Major and comparable roles for free-living and attached bacteria in the degradation of Phaeocystis-derived organic matter in Belgian coastal waters of the North Sea

Abstract

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 14:39-48 (1998) - doi:10.3354/ame014039 Major and comparable roles for free-living and attached bacteria in the degradation of Phaeocystis-derived organic matter in Belgian coastal waters of the North Sea S. Becquevort*, V. Rousseau, C. Lancelot Groupe de Microbiologie des Milieux Aquatiques, Université Libre de Bruxelles, Campus de la Plaine, CP 221, Boulevard du Triomphe, B-1050 Brussels, Belgium *E-mail: sbecq@pop.ulb.ac.be Microbial degradation of Phaeocystisglobosa colonies and their derived organic matter by free-living and attached bacteria was investigated in Belgian coastal waters during the spring development of diatom-Phaeocystis colonies in 1994. Results obtained show concomitant evolution of hydrolytic ectoprotease and b-ectoglucosidase ectoenzymatic activities with respect to the phytoplankton bloom, suggesting that the low biodegradability of Phaeocystis colonies leading to transient accumulations of Phaeocystis-derived material in the coastal North Sea was not due to a lag phase required for the induction of b-ectoglucosidase. Up to 66% of total bacterial biomass was found attached to particles larger than 10 μm. While occurring always in low abundance compared to free-living bacteria, both the average specific biomass and growth rate of particle-attached bacteria were very high, i.e. 60 fg C cell-1 and 0.28 h-1, respectively. Similarly, specific ectoenzymatic activities of particle-attached bacteria were on average about 5 times higher than those characterising free-living bacteria. Budget calculations show a 53% contribution of Phaeocystis-attached bacteria to the mineralisation of Phaeocystis-associated production, i.e. a 53:47% role for attached and free-living bacteria, respectively. Phaeocystis degradation · Free-living and particle-attached bacteria · Ectoenzymatic activity · Growth rate Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 14, No. 1. Publication date: January 02, 1998 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 1998 Inter-Research.