Effects Of Crustaceans

Register to read the introduction… As a rule, the gill area is greater in fast-moving crabs (Portunids) than in sluggish bottom dwellers; decreases progressively from wholly aquatic, to intertidal, to land species; and is greater in young crabs than in older crabs. Often the gills are enclosed in protective chambers, and ventilation is provided by specialized appendages that create the respiratory current. As in cephalopod mollusks, oxygen utilization is relatively high—up to 70 percent of the oxygen is extracted from the water passing over the gills in the European crayfish Astacus. A decrease in the partial pressure of oxygen in the water elicits a marked increase in ventilation (the volume of water passing over the gills); at the same time, the rate of oxygen utilization declines somewhat. Although more oxygen is extracted per unit of time, the increased ventilation increases the oxygen cost of breathing. The increased oxygen cost, together with the decrease in extraction per unit of volume, probably limits aquatic forms of crustaceans to levels of oxidative metabolism lower than those found in many air-breathing forms. This is largely due to the lower relative content of oxygen in water and the higher oxidative cost of ventilating a dense and viscous medium compared with air. Not all crustaceans meet a reduction in oxygen with increased ventilation and metabolism. The square-backed crabs (Sesarma) become less active, reducing their oxidative metabolism until more favourable conditions …show more content…
Hughes, Comparative Physiology of Vertebrate Respiration, 2nd ed. (1974); Rufus M.G. Wells, Invertebrate Respiration (1980), a short but useful study; F. Reed Hainsworth, Animal Physiology: Adaptations in Function (1981), which includes chapters on respiration, circulation, temperature, and energetics and their interplay; William S. Hoar, General and Comparative Physiology, 3rd ed. (1983), in which phylogeny in animal functions is used as a framework for depicting animal physiology; Martin E. Feder and Warren W. Burggren, “Skin Breathing in Vertebrates,” Scientific American, 253(5):126–142 (Nov. 1985); Knut Schmidt-Nielsen, Animal Physiology: Adaptation and Environment, 3rd ed. (1983), which explains systematically how animals cope with their environments; and a supplement to it, C. Richard Taylor, Kjell Johansen, and Liana Bolis (eds.), A Companion to “Animal Physiology” (1982), which probes certain topics, including respiratory physiology. See also V.B. Wigglesworth, The Principles of Insect Physiology, 7th ed. (1972, reprinted 1982), an excellent introduction to the form and function of insect respiration. C. Ladd Prosser, “Oxygen: Respiration and Metabolism,” ch. 5 in C. Ladd Prosser (ed.), Comparative Animal Physiology, 3rd ed. (1973), pp. 165–211, is a comprehensive chapter on oxygen and its role. Charlotte P. Mangum, “Oxygen Transport in Invertebrates,” The American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, 248(5):R505–R514 (May 1985), provides a succinct overview of oxygen-carrying