A rusty carbon sink

Eglinton, T. I.

doi:10.1038/483165a

Cited by 38 publications

(28 citation statements)

References 5 publications

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“…Nevertheless, the mechanisms that control preservation and accumulation of OC in shelf sediments are complex and poorly characterized. Moving toward a more mechanistic insight on sorptive preservation, it was recently suggested that a substantial fraction of OC burial in marine sediments occur due to association with reactive iron phases [Eglinton, 2012;Lalonde et al, 2012]. Moving toward a more mechanistic insight on sorptive preservation, it was recently suggested that a substantial fraction of OC burial in marine sediments occur due to association with reactive iron phases [Eglinton, 2012;Lalonde et al, 2012].…”

Section: Introductionmentioning

confidence: 99%

“…Both OC-Fe coprecipitation and surface chelation transfers OC to the deeper anoxic sediment layers through sedimentation, physical reworking, and bioturbation. Extended research efforts are required to understand what OC is preferentially associating with reactive iron, the age and composition of the OC associated with iron oxides, and what is the larger-scale role of this OC-Fe process in the land-shelf carbon cycling [Eglinton, 2012;Lalonde et al, 2012;Riedel et al, 2013]. The OC-Fe associations are metastable over geological timescales [Lalonde et al, 2012;Schwertmann, 1966].…”

Section: Introductionmentioning

confidence: 99%

“…Many factors have been proposed, such as water column depth [Suess, 1980], sources and transport of organic matter [Goni et al, 2005;Luckge et al, 1996;Schubert and Stein, 1996], sediment accumulation rates [Muller and Suess, 1979], oxygen exposure time [Hartnett et al, 1998], cometabolization [Canfield, 1994], and sorption on mineral surfaces [Keil et al, 1994;Mayer, 1995]. Moving toward a more mechanistic insight on sorptive preservation, it was recently suggested that a substantial fraction of OC burial in marine sediments occur due to association with reactive iron phases [Eglinton, 2012;Lalonde et al, 2012].…”

Section: Introductionmentioning

confidence: 99%

“…The OC-Fe associations are metastable over geological timescales [Lalonde et al, 2012;Schwertmann, 1966]. Extended research efforts are required to understand what OC is preferentially associating with reactive iron, the age and composition of the OC associated with iron oxides, and what is the larger-scale role of this OC-Fe process in the land-shelf carbon cycling [Eglinton, 2012;Lalonde et al, 2012;Riedel et al, 2013].…”

Section: Introductionmentioning

confidence: 99%

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Organic carbon remobilized from thawing permafrost is resequestered by reactive iron on the Eurasian Arctic Shelf

Salvadó

Tesi

Andersson

et al. 2015

Geophysical Research Letters

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Given the potential for permafrost carbon (PF/C)‐climate feedbacks in the Siberian‐Arctic land‐ocean system, there is a need for understanding the fate of thawed‐out PF/C. Here we show that the sequestration of OC by reactive iron (OC‐Fe) ranges between 0.5 and 22% on the Eurasian Arctic Shelf, with higher values in the Kara Sea (KS) (18 ± 6%) and the Laptev Sea (LS) (14 ± 4%). The Δ14C/δ13C signatures of the OC‐Fe are substantially older and more terrestrial than the bulk sediment OC in the LS but younger and more dominated by marine plankton sources in the East Siberian Sea (ESS). Statistical source apportionment modeling reveal that reactive iron phases resequestered 15 ± 5% of thawing PF/C in the LS and 6.4 ± 5% in the ESS, derived from both coastal erosion of ice complex deposit and thawing topsoil. This Fe‐associated trap of PF/C constitutes a reduction of the degradation/outgassing and thus also an attenuation of the PF/C‐climate feedback.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Organic carbon remobilized from thawing permafrost is resequestered by reactive iron on the Eurasian Arctic Shelf

Salvadó

Tesi

Andersson

et al. 2015

Geophysical Research Letters

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“…Pelagic aggregates become hotspots for microbial processes and are important for the turnover and sinking flux of organic and inorganic matter to the sediment (8,9). Reactive iron species are important for stabilizing organic matter in ocean and freshwater sediments, pointing to a tight coupling between the biogeochemical cycles of carbon and iron (10). However, we have only a limited understanding of the iron redox reactions occurring in these aggregates before they reach the sediment.…”

mentioning

confidence: 99%

Insights into the Structure and Metabolic Function of Microbes That Shape Pelagic Iron-Rich Aggregates (“Iron Snow”)

Chourey

Reiche

et al. 2013

Appl Environ Microbiol

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dMicrobial ferrous iron [Fe(II)] oxidation leads to the formation of iron-rich macroscopic aggregates ("iron snow") at the redoxcline in a stratified lignite mine lake in east-central Germany. We aimed to identify the abundant Fe-oxidizing and Fe-reducing microorganisms likely to be involved in the formation and transformation of iron snow present in the redoxcline in two basins of the lake that differ in their pH values. Nucleic acid-and lipid-stained microbial cells of various morphologies detected by confocal laser scanning microscopy were homogeneously distributed in all iron snow samples. The dominant iron mineral appeared to be schwertmannite, with shorter needles in the northern than in the central basin samples. Total bacterial 16S rRNA gene copies ranged from 5.0 ؋ 10 8 copies g (dry weight) ؊1 in the acidic central lake basin (pH 3.3) to 4.0 ؋ 10 10 copies g (dry weight) ؊1 in the less acidic (pH 5.9) northern basin. Total RNA-based quantitative PCR assigned up to 61% of metabolically active microbial communities to Fe-oxidizing-and Fe-reducing-related bacteria, indicating that iron metabolism was an important metabolic strategy. Molecular identification of abundant groups suggested that iron snow surfaces were formed by chemoautotrophic iron oxidizers, such as Acidimicrobium, Ferrovum, Acidithiobacillus, Thiobacillus, and Chlorobium, in the redoxcline and were rapidly colonized by heterotrophic iron reducers, such as Acidiphilium, Albidiferax-like, and Geobacter-like groups. Metaproteomics yielded 283 different proteins from northern basin iron snow samples, and protein identification provided a glimpse into some of their in situ metabolic processes, such as primary production (CO 2 fixation), respiration, motility, and survival strategies.

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Thermokarst processes increase the supply of stabilizing surfaces and elements (Fe, Mn, Al, and Ca) for mineral–organic carbon interactions

Monhonval

Strauß

Thomas

et al. 2022

Permafrost & Periglacial

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The stabilizing properties of mineral-organic carbon (OC) interactions have been studied in many soil environments (temperate soils, podzol lateritic soils, and paddy soils). Recently, interest in their role in permafrost regions is increasing as permafrost was identified as a hotspot of change. In thawing ice-rich permafrost regions, such as the Yedoma domain, 327-466 Gt of frozen OC is buried in deep sediments. Interactions between minerals and OC are important because OC is located very near the mineral matrix. Mineral surfaces and elements could mitigate recent and future greenhouse gas emissions through physical and/or physicochemical protection of OC. The dynamic changes in redox and pH conditions associated with thermokarst lake formation and drainage trigger metal-oxide dissolution and precipitation, likely influencing OC stabilization and microbial mineralization. However, the influence of thermokarst processes on mineral-OC interactions remains poorly constrained. In this study, we aim to characterize Fe, Mn, Al, and Ca minerals and their potential protective role for OC. Total and selective extractions were used to assess the crystalline and amorphous oxides or complexed metal pools as well as the organic acids found within these pools. We analyzed four sediment cores from an ice-rich permafrost area in Central Yakutia, which were drilled (i) in undisturbed Yedoma uplands, (ii) beneath a recent lake formed within Yedoma deposits, (iii) in a drained thermokarst lake basin, and (iv) beneath a mature thermokarst lake from the early Holocene period. We find a decrease in the amount of reactive Fe, Mn, Al, and Ca in the deposits on lake formation (promoting reduction reactions), and this was largely balanced by an increase in the amount of reactive metals in the deposits on lake drainage (promoting oxidation reactions). We demonstrate an increase in the metal to C molar ratio on thermokarst process, which may indicate an increase in metal-C bindings and could provide a higher protective role against microbial mineralization of organic matter. Finally, we find that an increase in mineral-OC interactions corresponded to a decrease in CO 2 and CH 4 gas emissions on thermokarst process.

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A rusty carbon sink

Cited by 38 publications

References 5 publications

Organic carbon remobilized from thawing permafrost is resequestered by reactive iron on the Eurasian Arctic Shelf

Organic carbon remobilized from thawing permafrost is resequestered by reactive iron on the Eurasian Arctic Shelf

Insights into the Structure and Metabolic Function of Microbes That Shape Pelagic Iron-Rich Aggregates (“Iron Snow”)

Thermokarst processes increase the supply of stabilizing surfaces and elements (Fe, Mn, Al, and Ca) for mineral–organic carbon interactions

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