Characterizing Dissolved Organic Matter and Other Water-Soluble Compounds in Ground Ice of the Russian Arctic: A Focus on Ground Ice Classification within the Carbon Cycle Context

Climate-induced changes contribute to the thawing of ice-rich permafrost in the Arctic, which leads to the release of large amounts of organic carbon into the atmosphere in the form of greenhouse gases, mainly carbon dioxide and methane. Ground ice constitutes a considerable volume of the cryogenica...

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Bibliographic Details
Published in:Geosciences
Main Authors: Petr Semenov, Anfisa Pismeniuk, Anna Kil, Elizaveta Shatrova, Natalia Belova, Petr Gromov, Sergei Malyshev, Wei He, Anastasiia Lodochnikova, Ilya Tarasevich, Irina Streletskaya, Marina Leibman
Format: Article in Journal/Newspaper
Language:English
Published: MDPI AG 2024
Subjects:
ground ice
dissolved organic matter
excitation–emission matrix fluorimetry
biogeochemical cycling
greenhouse gas emission
Geology
QE1-996.5
Bolshevik Island
Ice
permafrost
Severnaya Zemlya
Online Access:https://doi.org/10.3390/geosciences14030077
https://doaj.org/article/53e4cfad8f454f168764f5be137713ce
Description
Summary:Climate-induced changes contribute to the thawing of ice-rich permafrost in the Arctic, which leads to the release of large amounts of organic carbon into the atmosphere in the form of greenhouse gases, mainly carbon dioxide and methane. Ground ice constitutes a considerable volume of the cryogenically sequestered labile dissolved organic carbon (DOC) subjected to fast mineralization upon thawing. In this work, we collected a unique geochemical database of the ground and glacier ice comprising the samples from various geographic locations in the Russian Arctic characterized by a variety of key parameters, including ion composition, carbon-bearing gases (methane and carbon dioxide), bulk biogeochemical indicators, and fluorescent dissolved organic matter (DOM) fractions. Our results show that interaction with solid material—such as sediments, detritus, and vegetation—is likely the overriding process in enrichment of the ground ice in all the dissolved compounds. Terrigenous humic-like dissolved organic matter was predominant in all the analyzed ice samples except for glacier ice from Bolshevik Island (the Severnaya Zemlya archipelago) and pure (with low sediment content) tabular ground ice from western Yamal. The labile protein-like DOM showed no correlation to humic components and was probably linked to microbial abundance in the ground ice. The sum of the fluorophores deconvoluted by PARAFAC strongly correlates to DOC, which proves the potential of using this approach for differentiation of bulk DOC into fractions with various origins and biogeochemical behaviors. The pure tabular ground ice samples exhibit the highest rate of fresh easily degradable DOM in the bulk DOC, which may be responsible for the amplification of permafrost organic matter decomposition upon thawing.

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