Communities of Archaea and Bacteria in a Subsurface Radioactive Thermal Spring in the Austrian Central Alps, and Evidence of Ammonia-Oxidizing Crenarchaeota

Abstract

Scanning electron microscopy revealed great morphological diversity in biofilms from several largely unexplored subterranean thermal Alpine springs, which contain radium 226 and radon 222. A culture-independent molecular analysis of microbial communities on rocks and in the water of one spring, the "Franz-Josef-Quelle" in Bad Gastein, Austria, was performed. Four hundred fifteen clones were analyzed. One hundred thirty-two sequences were affiliated with 14 bacterial operational taxonomic units (OTUs) and 283 with four archaeal OTUs. Rarefaction analysis indicated a high diversity of bacterial sequences, while archaeal sequences were less diverse. The majority of the cloned archaeal 16S rRNA gene sequences belonged to the soil-freshwatersubsurface (1.1b) crenarchaeotic group; other representatives belonged to the freshwater-wastewater-soil (1.3b) group, except one clone, which was related to a group of uncultivated Euryarchaeota. These findings support recent reports that Crenarchaeota are not restricted to high-temperature environments. Most of the bacterial sequences were related to the Proteobacteria (␣, ␤, ␥, and ␦), Bacteroidetes, and Planctomycetes. One OTU was allied with Nitrospina sp. (␦-Proteobacteria) and three others grouped with Nitrospira. Statistical analyses suggested high diversity based on 16S rRNA gene analyses; the rarefaction plot of archaeal clones showed a plateau. Since Crenarchaeota have been implicated recently in the nitrogen cycle, the spring environment was probed for the presence of the ammonia monooxygenase subunit A (amoA) gene. Sequences were obtained which were related to crenarchaeotic amoA genes from marine and soil habitats. The data suggested that nitrification processes are occurring in the subterranean environment and that ammonia may possibly be an energy source for the resident communities.

A moderately thermophilic ammonia-oxidizing crenarchaeote from a hot spring

“…As only one archaeal 16S rRNA phylotype (by using a threshold of 97% sequence similarity) was found in the enrichment, the retrieved archaeal amoA and amoB gene fragments most likely also originated from this phylotype. In contrast to previous studies, which only reported the presence of AOA-related 16S rRNA or crenarchaeotal amoA gene fragments in thermophilic environments (19,20,(31)(32)(33), we specifically identified the respective organism by CARD-FISH with 16S rRNA-targeted probes as cocci in irregularly shaped aggregates. Furthermore, we propose three independent lines of evidence that, taken together, strongly suggest that the detected archaeon is actually an AOA.…”

“…All 46 sequences were related at Ͼ99.1% similarity to each other and assigned to a monophyletic cluster within Crenarchaeota group I.1b (soil group; Fig. 1) that also included partial 16S rRNA gene sequences recently retrieved from a subsurface radioactive thermal spring (20) and a Wisconsin soil (28). In addition, crenarchaeotal amo genes were PCR-amplified from the enrichment, and 19 and 7 clones were sequenced for amoA and amoB, respectively.…”

“…Since then, AOA were found to outnumber ammonia-oxidizing bacteria (AOB) in several terrestrial and marine systems, including different soils (6), the North Sea and Atlantic Ocean (7), the Pacific Ocean (8), and the Black Sea (9). Furthermore, molecular analyses demonstrated that AOA also occur in association with marine sponges (10)(11)(12)(13), and amoA sequences related to recognized AOA were retrieved in numerous studies from a wide variety of other habitats (7-9, 14-18), including two moderately thermophilic sites with a temperature below 50°C (19,20). The latter findings raise the question of whether ammonia oxidation takes place at elevated temperatures and in particular whether AOA thrive under these conditions.…”

Evidence of global-scale aeolian dispersal and endemism in isolated geothermal microbial communities of Antarctica

“…The study showed that the fumaroles themselves are likely dominated by endemic taxa, including deep-branching Planctomycetes, Acidobacteria and Chloroflexi, as well as many novel, potentially division-level lineages with no known relatives 17 . The few Archaea observed at Tramway Ridge were all classified as Crenarchaeota and were most similar to environmental clones from subsurface environments in South Africa 19 and central Europe 20 .…”

Filogenia molecular e cultivo de Archaea de solos de Cerrado sensu strictoc

“…Desde a sua descoberta, muitos trabalhos vêm relatando a presença de AOAs em diversos ambientes, como solos (Ying et al, 2010;Gubry-Rangin et al, 2011;Zhang et al, 2010), água marinha (Könneke et al, 2005;Wuchter et al, 2006), sedimentos marinhos (Francis et al, 2005;Beman & Francis, 2006), aquários e fontes de água doce (Sauder et al, 2011;Peng et al, 2013), biorreatores de tratamento de esgoto (Park et al, 2006), fontes termais (Weidler et al, 2007), entre outros. Além disso, a predominância de AOAs em relação às AOBs em certos ambientes também vem sendo sugerida, principalmente em alguns solos (Leininger et al, 2006;Nicol et al, 2008).…”