Journal Article

Calorimetric Studies of Behavior, Metabolism and Energetics of Sessile Intertidal Animals

Shick, J. Malcolm, Gnaiger, Erich, Widdows, John

1988

Overview

Behaviors to conserve water during intertidal exposure at the same time impair respiratory gas exchange, so that observed responses to emersion may reflect compromises between these incompatible needs. Behavioral isolation of the tissues from air results in the complete or partial reliance on anoxic energy metabolism, which is most reliably measured directly as heat dissipation. Combined direct calorimetry and indirect calorimetry (respirometry) enable the partitioning of total metabolic heat dissipation into its aerobic and anoxic components, which may vary according to physical and biological factors. The mussel Mytilus edulis is tolerant of anoxia and saves water and energy during aerial exposure in its rocky intertidal habitat by closing its shell valves and becoming largely anoxic. Like most suspension feeders in this habitat, its compensation for reduced feeding time involves energy conservation; there is little evidence for energy supplementation such as increases in feeding rate or absorption efficiency. Ammonia production continues during aerial exposure and is involved in acid-base balance in the hemolymph and mantle cavity fluid. Infaunal cockles (Cardium edule) and mussels (Geukensia demissa) gape their shell valves, remain largely aerobic and have high rates of heat dissipation during intertidal exposure, a response which appears related to the lower desiccation potential and exploitation of richer trophic resources in their soft-sediment habitats. The variable expansion of the symbiotic sea anemone Anthopleura elegantissima reflects interaction among the responses to desiccation, irradiance and continued photosynthesis by its zooxanthellae during exposure to air.

• Publisher: American Society of Zoologists,Society for Integrative and Comparative Biology
• Subject: Ammonia / Animal and plant ecology / Animal, plant and microbial ecology / Animals / Anoxia / Autoecology / Biological and medical sciences / Energy metabolism / Fundamental and applied biological sciences. Psychology / Geukensia demissa / Heat dissipation / Marine / Mechanisms of Physiological Compensation in Intertidal Animals / Metabolism / Mollusks / Mussels / Mytilus edulis / Oxygen / Oxygen consumption / Oxygen requirement / Protozoa. Invertebrata