Limits...
A 'rare biosphere' microorganism contributes to sulfate reduction in a peatland.

Pester M, Bittner N, Deevong P, Wagner M, Loy A - ISME J (2010)

Bottom Line: Methane emission from peatlands contributes substantially to global warming but is significantly reduced by sulfate reduction, which is fuelled by globally increasing aerial sulfur pollution.For the identified Desulfosporosinus species a high cell-specific sulfate reduction rate of up to 341 fmol SO₄²⁻ cell⁻¹ day⁻¹ was estimated.Thus, the small Desulfosporosinus population has the potential to reduce sulfate in situ at a rate of 4.0-36.8 nmol (g soil w. wt.)⁻¹ day⁻¹, sufficient to account for a considerable part of sulfate reduction in the peat soil.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbial Ecology, University of Vienna, Wien, Austria.

ABSTRACT
Methane emission from peatlands contributes substantially to global warming but is significantly reduced by sulfate reduction, which is fuelled by globally increasing aerial sulfur pollution. However, the biology behind sulfate reduction in terrestrial ecosystems is not well understood and the key players for this process as well as their abundance remained unidentified. Comparative 16S rRNA gene stable isotope probing (SIP) in the presence and absence of sulfate indicated that a Desulfosporosinus species, which constitutes only 0.006% of the total microbial community 16S rRNA genes, is an important sulfate reducer in a long-term experimental peatland field site. Parallel SIP using dsrAB (encoding subunit A and B of the dissimilatory (bi)sulfite reductase) identified no additional sulfate reducers under the conditions tested. For the identified Desulfosporosinus species a high cell-specific sulfate reduction rate of up to 341 fmol SO₄²⁻ cell⁻¹ day⁻¹ was estimated. Thus, the small Desulfosporosinus population has the potential to reduce sulfate in situ at a rate of 4.0-36.8 nmol (g soil w. wt.)⁻¹ day⁻¹, sufficient to account for a considerable part of sulfate reduction in the peat soil. Modeling of sulfate diffusion to such highly active cells identified no limitation in sulfate supply even at bulk concentrations as low as 10 μM. Collectively, these data show that the identified Desulfosporosinus species, despite being a member of the 'rare biosphere', contributes to an important biogeochemical process that diverts the carbon flow in peatlands from methane to CO₂ and, thus, alters their contribution to global warming.

Show MeSH

Related in: MedlinePlus

Quantification of Desulfosporosinus 16S rRNA genes relative to total 16S rRNA genes of Bacteria and Archaea by quantitative real-time PCR. The relative abundance ± SD of Desulfosporosinus sp. was determined for pristine peat soil samples over the years 2004, 2006, and 2007 (10–20 cm depth; biological replicates, n=3) in comparison to SIP incubations with and without sulfate (technical replicates, n=3). Peat soil of the 10–20-cm depth horizon was also used for the SIP incubations.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4499578&req=5

Figure 4: Quantification of Desulfosporosinus 16S rRNA genes relative to total 16S rRNA genes of Bacteria and Archaea by quantitative real-time PCR. The relative abundance ± SD of Desulfosporosinus sp. was determined for pristine peat soil samples over the years 2004, 2006, and 2007 (10–20 cm depth; biological replicates, n=3) in comparison to SIP incubations with and without sulfate (technical replicates, n=3). Peat soil of the 10–20-cm depth horizon was also used for the SIP incubations.

Mentions: DNA replication of Desulfosporosinus sp. in the sulfate-reducing mesocosms was confirmed by quantitative PCR. While the abundance of Desulfosporosinus sp. in SIP incubations without sulfate mirrored the natural abundance over time (0.006% of total Bacteria and Archaea), it steadily increased to 0.2% (2 weeks 12C-substrate turnover determination and 2 weeks SIP incubation), 0.6% (2 weeks 12C-substrate incubation and 2 months SIP), and 3.1% (2 weeks 12C-substrate incubation and 6 months SIP) of total bacterial and archaeal 16S rRNA genes in the incubations with sulfate (Fig. 4). This result clearly corroborates the observations of the SIP study, which relies on the multiplication of active microorganisms to incorporate label into their DNA, and shows at the same time that the enrichment of Desulfosporosinus sp. in the intensively analyzed 2-month incubation was still minimal.


A 'rare biosphere' microorganism contributes to sulfate reduction in a peatland.

Pester M, Bittner N, Deevong P, Wagner M, Loy A - ISME J (2010)

Quantification of Desulfosporosinus 16S rRNA genes relative to total 16S rRNA genes of Bacteria and Archaea by quantitative real-time PCR. The relative abundance ± SD of Desulfosporosinus sp. was determined for pristine peat soil samples over the years 2004, 2006, and 2007 (10–20 cm depth; biological replicates, n=3) in comparison to SIP incubations with and without sulfate (technical replicates, n=3). Peat soil of the 10–20-cm depth horizon was also used for the SIP incubations.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4499578&req=5

Figure 4: Quantification of Desulfosporosinus 16S rRNA genes relative to total 16S rRNA genes of Bacteria and Archaea by quantitative real-time PCR. The relative abundance ± SD of Desulfosporosinus sp. was determined for pristine peat soil samples over the years 2004, 2006, and 2007 (10–20 cm depth; biological replicates, n=3) in comparison to SIP incubations with and without sulfate (technical replicates, n=3). Peat soil of the 10–20-cm depth horizon was also used for the SIP incubations.
Mentions: DNA replication of Desulfosporosinus sp. in the sulfate-reducing mesocosms was confirmed by quantitative PCR. While the abundance of Desulfosporosinus sp. in SIP incubations without sulfate mirrored the natural abundance over time (0.006% of total Bacteria and Archaea), it steadily increased to 0.2% (2 weeks 12C-substrate turnover determination and 2 weeks SIP incubation), 0.6% (2 weeks 12C-substrate incubation and 2 months SIP), and 3.1% (2 weeks 12C-substrate incubation and 6 months SIP) of total bacterial and archaeal 16S rRNA genes in the incubations with sulfate (Fig. 4). This result clearly corroborates the observations of the SIP study, which relies on the multiplication of active microorganisms to incorporate label into their DNA, and shows at the same time that the enrichment of Desulfosporosinus sp. in the intensively analyzed 2-month incubation was still minimal.

Bottom Line: Methane emission from peatlands contributes substantially to global warming but is significantly reduced by sulfate reduction, which is fuelled by globally increasing aerial sulfur pollution.For the identified Desulfosporosinus species a high cell-specific sulfate reduction rate of up to 341 fmol SO₄²⁻ cell⁻¹ day⁻¹ was estimated.Thus, the small Desulfosporosinus population has the potential to reduce sulfate in situ at a rate of 4.0-36.8 nmol (g soil w. wt.)⁻¹ day⁻¹, sufficient to account for a considerable part of sulfate reduction in the peat soil.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbial Ecology, University of Vienna, Wien, Austria.

ABSTRACT
Methane emission from peatlands contributes substantially to global warming but is significantly reduced by sulfate reduction, which is fuelled by globally increasing aerial sulfur pollution. However, the biology behind sulfate reduction in terrestrial ecosystems is not well understood and the key players for this process as well as their abundance remained unidentified. Comparative 16S rRNA gene stable isotope probing (SIP) in the presence and absence of sulfate indicated that a Desulfosporosinus species, which constitutes only 0.006% of the total microbial community 16S rRNA genes, is an important sulfate reducer in a long-term experimental peatland field site. Parallel SIP using dsrAB (encoding subunit A and B of the dissimilatory (bi)sulfite reductase) identified no additional sulfate reducers under the conditions tested. For the identified Desulfosporosinus species a high cell-specific sulfate reduction rate of up to 341 fmol SO₄²⁻ cell⁻¹ day⁻¹ was estimated. Thus, the small Desulfosporosinus population has the potential to reduce sulfate in situ at a rate of 4.0-36.8 nmol (g soil w. wt.)⁻¹ day⁻¹, sufficient to account for a considerable part of sulfate reduction in the peat soil. Modeling of sulfate diffusion to such highly active cells identified no limitation in sulfate supply even at bulk concentrations as low as 10 μM. Collectively, these data show that the identified Desulfosporosinus species, despite being a member of the 'rare biosphere', contributes to an important biogeochemical process that diverts the carbon flow in peatlands from methane to CO₂ and, thus, alters their contribution to global warming.

Show MeSH
Related in: MedlinePlus