title: Archaea in the Gulf of Aqaba.
abstract: Using a polyphasic approach, we examined the presence of Archaea in the Gulf of Aqaba, a warm marine ecosystem, isolated from major ocean currents and subject to pronounced seasonal changes in hydrography. Catalyzed reported deposition FISH analyses showed that Archaea make up to >20% of the prokaryotic community in the Gulf. A spatial separation between the two major phyla of Archaea was observed during summer stratification. Euryarchaeota were found exclusively in the upper 200 m, whereas Crenarchaeota were present in greater numbers in layers below the summer thermocline. 16S rRNA gene-based denaturing gradient gel electrophoresis confirmed this depth partitioning and revealed further diversity of Crenarchaeota and Euryarchaeota populations along depth profiles. Phylogenetic analysis showed pelagic Crenarchaeota and Euryarchaeota to differ from coral-associated Archaea from the Gulf, forming distinct clusters within the Marine Archaea Groups I and II. Endsequencing of fosmid libraries of environmental DNA provided a tentative identification of some members of the archaeal community and their role in the microbial community of the Gulf. Incorporation studies of radiolabeled leucine and bicarbonate in the presence of different inhibitors suggest that the archaeal community participates in autotrophic CO(2) uptake and contributes little to the heterotrophic activity.
authors: Department of Plant and Environmental Sciences, The Institute of Life Sciences, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel. danny.ionescu@mail.huji.ac.il
authors: Danny
authors: D
authors: Ionescu
authors: Sigrid
authors: S
authors: Penno
authors: Maya
authors: M
authors: Haimovich
authors: Branko
authors: B
authors: Rihtman
authors: Aram
authors: A
authors: Goodwin
authors: Daniel
authors: D
authors: Schwartz
authors: Lena
authors: L
authors: Hazanov
authors: Mark
authors: M
authors: Chernihovsky
authors: Anton F
authors: AF
authors: Post
authors: Aharon
authors: A
authors: Oren
mesh_terms: D019615:Crenarchaeota / Q000145:classification / Q000235:genetics*; D019641:DNA, Archaeal / Q000235:genetics; D019605:Euryarchaeota / Q000145:classification / Q000235:genetics*; D020459:Genes, rRNA; D017404:In Situ Hybridization, Fluorescence; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012623:Seawater / Q000382:microbiology; D017422:Sequence Analysis, DNA; D014871:Water Microbiology
chemical_list: D019641:DNA, Archaeal; D012336:RNA, Ribosomal, 16S