Experimental modeling of the bacterial community translocation during freezing and thawing of peat permafrost soils of Western Siberia

Morgalev, Sergey; Morgaleva, Tamara; Morgalev, Yu; Loiko, Sergey V.; Manasypov, Rinat M.; Lim, Artem G.; Pokrovsky, Oleg S.

doi:10.1088/1755-1315/400/1/012017

Cited by 4 publications

(6 citation statements)

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“…The freezing of the peat core led to shifting of the initial peak of bacteria at 31 cm and the appearance of new pronounced maxima at 53 and 84 cm. The most likely explanation for this is bacterial exclusion from ice formation during two freezing front migrations resulting in cell concentration at the freezing fronts meeting point, as has been shown for algal suspensions (Morgalev et al, 2019). In addition, mobilization of cells from previously non-connected peat pores cannot be excluded.…”

Section: Discussionmentioning

confidence: 95%

“…Further subsampling was performed under sterile protected conditions in a laminar hood box (A100). The total number of microorganisms was determined in a Goryaev chamber (Morgalev et al, 2019). To determine the ratio of living and dead bacteria during freezing and repeated permafrost FTC, we modi ed the direct cell counting method by staining with the LIVE / DEAD™ BacLight™ Bacterial Viability Kit.…”

Section: Analyses and Statistical Treatmentmentioning

confidence: 99%

“…To determine the ratio of living and dead bacteria during freezing and repeated permafrost FTC, we modi ed the direct cell counting method by staining with the LIVE / DEAD™ BacLight™ Bacterial Viability Kit. This modi cation consisted of using a confocal microscope, for visually detecting the bacteria, counting their numbers and assessing the LIVE / DEAD ratio (Morgalev et al, 2019).…”

Section: Analyses and Statistical Treatmentmentioning

confidence: 99%

“…This peak was explained by freezing front migration and concentration of nutrients and certain groups of microorganisms at the bottom of the active layer. Forced translocation of microorganisms via freezing front migration has been evidenced in laboratory experiments on aqueous suspension (Morgalev et al, 2019). In peat cores for all permafrost zones in western Siberia, a strong local maximum of DOC, P, Ca, Fe and other trace element concentrations was recently found in ice sampled below the current active layer boundary (Lim et al, 2021).…”

Section: Introductionmentioning

confidence: 96%

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Fractionation of organic C, nutrients, metals and bacteria in peat porewater and ice after freezing and thawing

Morgalev

Lim

Morgaleva

et al. 2022

Environ Sci Pollut Res

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To better understand freezing -thawing cycles operating in peat soils of permafrost landscapes, we experimentally modelled bi-directional freezing and thawing of the three sections of 90-cm long peat core collected from a discontinuous permafrost zone in western Siberia. We measured translocation of microorganisms and changes in porewater chemistry (pH, UV absorbance, dissolved organic carbon (DOC), and major and trace element concentrations) after thawing and two-way freezing of peat cores. We demonstrate that bi-directional freezing and thawing of a peat core is capable of strongly modifying the vertical pattern of bacteria, DOC, nutrients, and trace element concentrations. Sizeable enrichment (a factor of 2 to 5) of DOC, macro-(P, K, Ca) and micro-nutrients (Ni, Mn, Co, Rb, B) and some low-mobile trace elements in several horizons of ice and peat porewater after freeze/thaw experiment may stem from physical disintegration of peat particles, leaching of peat constituents and opening of isolated (nonconnected) pores during freezing front migration. However, due to the appearance of multiple maxima of element concentration after a freeze-thaw event, the use of peat ice chemical composition as environmental archive for paleo-reconstructions is unwarranted.

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Section: Discussionmentioning

confidence: 95%

Section: Analyses and Statistical Treatmentmentioning

confidence: 99%

Section: Analyses and Statistical Treatmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

See 2 more Smart Citations

Fractionation of organic C, nutrients, metals and bacteria in peat porewater and ice after freezing and thawing

Morgalev

Lim

Morgaleva

et al. 2022

Environ Sci Pollut Res

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“…Although laboratory experiments allow for the identification of governing factors during freezing/thawing effects [36][37][38][39][40][41][42][43], their applications to naturally relevant aquatic settings of high latitude permafrost peatlands remain very restricted. Previous works in permafrost peatlands reported translocation of microorganisms and changes in porewater chemistry (pH, UV absorbance, DOC, major and trace element concentrations) after the thawing and bidirectional freezing of peat cores [44,45]. Another recent study examined the impact of freezing/thawing cycles (FTC) on the surface waters from Northeast European permafrost peatland [46].…”

Section: Introductionmentioning

confidence: 99%

Partitioning of Dissolved Organic Carbon, Major Elements, and Trace Metals during Laboratory Freezing of Organic Leachates from Permafrost Peatlands

et al. 2023

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Climate change is likely to modify the freezing–thawing cycles in soils and surface waters of permafrost-affected and subarctic regions. However, the change of solution chemical composition during ice formation and the evolution of the remaining fluids remain very poorly known. Towards a better understanding of dissolved (<0.45 µm) organic carbon, as well as major and trace element behavior in permafrost peatland environments, here we performed laboratory freezing of peat leachates, from complete freezing to complete thawing, in order to quantify the partitioning of solutes between the aqueous solution and the remaining ice. Freezing experiments were conducted, with and without polyurethane insulation. Two main types of experiments involved (i) progressive freezing, when we started from liquid leachates (filtered <0.45 µm) and allowed them to freeze at −18 °C, and (ii) progressive thawing, where first, we froze solid a series of <0.45 µm filtered leachates and then monitored their thawing at room temperature, 20 °C. We hypothesized the existence of two main groups of solutes, behaving conservatively or non-conservatively during freezing, depending on their incorporation into the ice or their ability to coagulate in the form of insoluble minerals or amorphous materials in the fluid phase. An unexpected result of this work was that, despite a sizable degree of element concentration in the remaining fluid and possible coagulation of organic, organo-mineral, and inorganic compounds, the freezing and subsequent thawing produced final concentrations of most solutes which were not drastically different from the initial concentrations in the original leachates prior to freezing. This demonstrates the high stability of dissolved (<0.45 µm) organic carbon, iron, aluminum, and some trace metals to the repetitive freezing and thawing of surface waters in permafrost peatlands.

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Dispersed ground ice of permafrost peatlands: Potential unaccounted carbon, nutrient and metal sources

et al. 2021

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Experimental modeling of the bacterial community translocation during freezing and thawing of peat permafrost soils of Western Siberia

Cited by 4 publications

References 4 publications

Fractionation of organic C, nutrients, metals and bacteria in peat porewater and ice after freezing and thawing

Fractionation of organic C, nutrients, metals and bacteria in peat porewater and ice after freezing and thawing

Partitioning of Dissolved Organic Carbon, Major Elements, and Trace Metals during Laboratory Freezing of Organic Leachates from Permafrost Peatlands

Dispersed ground ice of permafrost peatlands: Potential unaccounted carbon, nutrient and metal sources

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