Bacterial succession during biodegradation of the kelp Alaria esculenta (L.) Greville

Abstract

In northern latitudes large quantities of kelp can be dislodged by ice scouring during spring and early summer. Quantities of kelp are then available to enter the detrital food chain. Bacterial succession, on decaying fronds of the brown macroalga Alaria esculenta, was investigated. There was a loss of approximately 70% of the algal mass during late spring and summer. During this time Vibrio dominated the heterotrophic bacterial population. Species of marine Pseudomonas comprised about 10–30% of the population, depending upon the occasion of isolation. By using numerical taxonomy it was shown that the strains of Vibrio formed distinct and separate clusters according to the occasion on which they were isolated. Among Pseudomonas strains a more gradual change was observed, but by the time of the final isolation, the Pseudomonas strains were different from those isolated at the beginning of the study. The results of characterization tests showed that strains from all clusters were suited to growth on substrates which are components of brown algae and that a succession of bacterial species, of more than one genus and family, occurred during the decay process.