Acetate, lactate, propionate, and isobutyrate as electron donors for iron and sulfate reduction in Arctic marine sediments, Svalbard

Finke, Niko; Vandieken, Verona; Jørgensen, Bo Barker

doi:10.1111/j.1574-6941.2006.00214.x

Cited by 137 publications

(117 citation statements)

References 78 publications

(137 reference statements)

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“…Acetate has been shown previously to be the most important volatile fatty acid in terms of concentration and turnover, and identified as important substrate for anaerobic terminal electron-accepting processes in marine sediments (Sørensen et al, 1981;Parkes et al, 1989;Fukui et al, 1997;Finke et al, 2007). The addition of 170 mM acetate per day to our incubations exceeded these low concentrations of acetate in the control without acetate and stimulated its mineralization (Figures 1 and 3).…”

Section: Resultssupporting

confidence: 49%

“…Acetate oxidation during the sediment incubations Control incubations of Gullmar Fjord and Ulleung Basin sediments that were not amended with acetate showed acetate concentrations o12 mM throughout the duration of the experiments (Figure 3) (not measured for Skagerrak incubations), which is at the lower end of reported concentrations for marine sediments (Sansone and Martens, 1982;Fukui et al, 1997;Wellsbury et al, 2002;Finke et al, 2007;Heuer et al, 2009). Acetate has been shown previously to be the most important volatile fatty acid in terms of concentration and turnover, and identified as important substrate for anaerobic terminal electron-accepting processes in marine sediments (Sørensen et al, 1981;Parkes et al, 1989;Fukui et al, 1997;Finke et al, 2007).…”

Section: Resultsmentioning

confidence: 90%

“…As acetate is an important electron donor for microbial iron and sulfate reduction in marine sediments (Sørensen et al, 1981;Parkes et al, 1989;Fukui et al, 1997;Finke et al, 2007), we chose ( 13 C-labeled) acetate as the substrate for RNA-SIP studies and MPN counts of manganese reducers.…”

Section: Introductionmentioning

confidence: 99%

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Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria

et al. 2012

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Dissimilatory manganese reduction dominates anaerobic carbon oxidation in marine sediments with high manganese oxide concentrations, but the microorganisms responsible for this process are largely unknown. In this study, the acetate-utilizing manganese-reducing microbiota in geographically well-separated, manganese oxide-rich sediments from Gullmar Fjord (Sweden), Skagerrak (Norway) and Ulleung Basin (Korea) were analyzed by 16S rRNA-stable isotope probing (SIP). Manganese reduction was the prevailing terminal electron-accepting process in anoxic incubations of surface sediments, and even the addition of acetate stimulated neither iron nor sulfate reduction. The three geographically distinct sediments harbored surprisingly similar communities of acetateutilizing manganese-reducing bacteria: 16S rRNA of members of the genera Colwellia and Arcobacter and of novel genera within the Oceanospirillaceae and Alteromonadales were detected in heavy RNA-SIP fractions from these three sediments. Most probable number (MPN) analysis yielded up to 10 6 acetate-utilizing manganese-reducing cells cm À 3 in Gullmar Fjord sediment. A 16S rRNA gene clone library that was established from the highest MPN dilutions was dominated by sequences of Colwellia and Arcobacter species and members of the Oceanospirillaceae, supporting the obtained RNA-SIP results. In conclusion, these findings strongly suggest that (i) acetatedependent manganese reduction in manganese oxide-rich sediments is catalyzed by members of taxa (Arcobacter, Colwellia and Oceanospirillaceae) previously not known to possess this physiological function, (ii) similar acetate-utilizing manganese reducers thrive in geographically distinct regions and (iii) the identified manganese reducers differ greatly from the extensively explored iron reducers in marine sediments.

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Section: Resultssupporting

confidence: 49%

Section: Resultsmentioning

confidence: 90%

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Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria

et al. 2012

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“…4 and 6, small size of box 3) indicate that the balance between production of these intermediates and their consumption was maintained at all temperatures. Specific inhibition experiments of sulfate reduction typically result in increasing VFA concentrations reaching over 1500 lM (Finke et al, 2007), between one and two orders of magnitude greater than the values measured in this study. If sulfate-reducing bacteria were more intolerant to higher temperatures than fermenting bacteria, VFA concentrations should have increased well above the 20-80 lM concentrations shown in Fig.…”

Section: Carbon Cycling Under Changed Temperature Regimes: Evidence Ocontrasting

confidence: 56%

Temperature induced decoupling of enzymatic hydrolysis and carbon remineralization in long-term incubations of Arctic and temperate sediments

Robador

Brüchert

Steen

et al. 2010

Geochimica et Cosmochimica Acta

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Extracellular enzymatic hydrolysis of high-molecular weight organic matter is the initial step in sedimentary organic carbon degradation and is often regarded as the rate-limiting step. Temperature effects on enzyme activities may therefore exert an indirect control on carbon mineralization. We explored the temperature sensitivity of enzymatic hydrolysis and its connection to subsequent steps in anoxic organic carbon degradation in long-term incubations of sediments from the Arctic and the North Sea. These sediments were incubated under anaerobic conditions for 24 months at temperatures of 0, 10, and 20°C. The short-term temperature response of the active microbial community was tested in temperature gradient block incubations. The temperature optimum of extracellular enzymatic hydrolysis, as measured with a polysaccharide (chondroitin sulfate), differed between Arctic and temperate habitats by about 8-13°C in fresh sediments and in sediments incubated for 24 months. In both Arctic and temperate sediments, the temperature response of chondroitin sulfate hydrolysis was initially similar to that of sulfate reduction. After 24 months, however, hydrolysis outpaced sulfate reduction rates, as demonstrated by increased concentrations of dissolved organic carbon (DOC) and total dissolved carbohydrates. This effect was stronger at higher incubation temperatures, particularly in the Arctic sediments. In all experiments, concentrations of volatile fatty acids (VFA) were low, indicating tight coupling between VFA production and consumption. Together, these data indicate that long-term incubation at elevated temperatures led to increased decoupling of hydrolytic DOC production relative to fermentation. Temperature increases in marine sedimentary environments may thus significantly affect the downstream carbon mineralization and lead to the increased formation of refractory DOC.

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“…This involvement is supported by observations that SRB are abundant in Arctic coastal marine sediments such as in Svalbard, Norway (Ravenschlag et al 2001), and in Antarctic sediments (Purdy et al 2003) and that psychrophilic SRB isolated from the same sediments actively reduced sulfate at in situ temperatures (Knoblauch et al 1999;Bruchert et al 2001). To the best of our knowledge, the role of FeRB in methylation in polar regions has not been explored though iron, like sulfate, reduction readily occurs in cold environments (Finke et al 2007). …”

Section: Methylation By Srb and Ferbmentioning

confidence: 71%

Some like it cold: microbial transformations of mercury in polar regions

2011

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The contamination of polar regions with mercury that is transported from lower latitudes as inorganic mercury has resulted in the accumulation of methylmercury (MeHg) in food chains, risking the health of humans and wildlife. While production of MeHg has been documented in polar marine and terrestrial environments, little is known about the responsible transformations and transport pathways and the processes that control them. We posit that as in temperate environments, microbial transformations play a key role in mercury geochemical cycling in polar regions by: (1) methylating mercury by one of four proposed pathways, some not previously described; (2) degrading MeHg by activities of mercury resistant and other bacteria; and (3) carrying out redox transformations that control the supply of the mercuric ion, the substrate of methylation reactions. Recent analyses have identified a high potential for mercury-resistant microbes that express the enzyme mercuric reductase to affect the production of gaseous elemental mercury when and where daylight is limited. The integration of microbially mediated processes in the paradigms that describe mercury geochemical cycling is therefore of high priority especially in light of concerns regarding the effect of global warming and permafrost thawing on input of MeHg to polar regions

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Acetate, lactate, propionate, and isobutyrate as electron donors for iron and sulfate reduction in Arctic marine sediments, Svalbard

Cited by 137 publications

References 78 publications

Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria

Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria

Temperature induced decoupling of enzymatic hydrolysis and carbon remineralization in long-term incubations of Arctic and temperate sediments

Some like it cold: microbial transformations of mercury in polar regions

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