Community Structure and Biogeochemical Impacts of Microbial Life on Floating Pumice

Abstract

Volcanic eruptions are a widespread force of geological and ecological disturbance and present recurrent opportunities for the study of biological responses to novel habitat formation. However, scientific study of such events is difficult given their short duration and often distant location. Here we report results from opportunistic sampling of unique volcano-generated habitats formed during the 2011 explosive eruption in the Puyehue-Cordón Caulle complex (Chile), when massive amounts of pumice were ejected, creating novel floating substrata that have never before been characterized from a microbiological perspective. DNA sequencing revealed a dynamic community of microbes that came to inhabit the pumice, with a unique composition distinct from that of the lakes' surface waters and with suggestions of ecological convergence across lakes and sampling times. Furthermore, biogeochemical studies of net nutrient fluxes showed that, while the fresh pumice arriving to the lakes was an initial source of phosphorus (P), colonized pumice had high rates of nitrogen (N) and P uptake and was sufficiently abundant to represent a significant lake-wide nutrient sink. These findings highlight the remarkable versatility of microbes in exploiting novel environments and are consistent with a recent proposal of floating pumice as a favorable environment for the initial origins of life on early Earth.

ANCHOR: a 16S rRNA gene amplicon pipeline for microbial analysis of multiple environmental samples

“…The entirely consistent patterns of water‐ or mouse‐associated bacteria in higher abundance in the U.S. laboratory samples can be extended to both the DA eukaryote OTU, Cryptomonadaceae_12 and the OTU identified as Unknown_bacteria_56 (also absent from sleep station samples). Cryptomonadaceae is an algal family containing genera such as Cryptomonas , which inhabit bodies of freshwater(Tranvik et al ., ) and this specific Cryptomonadaceae_12 sequence has indeed been previously identified (100% similarity) in fresh water samples as an uncultured bacterial clone [interestingly from the same experiment identifying Comamonadaceae MG_12 at 100% similarity as an unknown bacteria (Elser et al ., )]. The Unknown_bacteria_56 sequence was most similar to the known species Lactobacillus murinus (98% similarity) and to a large number of unknown NCBI nt/nr hits (uncultured bacteria at 99% identity), which all derived from mouse microbiome samples taken during two independent experiments [studying the vagina of promiscuous mice and the gut of exercising mice on a high fat diet (MacManes, ; Evans et al ., )].…”

“…Polynucleobacter duraquae is also most often found in fresh water samples (and is free-living unlike many host-associated Polynucleobacter species) (Hahn et al, 2016). Similarly, the OTUs annotated as Comamonadaceae MG_12 (placed as within the genera Acidovorax or Limnohabitans) and Bordetella_1 did not correspond to any well characterized bacterial species, but have previously been identified or isolated as unknown bacteria (100% similar) from numerous samples deriving from fresh water (Shaw et al, 2008;Mueller-Spitz et al, 2009;Wu et al, 2012;Elser et al, 2014;Balmonte et al, 2016;Huang et al, 2016) and were also only detected in laboratory samples.…”

Presence of diverse Candidatus Methylomirabilis oxyfera -like bacteria of NC10 phylum in agricultural soils

“…The most closely related sequences of these two groups were the clones recovered from lake sediments (Deutzmann and Schink ) and lake water columns (Elser et al . ), with 95–98% identity. The group B members were found to be dominant in every examined core sample (Fig.…”

Microbial biogeography of 1,000 geothermal springs in New Zealand

“…This research provides a comprehensive dataset that should be used as a foundation for future studies (e.g. diversification 66 and drift 67,68 elucidation on targeted spring taxa). It complements the recently published Earth Microbiome Project 45 by expanding our knowledge of the biogeographical constraints on aquatic ecosystems using standardised quantification of broad physicochemical spectrums.…”