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McKenzie, C.K.; Schiff, Sherry L.; Aravena, Ramón; Kelly, Carol A.; Louis, V. St.

doi:10.1023/a:1005416903368

Cited by 48 publications

(5 citation statements)

References 18 publications

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“…While the surface peat may be most sensitive to elevated temperatures [13,19,87], our findings support Dorrepaal et al [9]in showing that the deep C bank is indeed at risk under elevated temperatures as we found that temperature is indeed a factor limiting microbial activity in deep peat reserves in the S1 bog. However, additional factors such as low initial population sizes, substrate availability, etc.…”

Section: Role Of Microbial Communitysupporting

confidence: 89%

Constraints on microbial communities, decomposition and methane production in deep peat deposits

et al. 2020

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Section: Role Of Microbial Communitysupporting

confidence: 89%

Constraints on microbial communities, decomposition and methane production in deep peat deposits

et al. 2020

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“…The impact of temperature on the permafrost soil OM degradation has been intensively investigated, both in field soil heating experiments (Eliasson et al, 2005;Hartley et al, 2007;Melillo et al, 2002) and in laboratory incubations (Bracho et al, 2016;McKenzie et al, 1998). However, no strict consensus has been reached about the temperature control on soil OM degradation and significant controversies persist as discussed below.…”

Section: Doc Release From Frozen Peat At Different Temperaturesmentioning

confidence: 99%

Aerobic release and biodegradation of dissolved organic matter from frozen peat: Effects of temperature and heterotrophic bacteria

et al. 2020

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Understanding the conditions of dissolved organic matter (DOM) release from thawing peat in the Arctic regions and identifying the pathways of processing DOM by soil and aquatic heterotrophic bacteria are critical in the context of rapid climate change. Until now, experimental approaches did not allow quantitative predictions of temperature and biota effects on carbon release from peat in permafrost-affected aquatic environments. In this study, we incubated frozen peat and its aqueous leachate at various temperatures (4, 25 or 45°C), with and without culturable heterotrophic bacteria Iodobacter sp., extracted from thermokarst lakes, to quantify the release and the removal rate of organic carbon (OC) with time. The metabolic diversity of the native microbial community associated with the substrates involved in OC processing was also characterized. Transmission electron microscopy revealed that, after degradation, the associated bacteria are mostly located in the inner parts of plant cells, and that the degradation of organic matter around bacteria is more pronounced at 4 and 25°C compared to 45°C. The metabolic diversity of heterotrophic bacteria was equally high at 4 and 25°C, but lower at 45°C. Regardless of the microbial consortium (native community alone or with added culturable heterotrophs), both the OC release from peat and the OC removal from peat leachate by bacteria were similar at 4 and 25°C. Very low apparent activation energies of DOM biodegradation between 4 and 25°C (−4.23 ± 12.3 kJ mol − 1) suggest that the short-period of surface water warming in summer would have an insignificant effect on DOM microbial processing. Such duration (1-3 weeks) is comparable with the water residence time in peat depressions and permafrost subsidences, where peat degradation and DOM microbial processing occur. This questions the current paradigm of a drastic effect of temperature rise on organic carbon release from frozen peatlands, and should be considered for modelling short-term climate impacts in these regions.

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“…This important and extensive event of peat generation may have been sufficient to reverse regionally and temporarily the reduction trend in atmospheric CO 2 according to the global curves established by the GEOCARB model (Berner & Kothavala, 2001). Studies in present-day peatlands point out that this type of environment plays a significant role in the emission of greenhouse gases, especially under warming and flooding conditions (Billings et al, 1982;Aerts & Ludwig, 1997;McKenzie et al, 1998). On the other hand, the younger peat mires developed in the northern areas of the basin were very sparse and therefore insufficient to affect the general low trend in atmospheric CO 2 .…”

Section: P R O V a Smentioning

confidence: 99%

Variation in stomatal numbers of Glossopteris leaves from the Lower Permian of Paraná Basin, Brazil

Schmidt¹,

Guerra-Sommer²,

Bernardes-de-Oliveira³

2011

Rev. bras. paleontol.

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-The stomatal density and index in compressed leaves of Glossopteris communis from two different roof shales from the Lower Permian in Paraná Basin, Brazil (Western Gondwana) have been investigated to test the possible relationship with modeled global changes in atmospheric CO 2 during the Phanerozoic. The obtained parameters show that the genus Glossopteris from the Cool Temperate biome can be used as CO 2 -proxy, despite the impossibility of being compared with living relatives or equivalents. When confronted with already published data for the Tropical Summer Wet biome, the present results confirm the detection of low levels of atmospheric CO 2 during the Early Permian, as predicted by the modeled curve. Nevertheless, the lower stomatal numbers detected at the climax of the coal interval (Faxinal Coalfield, Sakmarian) when compared to the higher ones obtained in leaves from a younger interval (Figueira Coalfield, Artinskian) could be attributed to temporarily high levels of atmospheric CO 2 . Therefore, the occurrence of an extensive peat generating event at the southern part of the basin and subsequent greenhouse gases emissions from this environment may have been enough to reverse regionally and temporarily the reduction trend in atmospheric CO 2 . Additionally, the Faxinal flora is preserved in a tonstein layer, which is a record of volcanic activity that could also cause a rise in atmospheric CO 2 . During the Artinskian, the scarce generation of peat mires, as revealed by the occurrence of thin and discontinuous coal layers, and the lack of volcanism evidence would be insufficient to affect the general low CO 2 trend.Key words: paleo-CO 2 proxy, pteridosperms, fossil cuticles, Rio Bonito Formation, peat-forming floras, Gondwana.RESUMO -Frequências estomáticas foram calculadas em cutículas de Glossopteris communis, procedentes de dois afloramentos do Permiano Inferior na bacia do Paraná, com o objetivo de relacioná-las com variações na concentração atmosférica de CO 2 modeladas para o Fanerozoico. Os resultados indicam que as glossopterídeas do bioma Temperado Frio podem ser utilizadas como equivalentes climáticos para inferência de níveis de CO 2 paleoatmosférico, apesar da impossibilidade de estabelecer um equivalente ecológico atual. Quando confrontados com dados obtidos para o bioma Tropical de Verão Úmido, os resultados aqui apresentados confirmam a detecção de baixos níveis de CO 2 na atmosfera durante o período, de acordo com o modelamento da curva. Porém, as frequências estomáticas mais baixas detectadas no clímax do intervalo formador de carvão (jazida de Faxinal, Sakmariano), quando comparadas às frequências mais altas obtidas nas folhas de intervalo mais jovem (jazida de Figueira, Artinskiano), poderiam ser atribuídas a níveis temporariamente altos de CO 2 na atmosfera. A ocorrência de extenso evento gerador de turfa na parte sul da bacia, com a consequente emissão de gases-estufa deste ambiente, poderia ter sido suficiente para reverter a tendência de queda de CO 2 atmosférico em âmbi...

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Untitled

Cited by 48 publications

References 18 publications

Constraints on microbial communities, decomposition and methane production in deep peat deposits

Constraints on microbial communities, decomposition and methane production in deep peat deposits

Aerobic release and biodegradation of dissolved organic matter from frozen peat: Effects of temperature and heterotrophic bacteria

Variation in stomatal numbers of Glossopteris leaves from the Lower Permian of Paraná Basin, Brazil

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