Diversity and community structure within anoxic sediment from marine salinity meromictic lakes and a coastal meromictic marine basin, Vestfold Hills, Eastern Antarctica

Abstract

16S rDNA clone library analysis was used to examine the biodiversity and community structure within anoxic sediments of several marine-type salinity meromictic lakes and a coastal marine basin located in the Vestfolds Hills area of Eastern Antarctica. From 69 to 130 (555 total) 16S rDNA clones were analysed from each sediment sample, and restriction fragment length polymorphism (RFLP) and sequence analysis grouped the clones into 202 distinct phylotypes (a clone group with sequence similarity of >0.98). A number of phylotypes and phylotype groups predominated in all libraries, with a group of 10 phylotypes (31% of clones) forming a novel deep branch within the low G+C Gram-positive division. Other abundant phylotypes detected in several different clone libraries grouped with Prochlorococcus cyanobacteria, diatom chloroplasts, delta proteobacteria (Desulfosarcina group, Syntrophus and Geobacterl Pelobacter/Desulphuromonas group), order Chlamydiales (Parachlamydiaceae) and Spirochaetales (wall-less Antarctic spirochaetes). Most archaeal clones detected (3.1% of clones) belonged to a highly diverged group of Euryarchaeota clustering with clones previously detected in rice soil, aquifer sediments and hydrothermal vent material. Little similarity existed between the phylotypes detected in this study and other clone libraries based on marine sediment, suggesting that an enormous prokaryotic diversity occurs within marine and marine-derived sediments.

High 16S rDNA bacterial diversity in glacial meltwater lake sediment, Bratina Island, Antarctica

“…Our results show that the prokaryotic diversity is comparable to, if not higher than, that shown in other studies of Antarctic meltwater lake sediments (Bowman et al 2000), microbial mats in East Antarctic lakes (Brambilla et al 2001), and the Arctic Ocean (Raven-schlag et al 1999), each of which report a high level of complexity in the prokaryotic community structure. The linearity of the rarefaction curve (Fig.…”

Root colonization by Pseudomonas putida: love at first sight

“…Our data and those of Bowman et al (3) indicated that new distinct chlamydial lineages exist in natural environments as different as Antarctic marine salinity lake sediments and European freshwater ponds. All the chlamydiae described until now are able to infect vertebrates and to induce diseases : it may be of interest to estimate their prevalence and diversity in various natural habitats and in this way to identify possible sources of infections for both known and new chlamydiae.…”

“…Inoculation and determination of the number of cells associated with the seeds\roots was done as described (3,4). Results are the average of two assays where each data point corresponds to duplicate samples from three seedlings.…”

“…1e], and sown in pots containing vermiculite. At different times, plants were removed and the number of bacteria associated with the root was determined by plating on selective medium as described (3,4). Around 1 % of the inoculated bacteria attached to the seedlings after 1 h incubation in minimal medium.…”

Ace Lake: three decades of research on a meromictic, Antarctic lake

“…A molecular study using 16S rRNA gene clone library analysis examined the community structure of the anoxic sediments (Bowman et al 2000). Diversity in the sulphide-rich anoxic sediments was surprisingly high.…”