Control of organic carbon mineralization by alternative electron acceptors in four peatlands, Central New York State, USA

Dettling, Mark D.; Yavitt, Joseph B.; Zinder, Stephen H.

doi:10.1672/0277-5212(2006)26[917:coocmb]2.0.co;2

Cited by 43 publications

(39 citation statements)

References 59 publications

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“…The low Fe(III) reduction rates corresponded to the low amounts of oxalate extractable Fe(III) oxides present in the upland fen and indicated that Fe(III) reduction was of minor significance for the oxidation of carbon in this fen similar to other northern peatlands (Blodau et al, 2002). Porewater profiles of Fe(II) and sulfate in the intermittent seep were similar to pH neutral fens (Todorova et al, 2005;Dettling et al, 2006) or other wetlands (Roden and Wetzel, 2003). The high Fe(II) formation rate at the seep suggested a mobilization of Fe(II) during waterlogging from autumn to spring.…”

Section: Mobilization and Oxidation Of Fe(ii) In The Catchmentmentioning

confidence: 72%

“…Atmospheric nitrogen and sulfate depositions might further enhance the activity of sulfate and nitrate reducers under changed climatic conditions in northern peatlands similar to other wetlands (Gauci et al, 2002;Lamers et al, 2002;Vile et al, 2003). However, addition of alternative electron acceptors to ombrotrophic bogs and minerotrophic fens incubated in anoxic jars do not universally divert carbon and electron flow from CH 4 formation (Dettling et al, 2006). δ 34 S values and 35 S-labeling patterns indicate that the dissimilatory reduction of sulfate is an ongoing process in acidic seeps and fens of a forested catchment in northern Bavaria, Germany (Lehstenbach, Fichtelgebirge) (Alewell and Giesemann, 1996;Alewell and Novak, 2001) like in peat bogs (Wieder and Lang, 1988).…”

Section: Introductionmentioning

confidence: 97%

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Microbial reduction of iron and porewater biogeochemistry in acidic peatlands

et al. 2008

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Abstract. Temporal drying of upper soil layers of acidic methanogenic peatlands might divert the flow of reductants from CH4 formation to other electron-accepting processes due to a renewal of alternative electron acceptors. In this study, we evaluated the in situ relevance of Fe(III)-reducing microbial activities in peatlands of a forested catchment that differed in their hydrology. Intermittent seeps reduced sequentially nitrate, Fe(III), and sulfate during periods of water saturation. Due to the acidic soil conditions, released Fe(II) was transported with the groundwater flow and accumulated as Fe(III) in upper soil layers of a lowland fen apparently due to oxidation. Microbial Fe(III) reduction in the upper soil layer accounted for 26.7 and 71.6% of the anaerobic organic carbon mineralization in the intermittent seep and the lowland fen, respectively. In an upland fen not receiving exogenous Fe, Fe(III) reduction contributed only to 6.7%. Fe(II) and acetate accumulated in deeper porewater of the lowland fen with maximum concentrations of 7 and 3 mM, respectively. Both supplemental glucose and acetate stimulated the reduction of Fe(III) indicating that fermentative, incomplete, and complete oxidizers were involved in Fe(II) formation in the acidic fen. Amplification of DNA yielded PCR products specific for Acidiphilium-, Geobacter-, and Geothrix-, but not for Shewanella- or Anaeroromyxobacter-related sequences. Porewater biogeochemistry observed during a 3-year-period suggests that increased drought periods and subsequent intensive rainfalls due to global climate change will further favor Fe(III) and sulfate as alternative electron acceptors due to the storage and enhanced re-oxidation of their reduced compounds in the soil.

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Section: Mobilization and Oxidation Of Fe(ii) In The Catchmentmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 97%

Microbial reduction of iron and porewater biogeochemistry in acidic peatlands

et al. 2008

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“…Yavitt and Seidmann-Zager, 2006). Drying and rewetting raised the ratio to as much as 61 for DW-D and 106 for DW-V, thus shifting respiratory activity away from methanogenesis as found in previous work (Achtnich et al, 1995;Dettling et al, 2006). Calculated from the isotope mass balance (Eqs.…”

Section: Impact Of Drying and Rewetting On Anaerobic And Aerobic Respmentioning

confidence: 73%

“…Our study demonstrated that almost the complete soil CO 2 pool must have been renewed, as the isotopic composition after rewetting matched the δ 13 C of the solid phase, thus differing substantially from the isotopic composition before drought. Upon interpretation, the suggested origin of this result is caused by the drought-induced, temporal suppression of methanogens after rewetting due to consumption of alternative electron acceptors (Achtnich et al, 1995;Dettling et al, 2006). Therefore, the fractionating effect of methanogens on δ 13 C CO 2 was temporarily suppressed, and δ 13 C CO 2 approached the isotopic signature of the solid phase.…”

Section: Respiration and Methanogenesismentioning

confidence: 96%

“…Under fluctuating hydrological conditions, an apparent coexistence of different redox processes was observed (Paul et al, 2006). Furthermore, the addition of alternative electron acceptors did not always inhibit CH 4 production (Dettling et al, 2006;Blodau and Moore, 2003b). Some methanogens were suggested to be able to shift to Published by Copernicus Publications on behalf of the European Geosciences Union.…”

Section: Introductionmentioning

confidence: 99%

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Fluxes and <sup>13</sup>C isotopic composition of dissolved carbon and pathways of methanogenesis in a fen soil exposed to experimental drought

2008

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Abstract. Peatlands contain a carbon stock of global concern and significantly contribute to the global methane burden. The impact of drought and rewetting on carbon cycling in peatland ecosystems is thus currently debated. We studied the impact of experimental drought and rewetting on intact monoliths from a temperate fen over a period of ~300 days, using a permanently wet treatment and two treatments undergoing drought for 50 days. In one of the mesocosms, vegetation had been removed. Net production of CH4 was calculated from mass balances in the peat and emission using static chamber measurements. Results were compared to 13C isotope budgets of CO2 and CH4 and energy yields of acetoclastic and hydrogenotrophic methanogenesis. Drought retarded methane production after rewetting for days to weeks and promoted methanotrophic activity. Based on isotope and flux budgets, aerobic soil respiration contributed 32–96% in the wet treatment and 86–99% in the other treatments. Drying and rewetting did not shift methanogenic pathways according to δ13C ratios of CH4 and CO2. Although δ13C ratios indicated a prevalence of hydrogenotrophic methanogenesis, free energies of this process were small and often positive on the horizon scale. This suggests that methane was produced very locally. Fresh plant-derived carbon input apparently supported respiration in the rhizosphere and sustained methanogenesis in the unsaturated zone, according to a 13C-CO2 labelling experiment. The study documents that drying and rewetting in a rich fen soil may have little effect on methanogenic pathways, but result in rapid shifts between methanogenesis and methanotrophy. Such shifts may be promoted by roots and soil heterogeneity, as hydrogenotrophic methanogenesis occurred locally even when conditions were not conducive for this process in the bulk peat.

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Controls on dissolved organic matter concentrations in soils and streams from a forested wetland and sloping bog in southeast Alaska

et al. 2010

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Understanding the sources and removal mechanisms for dissolved organic matter (DOM) in soils is critical to determining the importance of peatlands in influencing streamwater DOM concentrations. Soil saturation and soil temperature are the primary factors that influence DOM cycling in soils, but the relationships among these factors vary by soil type and climate. Despite the extent of peatlands that occur within Pacific coastal temperate rainforest (CTR) watersheds, there is little information describing how DOM storage and export patterns are related to soil saturation and temperature in the region. We measured soil water tables, soil temperatures and redox potential and compared these measurements to fluctuations in dissolved organic carbon (DOC) and nitrogen (DON) concentrations in a forested wetland and sloping bog in southeast Alaska to address this key information gap. DOC concentrations ranged from 5 to 140 mg C l 1 in wetland soils, 11 to 46 mg C l 1 in streams, and varied greatly in response to changes in water table, redox potential and soil temperature. Similarly, DON concentrations ranged from 0Ð03 to 2Ð4 mg N l 1 in wetland soils, 0Ð2 to 0Ð6 mg N l 1 in streams and concentrations also reflected seasonal changes in physical measures. Depth to water table and soil temperature were significant factors related to the concentration of DOC in forested wetland soils and streams, while soil temperature was a significant factor that influenced stream DOC and DON concentrations. Comparing soil solution and stream DOM concentrations indicated that N is retained in bogs, while both dilution and biotic/abiotic retention mechanisms control DOM export in forested wetlands. The relationships among soil saturation, temperature and concentrations of DOC and DON provide preliminary models for estimating DOM fluxes from wetland soils in the CTR. Furthermore, these results can help calibrate regional watershed carbon flux models to predict the potential impacts of climate shifts and management activities on future wetland soil and stream DOM concentrations in CTR watersheds.

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Control of organic carbon mineralization by alternative electron acceptors in four peatlands, Central New York State, USA

Cited by 43 publications

References 59 publications

Microbial reduction of iron and porewater biogeochemistry in acidic peatlands

Microbial reduction of iron and porewater biogeochemistry in acidic peatlands

Fluxes and <sup>13</sup>C isotopic composition of dissolved carbon and pathways of methanogenesis in a fen soil exposed to experimental drought

Controls on dissolved organic matter concentrations in soils and streams from a forested wetland and sloping bog in southeast Alaska

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Control of organic carbon mineralization by alternative electron acceptors in four peatlands, Central New York State, USA

Cited by 43 publications

References 59 publications

Microbial reduction of iron and porewater biogeochemistry in acidic peatlands

Microbial reduction of iron and porewater biogeochemistry in acidic peatlands

Fluxes and &lt;sup&gt;13&lt;/sup&gt;C isotopic composition of dissolved carbon and pathways of methanogenesis in a fen soil exposed to experimental drought

Controls on dissolved organic matter concentrations in soils and streams from a forested wetland and sloping bog in southeast Alaska

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Fluxes and <sup>13</sup>C isotopic composition of dissolved carbon and pathways of methanogenesis in a fen soil exposed to experimental drought