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

• Published in: Environmental Science and Pollution Research
• Main Authors: Morgalev, Sergey Yu, Lim, Artem, G, Morgaleva, Tamara, G, Morgalev, Yuri, N, Manasypov, Rinat, M, Kuzmina, Daria, Shirokova, Liudmila, S, Orgogozo, Laurent, Loiko, Sergey, V, Pokrovsky, Oleg, S
• Other Authors: Tomsk State University Tomsk, Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS), ANR-19-CE46-0003,HiPerBorea,Calul haute performance pour la quantification des impacts du changement climatique sur les régions boréales(2019)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: Peat; Pore water; Freezing; Thawing; Major elements; Trace elements; Nutrients; Toxicants; Microorganims; [SDE]Environmental Sciences; Ice; permafrost; Siberia
• Online Access: https://hal.science/hal-04290503; https://hal.science/hal-04290503/document; https://hal.science/hal-04290503/file/Morgalev_et_al_2022_Fractionation_of_Organic_C_Nutrients_Metals_And_Ba.pdf; https://doi.org/10.1007/s11356-022-22219-1

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.