scholarly journals Microbial lipid signatures and substrate potential of organic matter in permafrost deposits: Implications for future greenhouse gas production

2016 ◽  
Vol 121 (10) ◽  
pp. 2652-2666 ◽  
Author(s):  
J. G. Stapel ◽  
L. Schirrmeister ◽  
P. P. Overduin ◽  
S. Wetterich ◽  
J. Strauss ◽  
...  
Keyword(s):  
Organic Matter ◽  
Greenhouse Gas ◽  
Gas Production ◽  
Microbial Lipid ◽  
Substrate Potential

scholarly journals Substrate potential of Eemian to Holocene permafrost organic matter for future microbial greenhouse gas production

2017 ◽  
Author(s):  
Janina G. Stapel ◽  
Georg Schwamborn ◽  
Lutz Schirrmeister ◽  
Brian Horsfield ◽  
Kai Mangelsdorf
Keyword(s):  
Organic Matter ◽  
Microbial Communities ◽  
Greenhouse Gas ◽  
Gas Production ◽  
Last Interglacial ◽  
Gas Generation ◽  
The Holocene ◽  
Substrate Potential ◽  
Mis 3 ◽  
Mis 5E

Abstract. Multiple permafrost cores from Bol'shoy Lyakhovsky Island in NE Siberia comprising deposits from Eemian to modern time are investigated to evaluate the stored potential of the freeze-locked organic matter (OM) to serve as substrate for the production of microbial greenhouse gases from thawing permafrost deposits. Deposits from Late Pleistocene glacial periods (comprising MIS 3 and MIS 4) possess an increased aliphatic character and a higher amount of potential substrates, and therefore higher OM quality in terms of biodegradation compared to interglacial deposits from the Eemian (MIS 5e) as well as from the Holocene (MIS 1). To assess the potential of the individual permafrost deposits to provide substrates for microbially induced greenhouse gas generation, concentrations of free and bound acetate as an excellent substrate for methanogenesis are used. The highest free (in pore water and segregated ice) and bound (bound to the organic matrix) acetate-substrate pools of the permafrost deposits are observed within the interstadial MIS 3 and stadial MIS 4 period deposits. In contrast, deposits from the last interglacial MIS 5e show only poor substrate pools. The Holocene deposits reveal a significant bound-acetate pool, representing at least a future substrate potential upon release during OM degradation. Biomarkers for past microbial communities (branched and isoprenoid GDGTs) show also highest abundance of past microbial communities during the MIS 3 and MIS 4 deposits, which indicates higher OM quality with respect to microbial degradation during time of deposition. On a broader perspective, Arctic warming will increase permafrost thaw and favour substrate availability from freeze-locked older permafrost deposits. Therefore, especially those deposits from MIS 3 and MIS 4 show a high potential for providing substrates relevant for methanogenesis.

scholarly journals Substrate potential of last interglacial to Holocene permafrost organic matter for future microbial greenhouse gas production

2018 ◽  
Vol 15 (7) ◽  
pp. 1969-1985 ◽  
Author(s):  
Janina G. Stapel ◽  
Georg Schwamborn ◽  
Lutz Schirrmeister ◽  
Brian Horsfield ◽  
Kai Mangelsdorf
Keyword(s):  
Organic Matter ◽  
Greenhouse Gas ◽  
Methanogenic Archaea ◽  
Organic Matrix ◽  
Gas Production ◽  
Last Interglacial ◽  
Substrate Potential ◽  
Mis 3 ◽  
Thawing Permafrost ◽  
Mis 5E

Abstract. In this study the organic matter (OM) in several permafrost cores from Bol'shoy Lyakhovsky Island in NE Siberia was investigated. In the context of the observed global warming the aim was to evaluate the potential of freeze-locked OM from different depositional ages to act as a substrate provider for microbial production of greenhouse gases from thawing permafrost. To assess this potential, the concentrations of free and bound acetate, which form an appropriate substrate for methanogenesis, were determined. The largest free-acetate (in pore water) and bound-acetate (organic-matrix-linked) substrate pools were present in interstadial marine isotope stage (MIS) 3 and stadial MIS 4 Yedoma permafrost deposits. In contrast, deposits from the last interglacial MIS 5e (Eemian) contained only a small pool of substrates. The Holocene (MIS 1) deposits revealed a significant bound-acetate pool, representing a future substrate potential upon release during OM degradation. Additionally, pyrolysis experiments on the OM allocated an increased aliphatic character to the MIS 3 and 4 Late Pleistocene deposits, which might indicate less decomposed and presumably more easily degradable OM. Biomarkers for past microbial communities, including those for methanogenic archaea, also showed the highest abundance during MIS 3 and 4, which indicated OM-stimulated microbial degradation and presumably greenhouse gas production during time of deposition. On a broader perspective, Arctic warming will increase and deepen permafrost thaw and favor substrate availability from older freeze-locked permafrost deposits. Thus, the Yedoma deposits especially showed a high potential for providing substrates relevant for microbial greenhouse gas production.

scholarly journals Wetland Sediments Host Diverse Microbial Taxa Capable of Cycling Alcohols

2019 ◽  
Vol 85 (12) ◽  
Author(s):  
Paula Dalcin Martins ◽  
Jeroen Frank ◽  
Hugh Mitchell ◽  
Lye Meng Markillie ◽  
Michael J. Wilkins
Keyword(s):  
Organic Matter ◽  
Alcohol Dehydrogenase ◽  
Greenhouse Gas ◽  
Significant Proportion ◽  
Gas Production ◽  
Organic Matter Degradation ◽  
Prairie Pothole ◽  
Alcohol Dehydrogenases ◽  
Fermentation Products ◽  
Alcohol Production

ABSTRACTAlcohols are commonly derived from the degradation of organic matter and yet are rarely measured in environmental samples. Wetlands in the Prairie Pothole Region (PPR) support extremely high methane emissions and the highest sulfate reduction rates reported to date, likely contributing to a significant proportion of organic matter mineralization in this system. While ethanol and isopropanol concentrations up to 4 to 5 mM in PPR wetland pore fluids have been implicated in sustaining these high rates of microbial activity, the mechanisms that support alcohol cycling in this ecosystem are poorly understood. We leveraged metagenomic and transcriptomic tools to identify genes, pathways, and microorganisms potentially accounting for alcohol cycling in PPR wetlands. Phylogenetic analyses revealed diverse alcohol dehydrogenases and putative substrates. Alcohol dehydrogenase and aldehyde dehydrogenase genes were included in 62 metagenome-assembled genomes (MAGs) affiliated with 16 phyla. The most frequently encoded pathway (in 30 MAGs) potentially accounting for alcohol production was aPyrococcus furiosus-like fermentation which can involve pyruvate:ferredoxin oxidoreductase (PFOR). Transcripts for 93 of 137 PFOR genes in these MAGs were detected, as well as for 158 of 243 alcohol dehydrogenase genes retrieved from these same MAGs. Mixed acid fermentation and heterofermentative lactate fermentation were also frequently encoded. Finally, we identified 19 novel putative isopropanol dehydrogenases in 15 MAGs affiliated withProteobacteria,Acidobacteria,Chloroflexi,Planctomycetes,Ignavibacteriae,Thaumarchaeota, and the candidate divisions KSB1 andRokubacteria. We conclude that diverse microorganisms may use uncommon and potentially novel pathways to produce ethanol and isopropanol in PPR wetland sediments.IMPORTANCEUnderstanding patterns of organic matter degradation in wetlands is essential for identifying the substrates and mechanisms supporting greenhouse gas production and emissions from wetlands, the main natural source of methane in the atmosphere. Alcohols are common fermentation products but are poorly studied as key intermediates in organic matter degradation in wetlands. By investigating genes, pathways, and microorganisms potentially accounting for the high concentrations of ethanol and isopropanol measured in Prairie Pothole wetland sediments, this work advanced our understanding of alcohol fermentations in wetlands linked to extremely high greenhouse gas emissions. Moreover, the novel alcohol dehydrogenases and microbial taxa potentially involved in alcohol metabolism may serve biotechnological efforts in bioengineering commercially valuable alcohol production and in the discovery of novel isopropanol producers or isopropanol fermentation pathways.

The molecular composition of dissolved organic matter (DOM) and its effects on the greenhouse gas production in pristine subarctic rivers

2020 ◽  
Author(s):  
Taija Saarela ◽  
Helena Jäntti ◽  
Mizue Ohashi ◽  
Jun’ichiro Ide ◽  
Frank Berninger ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Greenhouse Gas ◽  
Gas Production ◽  
Molecular Composition ◽  
Ion Cyclotron Resonance ◽  
Finnish Lapland ◽  
Receiving Waters ◽  
Spring Flow ◽  
Clearwater River

<p>Controls on the degradation of dissolved organic matter (DOM) in freshwaters play a major role in the global carbon cycle. Under the changing climate, the aquatic systems are exposed to increasing terrestrial OM load due to changes in precipitation and air temperature. However, little is known about how the source and composition of this DOM influence its microbial processing in receiving waters.</p><p>In this study, we aimed to determine the composition of riverine DOM at a molecular level to gain a more comprehensive understanding on how the quality and quantity of DOM reflect its microbial degradability. Our objectives were to determine how the DOM decay patterns differ between brown-water and clearwater river and how these further regulate the potential greenhouse gas production (carbon dioxide, CO<sub>2</sub> and methane, CH<sub>4</sub>) in these waters.</p><p>We collected water samples during two sampling occasions (June and October 2018) from two pristine subarctic rivers in Finnish Lapland and conducted 21-day incubation studies to follow the changes in the concentration and molecular composition of DOM, as well as the changes in the CO<sub>2</sub> and CH<sub>4</sub> concentrations. The molecular characterization of DOM was carried out using electrospray ionization (ESI) coupled to high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS).</p><p>Both rivers acted as a source of CO<sub>2</sub> and CH<sub>4</sub>. Our preliminary results show that river water surrounded by peatlands contained a higher number of compounds such as condensed aromatic structures and lignin-like molecules, which led to slower decomposition rates compared to DOM in clearwater river. Overall, the decomposition of DOM was higher during spring flow than during fall due to recently released fresh DOM in the water.</p>

scholarly journals Dissolved organic carbon, CO2, and CH4 concentrations and their stable isotope ratios in thermokarst lakes on the Qinghai-Tibetan Plateau

2016 ◽  
Author(s):  
Cuicui Mu ◽  
Tingjun Zhang ◽  
Qingbai Wu ◽  
Xiaoqing Peng ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Tibetan Plateau ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Greenhouse Gas ◽  
Lake Sediments ◽  
Thermal Stratification ◽  
Gas Production ◽  
Stable Isotope Ratios ◽  
Thermokarst Lakes

<p>Thermokarst lakes are widely distributed on the Qinghai-Tibetan Plateau (QTP), which accounts for 8% of the global permafrost area. These lakes probably promote organic matter biodegradation and thus accelerate the emission of carbon-based greenhouse gases. However, little is known about greenhouse gas concentrations and their stable isotopes characteristics of these lakes. In this study, we measured the concentrations of dissolved organic carbon (DOC), dissolved CO<sub>2</sub> and CH<sub>4</sub>, as well as the distribution of δ<sup>13</sup>C<sub>C</sub><sub>O2</sub>, δ<sup>13</sup>C<sub>C</sub><sub>H4</sub>, and δ<sup>13</sup>C<sub>OM</sub> (organic matter) of lake sediments in thermokarst lakes on the QTP. Results showed that the OM of the lake sediments was highly decomposed. The concentrations of DOC, CO<sub>2</sub> and CH<sub>4</sub> in the lake water on the QTP were 1.2–49.6 mg L<sup>–1</sup>, 3.6–45.0 μmol L<sup>–1</sup> and 0.28–3.0 μmol L<sup>–1</sup>, respectively. The highest CO<sub>2</sub> and CH<sub>4</sub> concentrations were recorded in July while the lowest values in September, which suggested that temperature had an effect on greenhouse gas production, although this pattern may also relate to thermal stratification of the water column. The results implied that thermokast lakes should be paid more attention to regarding carbon cycle and greenhouse gas emissions on the QTP.</p>

Processes affecting greenhouse gas production in experimental boreal reservoirs

2013 ◽  
Vol 27 (2) ◽  
pp. 567-577 ◽  
Author(s):  
Jason J. Venkiteswaran ◽  
Sherry L. Schiff ◽  
Vincent L. St. Louis ◽  
Cory J. D. Matthews ◽  
Natalie M. Boudreau ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Gas Production
Sign in / Sign up

Export Citation Format

Share Document