The contribution of dissolved amino acids to the nutrition of articulate brachiopods

Abstract

It has been a:rgued that dissolved organic oompounds are utilised by articulate braohiopods, and that regional patterns in the distribution and abundance of these animals may reflect the nutrient content of the sea walters. This hypothesis was tested by exposing Terebratella inconspicwa to dilute solutions of radioactively labelled glycine arrd glutamic acid. Individuals of T. inconspicua accurnuIate amino acids, apparently through one or more active transport systems localted in the surface epithelium. The rate of uprtake of the molecules dependls on the body size of the brachiopod and how long it has been deprived of particulate food, as well as on the conceilitradion and, temperature of the solutions containing the amino acids. However, the realistic net energy gained in this way from sea water proves negligible in comparison with the metabolic consumption observed in unstarved braohiopods. Since it is unlikely that the primary purpose of the epitheliail transport is concerned with nutriltion, dissolved nutrients will not directly influence Ithe distri:bution piatterns of articulate brachiopods.