Format

Send to

Choose Destination
Appl Environ Microbiol. 2013 Jul;79(14):4272-81. doi: 10.1128/AEM.00467-13. Epub 2013 May 3.

Insights into the structure and metabolic function of microbes that shape pelagic iron-rich aggregates ("iron snow").

Author information

1
Institute of Ecology, Friedrich Schiller University Jena, Jena, Germany.

Abstract

Microbial ferrous iron [Fe(II)] oxidation leads to the formation of iron-rich macroscopic aggregates ("iron snow") at the redoxcline in a stratified lignite mine lake in east-central Germany. We aimed to identify the abundant Fe-oxidizing and Fe-reducing microorganisms likely to be involved in the formation and transformation of iron snow present in the redoxcline in two basins of the lake that differ in their pH values. Nucleic acid- and lipid-stained microbial cells of various morphologies detected by confocal laser scanning microscopy were homogeneously distributed in all iron snow samples. The dominant iron mineral appeared to be schwertmannite, with shorter needles in the northern than in the central basin samples. Total bacterial 16S rRNA gene copies ranged from 5.0 × 10(8) copies g (dry weight)(-1) in the acidic central lake basin (pH 3.3) to 4.0 × 10(10) copies g (dry weight)(-1) in the less acidic (pH 5.9) northern basin. Total RNA-based quantitative PCR assigned up to 61% of metabolically active microbial communities to Fe-oxidizing- and Fe-reducing-related bacteria, indicating that iron metabolism was an important metabolic strategy. Molecular identification of abundant groups suggested that iron snow surfaces were formed by chemoautotrophic iron oxidizers, such as Acidimicrobium, Ferrovum, Acidithiobacillus, Thiobacillus, and Chlorobium, in the redoxcline and were rapidly colonized by heterotrophic iron reducers, such as Acidiphilium, Albidiferax-like, and Geobacter-like groups. Metaproteomics yielded 283 different proteins from northern basin iron snow samples, and protein identification provided a glimpse into some of their in situ metabolic processes, such as primary production (CO2 fixation), respiration, motility, and survival strategies.

PMID:
23645202
PMCID:
PMC3697501
DOI:
10.1128/AEM.00467-13
[Indexed for MEDLINE]
Free PMC Article

Publication type, MeSH terms, Substances, Secondary source ID

Publication type

MeSH terms

Substances

Secondary source ID

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center