PMC

Porewater Mn²⁺ concentrations during incubations of GF and UB sediments. Mn²⁺ concentrations in all three S incubations stayed <5 μℳ.

Acetate concentrations during incubations of the GF and UB sediments. Acetate concentrations during the S sediment incubations were not measured.

DIC concentration corrected for CaCO₃ precipitation during incubations of Gullmar Fjord (GF), Ulleung Basin (UB) and Skagerrak (S) sediments.

T-RFLP analysis (XapI) of 16S rRNA-complimentary DNA amplicons obtained from one selected heavy and light RNA fraction of incubations with ¹³C-acetate of GF, UB and S sediments in comparison with the original sediment at day 0. Representing 16S rRNA-complimentary DNA clones of major T-RFs can be found in and a differential T-RFLP analysis (MspI) of heavy and light fractions in . Numbers in parentheses represent the density of fractions in g ml⁻¹, heavy fractions (⩾1.80 mg l⁻¹) are marked by gray background.

16S rRNA consensus tree showing the affiliation of OTUs detected in heavy SIP fractions of ¹³C-actetate incubations of GF, UB and S sediments and in acetate-oxidizing manganese-reducing MPN cultures of GF sediment (GF-MPN). Sequences of Pelobacter sp. A3Mn2, Arcobacter sp. B4Mn1 and Shewanella strain D1Mn were clone sequences of manganese-reducing MPN counts of Black Sea sediment taken from . Arcobacter-ℒ and Arcobacter ED1 sequences stem from acetate-fed microbial fuel cells of . Stars indicate OTUs for which ¹³C-label incorporation was confirmed by comparative T-RFLP analysis of light and heavy SIP fractions (, ). OTUs that were represented by only one clone sequence are not shown. Relative abundance of OTUs is indicated in . Filled and open circles indicate lineages with >90% and 75–90% maximum likelihood bootstrap support, respectively. Aquifex pyrophilus (M83548) was used as outgroup. The scale bar indicates 5% estimated sequence divergence.