UPTAKE OF NATURALLY OCCURRING PRIMARY AMINES BY MARINE ANNELIDS

Abstract

1. The interstitial water of inshore sediments on the Danish coast contains rather high concentrations of primary amines. The average concentration observed was 50 micromoles per liter expressed as equivalent glycine concentration.2. The concentration of primary amines decreased in deeper layers of the sediment.3. Naturally occurring primary amines from interstitial water are taken up rapidly by Nereis diversicolor and Capitella capitata. The rate of net influx is of the same order of magnitude as the total requirement for reduced carbon provided primary amines are interpretedas principally consisting of free amino acids.4. Net influx of known amino acids was also examined. Capitella takes up glycine, serine, glutamate and aspartate at rates comparable to those observed for naturally occurring amines in the interstitial water. Nereis takes up glycine and serine at comparable rates but obtains glutamate and aspartate from solution very slowly if at all.5. Subsurface irrigation of sediment samples with aerated sea water increases the concentration of primary amines in the interstital water of deeper sediment layers. The same effect results when Nereis constructs and irrigates a burrow.6. These observations support the hypothesis that a large net transepidermal influx of small organic compounds occurs in members of the annelid infauna. Furthermore, this ability to obtain and utilize primary amines from solution is associated with behavior which results in generating additonal primary amines.7. It is suggested that the construction of burrows and their irrigation by the infauna serves to increase the surface area of the transition zone between aerobic and anaerobic conditions by extending it into deeper sediment layers. The observed increase in primary amines may be related to the intense microbial activity which characterizes this transition zone.