Spatial and Temporal Patterns in the Microbial Diversity of a Meromictic Soda Lake in Washington State

Abstract

The microbial community diversity and composition of meromictic Soap Lake were studied using culturedependent and culture-independent approaches. The water column and sediments were sampled monthly for a year. Denaturing gradient gel electrophoresis of bacterial and archaeal 16S rRNA genes showed an increase in diversity with depth for both groups. Late-summer samples harbored the highest prokaryotic diversity, and the bacteria exhibited less seasonal variability than the archaea. Most-probable-number assays targeting anaerobic microbial guilds were performed to compare summer and fall samples. In both seasons, the anoxic samples appeared to be dominated by lactate-oxidizing sulfate-reducing prokaryotes. High numbers of lactate-and acetate-oxidizing ironreducing bacteria, as well as fermentative microorganisms, were also found, whereas the numbers of methanogens were low or methanogens were undetectable. The bacterial community composition of summer and fall samples was also assessed by constructing 16S rRNA gene clone libraries. A total of 508 sequences represented an estimated >1,100 unique operational taxonomic units, most of which were from the monimolimnion, and the summer samples were more diverse than the fall samples (Chao1 ‫؍‬ 530 and Chao1 ‫؍‬ 295, respectively). For both seasons, the mixolimnion sequences were dominated by Gammaproteobacteria, and the chemocline and monimolimnion libraries were dominated by members of the low-G؉C-content group, followed by the Cytophaga-Flexibacter-Bacteroides (CFB) group; the mixolimnion sediments contained sequences related to uncultured members of the Chloroflexi and the CFB group. Community overlap and phylogenetic analyses, however, not only demonstrated that there was a high degree of spatial turnover but also suggested that there was a degree of temporal variability due to differences in the members and structures of the communities.

Planktonic bacterial community composition of an extremely shallow soda pond during a phytoplankton bloom revealed by cultivation and molecular cloning

“…2) were consistent with the results of bacterial diversity revealed from the water of four Swedish lakes during cyanobacterial blooms using molecular biological methods (Eiler and Bertilsson, 2004). However, many Böddi-szék clones showed the highest sequence similarities to uncultured environmental clones originating from similar saline and alkaline aquatic environments (Dimitru et al 2008;Humayoun et al 2003;Mesbah et al 2007). In accordance with our results, studying the prokaryotic communities inhabiting the water and sediment of Wadi an Natrun lakes (Egypt), Mesbah et al (2007) also revealed an unexpected phylogenetic diversity and found that none of their rarefaction curves obtained from the analysis of clone libraries reached plateaus.…”

“…Recently, the cultivation dependent and independent analyses of planktonic and sediment microbial communities include, among others, studying the soda lakes of South-East Siberia, Russia (Foti et al 2007(Foti et al , 2008, North-East Mongolia (Sorokin et al 2004), Inner Mongolia, China (Zhang et al 2001;Ma et al 2004a), Lonar Lake, India (Wani et al 2006;Joshi et al 2008), the East African Rift Valley, Kenya and Tanzania (Rees et al 2004;Mwirichia et al 2010Mwirichia et al , 2011, Wadi An Natrun, Egypt (Mesbah et al 2007), as well as Mono Lake, California, USA (Hollibaugh et al 2001;Humayoun et al 2003) and Soap Lake, Washington, USA (Dimitru et al 2008).…”

Vertical Distribution of Functional Potential and Active Microbial Communities in Meromictic Lake Kivu

“…Community Composition at a High Taxonomic Level Due to the strong vertical chemical gradients and zonation of redox reactions with depth, a clear vertical stratification of microbial communities is usually observed for meromictic lakes [48][49][50][51]. In spite of the different extraction protocols used, the relative abundances of potentially active and bulk bacterial and archaeal communities were mostly similar at the phylum level, with some notable exceptions.…”

Complete Genome Sequence of the Haloalkaliphilic, Hydrogen-Producing Bacterium Halanaerobium hydrogeniformans

“…Halanaerobium hydrogeniformans (formerly Halanaerobium sapolanicus) was isolated from haloalkaline (pH ϳ10, 15-to 140-g/liter NaCl), anaerobic sediments of Soap Lake, WA, with extraordinarily high sulfide concentrations of up to 10 g/liter (1,3,8,12). It is an obligately anaerobic, Gram-negative, nonmotile, nonsporulating, elongated rod.…”