidal zonation pattern of five Littorina species, namely, L. nerotoides, L. rudis, L. nigrolineata, L, littorea, and L. obtusata, and the capabilities for oxygen uptake in water and air, and the capability to metabolize anaerobically. The results of the study showed no advantages for these species during exposure to air over the animals with a unmodified gill. |
