Diversity of the Microeukaryotic Community in Sulfide-Rich Zodletone Spring (Oklahoma)

Abstract

The microeukaryotic community in Zodletone Spring, a predominantly anaerobic sulfide and sulfur-rich spring, was examined using an 18S rRNA gene cloning and sequencing approach. The majority of the 288 clones sequenced from three different locations at Zodletone Spring belonged to the Stramenopiles, Alveolata, and Fungi, with members of the phylum Cercozoa, order Diplomonadida, and family Jakobidae representing a minor fraction of the clone library. No sequences suggesting the presence of novel kingdom level diversity were detected in any of the three libraries. A large fraction of stramenopile clones encountered were monophyletic with either members of the genus Cafeteria (order Bicosoecida) or members of the order Labyrinthulida (slime nets), both of which have so far been encountered mainly in marine habitats. The majority of the observed fungal clone sequences belonged to the ascomycetous yeasts (order Saccharomycetales), were closely related to yeast genera within the Hymenobasidiomycetes (phylum Basidiomycetes), or formed a novel fungal lineage with several previously published or database-deposited clones. To determine whether the unexpected abundance of fungal sequences in Zodletone Spring clone libraries represents a general pattern in anaerobic habitats, we generated three clone libraries from three different anaerobic settings (anaerobic sewage digester, pond sediment, and hydrocarbon-exposed aquifer sediments) and partially sequenced 210 of these clones. Phylogenetic analysis indicated that clone sequences belonging to the kingdom Fungi represent a significant fraction of all three clone libraries, an observation confirmed by phospholipid fatty acid and ergosterol analysis. Overall, this work reveals an unexpected abundance of Fungi in anaerobic habitats, describes a novel, yet-uncultured group of Fungi that appears to be widespread in anaerobic habitats, and indicates that several of the previously considered marine protists could also occur in nonmarine habitats.The utilization of culture-independent approaches for describing microbial assemblages in various ecosystems has altered our view on the breadth of prokaryotic diversity. For example, by extensive 16S rRNA gene-based analysis of various marine and terrestrial ecosystems, the number of bacterial divisions and candidate divisions has increased from 12 in 1987 (68) to at least 52 (53). Similarly, numerous novel archaeal lineages, many of which have a global distribution, have been detected in both marine (11) and terrestrial (7) ecosystems.Recently, a similar approach utilizing small subunit (SSU) rRNA gene amplification, cloning, and sequencing has been applied to study eukaryotic diversity. The few available studies primarily examined the microeukaryotic community in different marine environments, including the photic and aphotic zones of pelagic oceans (12,13,25,39,43,61), anoxic marine salt marsh sediments (60), and hydrothermal vents (17,38). Collectively, these studies suggest an unexpected level of diversity with the detection of sequen...

The Environmental Clade LKM11 and Rozella Form the Deepest Branching Clade of Fungi

“…1). The LKM11 (AJ130849) sequence branched within this group, as well as other environmental sequences classified in other studies as related to it (Lefranc et al 2005;Luo et al 2005;Šlapeta et al 2005;Van Hannen et al 1999). Given the high statistical support in our phylogenetic analyses for the Rozella/LKM11 clade, we propose here to name this group ''Rozellida'', in reference to the genus Rozella.…”

Protistan community patterns within the brine and halocline of deep hypersaline anoxic basins in the eastern Mediterranean Sea

“…some chytridiomycetes) no strictly anaerobic fungi have been described and they have been thought to play only a minor role in ecosystem processes in anaerobic systems (Dighton 2003;Mansfield and Barlocher 1993). This contrasts with molecular diversity surveys in anaerobic aquatic environments, where fungal sequences sometimes account for a significant fraction of the clones (Dawson and Pace 2002;Edgcomb et al 2002;Luo et al 2005;Stoeck and Epstein 2003;Stoeck et al 2006;Stoeck et al 2007). Support for the survival and growth of fungi in anaerobic environments comes from reports of some ascomycetes (Dumitru et al 2004;Sonderegger et al 2004) and some basidiomycetes (Fell et al 2001) that are capable of fermentation and anaerobic growth, some of which have even been isolated from anaerobic deep-sea environments (Nagahama et al 2003).…”

Composition and genetic diversity of picoeukaryotes in subtropical coastal waters as revealed by 454 pyrosequencing

“…For instance, the third most abundant phylotype OTU in the MB sample (uncultured prasinophyte clone PROSOPE.C1-80m.96) was retrieved from the Mediterranean Sea , whereas the third most abundant OTU in the TH sample (uncultured ciliate clone 9_153) was recovered from the anoxic layer of the East Sea sediment in the northwestern Pacific (Park et al, 2008). In addition, stramenopiles, which have been found abundantly in anoxic and extreme environments (Stoeck and Epstein, 2003;Luo et al, 2005), seemed to dominate the TH sample (Figure 1). Because high levels of phytoplankton biomass could lead to hypoxia/ anoxia (Roman et al, 1993), the presence of OTUs with high adaptability to anoxic environments in the eutrophic waters of TH is not unexpected.…”