Fig 1.
Geographic locations of two deep sea brine pools in the Red Sea.
The sediment cores from Atlantis II (ABS) and Discovery (DBS) were sectioned for microbial studies. A barite crust was identified between 152 cm and 169 cm by mineral analysis on the ABS. The core of 268 KS was sampled in 1982 by Thisse et al. [19]. The barite crust in the Atlantis II Deep was discovered by Sval'nov et al. (1984) [10].
Fig 2.
Mineral components of a sediment core from the Atlantis II Deep of the Red Sea.
The core (A) was obtained from the Atlantis II Deep (see Fig 1). The layers of interests were selected based on naked eye observation (B). XRD analysis shows that the major components were anhydrite, halite and sphalerite (C). The abundance and distribution of the other minor components FeS2, CaCO3, BaSO4 and SiO2 were indicated by + (<10%), ++ (10%-30%) and +++ (>30%), with halite content discounted (C). Minor components that could not be detected were labeled as 'n.d.'.
Table 1.
Porosity and carbon sources in the ABS sediment layers.
Table 2.
Pyrosequencing results of 16S rDNA amplicons.
Fig 3.
Microbial communities in two sediment cores from the central Red Sea.
Minor groups were referred to the phyla accounted for<2% of all the communities. The compositions of the communities at phylum (A) and order (B) levels were based on sorting of the pyrosequenced 16S rRNA amplicons in SILVA database using confidence level of 80%. The sample IDs were referred to Table 2.
Fig 4.
Phylogenetic trees of 16S rRNA gene sequences of archaeal groups DHVEG1 (A) and Thaumarchaeota group C3 (B) with their closest relatives.
Three representative reads of the most abundant OTUs for deep-sea hydrothermal vent euryarchaeotic group 1 (OTU-RS-DHVEG1) and two for Thaumarchaeota group C3 (OTU-RS-C3) were used to identify their closest relatives in the GenBank. The phylogenetic trees were constructed using Maximum-Likelihood method.