Molecular analysis of microbial communities in mobile deltaic muds of Southeastern Papua New Guinea

A culture-independent examination of microbial diversity in mobile deltaic sediments from the Gulf of Papua, Papua New Guinea, was conducted by sequen ce analysis of 16S rDNA clone library. Universal small subunit primers were used to amplify DNA extracted from the sediment. Of 91 clones randomly sel ected from the library, 33 contained unique non-chimeric sequences. Analysi s of these unique sequences showed that the majority of them belonged to ba cteria (94.5%), with proteobacteria being the dominant division (74.8%). On e sequence belonging to Crenarchaeota and another to Euryarchaeota were fou nd as well. Bacterial sequences belonging to the following major divisions were identified: Cytophaga-Flexibacter-Bacteroides (5.5%), low CC Gram-posi tives (1.1%), Nitrospira group (3.3%), OP8 candidate division (2.2%),OS-K c andidate division (2.2%), Planctomyces (1.1%), alpha, delta, gamma and epsi lon-subdivisions of Proteobacteria (4.4, 20.9, 19.8 and 23.1%, respectively ) and Spirochaetales (4.4%). The composition of 16S rDNA library of the Gul f of Papua sediments is similar to those for deepwater sediments from aroun d the Japanese Islands, indicating a possible cosmopolitan nature of microb ial communities in suboxic and anoxic sediments of the Pacific. It appears that many Papua/New Guinea sequences are loosely affiliated with bacteria i nvolved in sulfur cycling, thus supporting the hypothesis that the sulfur c ycle may be important in early diagenesis of suboxic sediments. (C) 2000 Fe deration of European Microbiological Societies. Published by Elsevier Scien ce B.V. All rights reserved.