QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by PANTIN, C. F. A. Search for Related Content PubMed Articles by PANTIN, C. F. A.

Journal of Experimental Biology 8,82-94 (1931)
Published by Company of Biologists 1931

The Adaptation of Gunda Ulvae to Salinity : III. The Electrolyte Exchange

C. F. A. PANTIN M.A.¹

¹ Zoological Laboratory, Cambridge

1. The rate of loss of salts by the estuarine worm, Gunda ulvae, on transference from sea water to various dilute solutions has been studied by measurement of the electric conductivity of the solutions.

2. Salts are lost by the worms from the moment of immersion in dilute solutions. Conditions affecting the rate of loss of salts are discussed.

3. The relation between the amount of salts lost and the total electrolyte content of the worm was determined. It is shown that the worms only lose 25 per cent. of their salts during the time that they imbibe a volume of water from the dilute solution equal to their initial volume.

4. The limiting internal salt concentration of worms surviving in waters containing calcium is about 6-10 per cent. of the normal concentration in sea water. No such limiting value can be found for distilled water, since salts are lost continuously till cytolysis occurs. The significance of the limiting concentration is discussed.

5. The effect of osmotic pressure, pH, dilute solutions of NaCl, NaHCO₃, glycerol, CaCl₂ and CaCO₃ are studied. The presence of calcium reduces the rate of loss of salts. Other factors do not seem to influence this rate.

6. The relation of calcium to the maintenance of normal permeability to water and salts in the worm, and the significance of this to the problem of migration into fresh water are discussed.