Planctomycetes as a Vital Constituent of the Microbial Communities Inhabiting Different Layers of the Meromictic Lake Sælenvannet (Norway)

Abstract

Meromictic lakes are permanently stratified lakes that display steep gradients in salinity, oxygen and sulphur compounds tightly linked to bacterial community structure and diversity. Lake Sælenvannet is a meromictic lake located south of Bergen, Norway. The 26 m deep lake is connected to the open sea and permanently stratified into two layers separated by a chemocline. The upper water layer is brackish with major input from water runoff from the surroundings. The bottom layer consists of old saline water with low or no oxygen concentrations. Bacteria from phylum Planctomycetes are reported to be ubiquitous in lake environments. They are involved in the degradation of complex carbon sources in aquatic environments and are also linked to anaerobic processes such as fermentation and sulphur reduction. To study Planctomycete distribution along a chemical gradient, we sampled the water column throughout Lake Sælenvannet in 2012 and profiled the microbial community using 16S rRNA amplicon sequencing (metabarcoding) with 454 pyrosequencing. Planctomycete-related 16S rRNA gene sequences were found to be present both in the oxic and anoxic parts of the lake and showed an uneven distribution throughout the water column, with the highest relative abundance of 10% found in the saline anoxic layer at 15 m depth. In a follow-up study in 2014, samples from eight different depths were collected for enrichment and isolation of novel Planctomycetes. This study resulted in successful isolation in pure culture of 10 isolates affiliated to four different genera from the family Planctomycetaceae. One strain closely related to Blastopirellula cremea was isolated from 9 m depth, and two novel strains affiliated to the genera Stieleria and Gimesia were isolated at 7 and 9 m depths, respectively. Furthermore, seven isolates with identical 16S rRNA gene sequences were retrieved from seven different depths which varied greatly in salinity and chemical composition. These isolates likely represent a new species affiliated to Rubinisphaera. The adaptation of this novel Planctomycete to water depths spanning the entire chemical gradient could indicate a high phenotypic plasticity and/or a very efficient survival strategy. Overall, our results show the presence of a diverse group of Planctomycetes in Lake Sælenvannet, with a strong potential for novel adaptations to chemical stress factors.

Local Habitat Filtering Shapes Microbial Community Structure in Four Closely Spaced Lakes in the High Arctic

“…Planctomycetes were present in all four Stuckberry Lakes (Figure 3), as expected given the wide freshwater distribution of this group (Zwart et al, 2002;Newton et al, 2011). These heterotrophs have various important ecosystem functions, including contributing to the degradation of complex organic compounds (Schlesner et al, 2004;Fuchsman et al, 2012), and they are mostly found in the hypolimnia of deep oxygenated lakes (Okazaki and Nakano, 2016;Karlov et al, 2017;Okazaki et al, 2017;Storesund et al, 2020). By contrast, 2FB Lake, where Planctomycetes reached their greatest relative abundances in our dataset (40%) (Figure 3C), was shallow and hypoxic.…”

Microbiome Diversity Analysis of the Bacterial Community in Idah River, Kogi State, Nigeria

“…However, the role Geothrix plays in reducing metal ions makes the bacteria environmentally essential. Planctomycetes are ubiquitous in both aquatic and soil ecosystems, and they are mostly chemoorganotrophic microorganisms that break down complex organic compounds [38]. In the river, this phylum contained Pirellula, Blastopirellula, Candidatus Annammoximicrobium moscowii, which was discovered as a novel microorganism involved with anaerobic ammonium oxidation for treatment of filtrate of wastewater fermented residue [39].…”

Planctomycetes as Host-Associated Bacteria: A Perspective That Holds Promise for Their Future Isolations, by Mimicking Their Native Environmental Niches in Clinical Microbiology Laboratories

“…The first report of the isolation of a planctomycete in axenic cultures is due to the work of James T. Staley (Staley, 1973). During the last decade, several members of Planctomycetes were isolated in pure culture and described as representing new genera, namely Schlesneria (Kulichevskaya et al, 2007b), Singulisphaera (Kulichevskaya et al, 2008;Kulichevskaya et al, 2012a), Zavarzinella (Kulichevskaya et al, 2009), Aquisphaera (Bondoso et al, 2011), Telmatocola (Kulichevskaya et al, 2012b), Paludisphaera (Kulichevskaya et al, 2016;Kaushik et al, 2020), Roseimaritima (Bondoso et al, 2015;Kumar et al, 2020b), Rubripirellula (Bondoso et al, 2015;Kallscheuer et al, 2019b), Fimbriiglobus (Kulichevskaya et al, 2017a), Tundrisphaera (Kulichevskaya et al, 2017b), Mariniblastus (Lage et al, 2017), Caulifigura (Kallscheuer et al, 2020a), Tuwongella (Seeger et al, 2017), Crateriforma (Peeters et al, 2020c), Fuerstia (Kohn et al, 2016;Kohn et al, 2019), Novipirellula (Kallscheuer et al, 2019c), Tautonia (Kovaleva et al, 2019;Jogler et al, 2020) Limnoglobus (Kulichevskaya et al, 2020b), Thalassoglobus (Kohn et al, 2020a;Rivas-Marin et al, 2020c), Symmachiella (Salbreiter et al, 2020), Gimesia (Scheuner et al, 2014;Kumar et al, 2020a;Wang et al, 2020), Stieleria (Sandargo et al, 2020;Storesund et al, 2020;Surup et al, 2020), Aureliella (Kallscheuer et al, 2020b), Maioricimonas (Rivas-Marin et al, 20...…”