title: [Relationship between water transfers and the salinity of the environment in the isopod crustacean Sphaeroma serratum (Fabricius)].
abstract: The isopod Crustacean Sphaeroma serratum is isotonic to the medium in sea water and hypertonic in diluted media. The drinking rate is 15.9 microliter in SW and 3.2 microliter 24 h-1 100 mg-1 wet weight in 50% SW. The extracellular space is 28.4% in SW and 27.0% of the wet weight in 50% SW. The rate of urine production, calculated from the half time for the loss of sodium diatriazoate is 11.8 mg in SW and 42.9 mg 24 h-1 100 mg-1 wet weight in 50% SW. 95% of the diffusion fluxes of water take place through the pleopods: their surface is about 62.6 mm2 in a 100 mg weighing animal. The activation energy of water molecules is 15.0 kcal/mol between +5 degrees C and +15 degrees C and 6.7 kcal/mol between +15 degrees C and +25 degrees C. The diffusion permeability coefficient Pd is 1.71 X 10(-4) cm/sec in SW and 0.70 X 10(-4) cm/sec in 50% SW. The osmotic permeability coefficient Pos has a mean value of 1.91 X 10(-4) cm/sec in SW and 1.24 X 10(-4) cm/sec in 50% SW. Our results are compared with those obtained in other Crustaceans and in Fishes. Their validity is discussed (influence of unstirred layers, solute-solvent interaction). They are explained according to the different theories dealing with the water transit through the membranes.
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D003445:Crustacea / Q000378:metabolism*; D004058:Diffusion; D005110:Extracellular Space / Q000378:metabolism; D007408:Intestinal Absorption; D009994:Osmolar Concentration; D012623:Seawater; D012964:Sodium / Q000378:metabolism; D013696:Temperature; D014882:Water-Electrolyte Balance
chemical_list: D012964:Sodium
vernacular_title: Les transferts d'eau en fonction de la salinité du milieu chez le crustacé isopode Sphaeroma serratum (Fabricius).