• Home
  • Search Results
  • Diversity of freshwater Epsilonproteobacteria and dark inorganic carbon fixation in the sulphidic redoxcline of a meromictic karstic lake.

Diversity of freshwater Epsilonproteobacteria and dark inorganic carbon fixation in the sulphidic redoxcline of a meromictic karstic lake.

FEMS microbiology ecology (2015-07-22)
Imma Noguerola, Antonio Picazo, Marc Llirós, Antonio Camacho, Carles M Borrego
ABSTRACT

Sulfidic redoxclines are a suitable niche for the growth and activity of different chemo- and photolithotrophic sulphide-oxidizing microbial groups such as the Epsilonproteobacteria and the green sulfur bacteria (GSB). We have investigated the diversity, abundance and contribution to inorganic carbon uptake of Epsilonproteobacteria in a meromictic basin of Lake Banyoles. CARD-FISH counts revealed that Epsilonproteobacteria were prevalent at the redoxcline in winter (maximum abundance of 2 × 10(6) cells mL(-1), ≈60% of total cells) but they were nearly absent in summer, when GSB bloomed. This seasonal trend was supported by 16S rRNA gene pyrotag datasets, which revealed that the epsilonproteobacterial community was mainly composed of a member of the genus Arcobacter. In situ incubations using NaH(14)CO3 and MAR-CARD-FISH observations showed that this population assimilated CO2 in the dark, likely being mainly responsible for the autotrophic activity at the redoxcline in winter. Clone libraries targeting the aclB gene provided additional evidence of the potential capacity of these epsilonproteobacteria to fix carbon via rTCA cycle. Our data reinforce the key role of Epsilonproteobacteria in linking carbon and sulphur cycles, extend their influence to freshwater karstic lakes and raise questions about the actual contribution of chemolithotrophy at their redoxcline and euxinic water compartments.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Magnesium chloride, BioReagent, suitable for insect cell culture, ≥97.0%
Sigma-Aldrich
Magnesium chloride, powder, <200 μm
Sigma-Aldrich
Magnesium chloride, AnhydroBeads, −10 mesh, 99.9% trace metals basis
Sigma-Aldrich
Magnesium chloride, AnhydroBeads, −10 mesh, 99.99% trace metals basis
Sigma-Aldrich
Magnesium chloride, anhydrous, ≥98%
Sigma-Aldrich
Magnesium chloride solution, BioUltra, for molecular biology, ~0.025 M in H2O
Sigma-Aldrich
Magnesium chloride solution, 0.1 M
Sigma-Aldrich
Magnesium chloride solution, BioUltra, for molecular biology, ~1 M in H2O
Sigma-Aldrich
Magnesium chloride solution, BioUltra, for molecular biology, 2 M in H2O
Sigma-Aldrich
Magnesium chloride solution, PCR Reagent, 25 mM MgCI2 solution for PCR
Sigma-Aldrich
Magnesium chloride solution, for molecular biology, 1.00 M±0.01 M