Ionic regulation in the squat lobsterGalathea squamifera, with special reference to the relationship between potassium metabolism and the accumulation of radioactive caesium

Abstract

The absorption of radioactive Cs from sea water in relation to K metabolism has been examined in the squat lobster Galathea squamifera. A general study has been made of the ability of Galathea to carry out osmotic and ionic regulation as a comparison with better known decapod crustaceans which have previously been used for radioactive Cs experiments.Galathea appears to be a truly marine decapod in that it is probably unable to osmoregulate and the body surface is very permeable to water and to Cs and Kions. Despite this high permeability, Galathea is able to regulate K and radioactive Cs at blood plasma levels which are 1.3 and 1.1 times those of sea water. The Na and Cl concentrations in the plasma are not regulated and the Ca concentration is variable, but Mg and SO4 are maintained at concentrations below those of sea water. Urinary excretion does not assist in the conservation of K or radioactive Cs in the plasma but assists in removing Mg and SO4.