Microbial processes of the carbon and sulfur cycles in an ice-covered, iron-rich meromictic lake Svetloe (Arkhangelsk region, Russia)

Environ Microbiol. 2017 Feb;19(2):659-672. doi: 10.1111/1462-2920.13591. Epub 2016 Dec 8.


Biogeochemical, isotope geochemical and microbiological investigation of Lake Svetloe (White Sea basin), a meromictic freshwater was carried out in April 2014, when ice thickness was ∼0.5 m, and the ice-covered water column contained oxygen to 23 m depth. Below, the anoxic water column contained ferrous iron (up to 240 μμM), manganese (60 μM), sulfide (up to 2 μM) and dissolved methane (960 μM). The highest abundance of microbial cells revealed by epifluorescence microscopy was found in the chemocline (redox zone) at 23-24.5 m. Oxygenic photosynthesis exhibited two peaks: the major one (0.43 μmol C L-1 day-1 ) below the ice and the minor one in the chemocline zone, where cyanobacteria related to Synechococcus rubescens were detected. The maximum of anoxygenic photosynthesis (0.69 μmol C L-1 day-1 ) at the oxic/anoxic interface, for which green sulfur bacteria Chlorobium phaeoclathratiforme were probably responsible, exceeded the value for oxygenic photosynthesis. Bacterial sulfate reduction peaked (1.5 μmol S L-1 day-1 ) below the chemocline zone. The rates of methane oxidation were as high as 1.8 μmol CH4 L-1 day-1 at the oxi/anoxic interface and much lower in the oxic zone. Small phycoerythrin-containing Synechococcus-related cyanobacteria were probably involved in accumulation of metal oxides in the redox zone.

MeSH terms

  • Carbon / metabolism*
  • Carbon Cycle*
  • Carbon Dioxide / analysis
  • Chlorobi / metabolism
  • Ecosystem
  • Ice Cover*
  • Iron / chemistry*
  • Lakes / chemistry
  • Lakes / microbiology*
  • Methane / analysis
  • Oxidation-Reduction
  • Oxygen
  • Photosynthesis
  • Russia
  • Sulfides
  • Sulfur / metabolism*
  • Water Microbiology


  • Sulfides
  • Carbon Dioxide
  • Sulfur
  • Carbon
  • Iron
  • Methane
  • Oxygen