Experiments to determine the relevance of dissolved amino acids for the nutrition of marine benthic animals

In vitro and in situ several macrobenthic species were found to show highest uptake rates of amino acids at low temperatures of 0°-10° C. The rates decreased at a higher temperature of 15° C which favoured the activity and the development of microorganisms. However, the significance of competitive microorganisms was less striking in the in situ experiments than under laboratory conditions. Phenylalanine was most readily taken up although "aufwuchs" of Fucus serratus and Gammarus sp. was found to show primary uptake of aspartic acid. Arthropods were also able to take up dissolved amino acids but in much lower quantities than molluscs and polychaetes. Dissolved amino acids in the water column hardly penetrated the sediment if this was covered by a layer of detritus