Dominance of oligotrophic bacteria in surface waters above Gunnerus and Astrid Ridge, Antarctic Ocean


Contact
ttan [ at ] awi-bremerhaven.de

Abstract

From enrichment cultures in dialysis chambers held in natural seawater tanks, 104 strains were isolated and kept in culture. All strains proved to be Gram-negative and psychrotrophic, having optimum growth temperatures of between 20 and 24 °C. Maximal growth temperatures were 30 to 37 °C, or even higher. With 55 isolates, substrate utilizations in Biolog MicroPlates were determined, and the obtained metabolic fingerprints used for clustering. Five groups could be distinguished at the 80% similarity level. Fifteen strains belonged to cluster 1, seven strains to cluster 2, and each of the clusters 3 and 4 contained nine strains. Cluster 5 can be divided into subcluster 5a and 5b, with 6 strains showing a few substrates metabolized, and 9 strains without any reactions, or weak reactions for one or two substrates, respectively. Each cluster could be characterized by specific metabolic fingerprints. Strains from cluster 1 metabolized N-acetyl-D-glucosamine, alpha-hydroxybutyric acid and gamma-hydroxybutyric acid, strains from cluster 2 citric acid, formic acid, thymidine and putrescine, strains from cluster 3 glycyl-L-aspartic acid, glycyl-L-glutamic acid, L-threonine and inosine, whereas strains from cluster 4 metabolized alpha-cyclodextrin and N-acetyl-D-galactosamine, typically. Methylamine was not utilized by the isolates, but strains from cluster 1, 2 and 3 could grow on basal seawater agar. Morphological characteristics and photomicrographs of the oligotrophic strains are presented. Due to their typical morphologies and ampicillin resistence, the nine strains from cluster 3 can be regarded as new species of the genus Planctomyces. These bacteria have not been cultivated before.



Item Type
Article
Authors
Divisions
Programs
Publication Status
Published
Eprint ID
3068
Cite as
Tan, T. L. , Joiris, C. R. , Glansdorff, N. and Rüger, H. J. (1999): Dominance of oligotrophic bacteria in surface waters above Gunnerus and Astrid Ridge, Antarctic Ocean , Archiv für Hydrobiologie, Special Issues Advances in Limnology, 54 , pp. 237-253 .


Share
Add to AnyAdd to TwitterAdd to FacebookAdd to LinkedinAdd to PinterestAdd to Email

Research Platforms

Campaigns
ANT > VIII > 6


Actions
Edit Item Edit Item