Mats Rouven Ippach

• Lu, Xiang; Clayer, Francois; Dörsch, Peter; Hessen, Dag Olav; Brandt, Uta & Ippach, Mats Rouven [Show all 8 contributors for this article] (2026). In-Lake GHG Production Constrained by Lake DOM Mass Balance in a Boreal Catchment. Water Resources Research. ISSN 0043-1397. 62(5). doi: 10.1029/2025WR041297. Full text in Research Archive
• Pismeniuk, Anfisa; Dörsch, Peter; Ippach, Mats Rouven; Willmes, Clarissa; Sheffield, Sunniva Bratli & Pirk, Norbert [Show all 7 contributors for this article] (2026). Wintertime production and storage of methane in thermokarst ponds of subarctic Norway. Biogeosciences. ISSN 1726-4170. 23(4), p. 1497–1514. doi: 10.5194/bg-23-1497-2026. Full text in Research Archive Show summary

  The ongoing climate change in permafrost areas can trigger abrupt thaw processes, leading to the formation of thermokarst lakes and ponds. These water bodies, especially in organic-rich areas, are recognized as strong methane (CH4) emitters during the ice-free periods and have the potential to accumulate large CH4 amounts in and below the ice, which is released during the ice melt. We estimated winter CH4 bottom flux in nine shallow ponds within two permafrost peatlands in Northern Norway, Iškoras and Áidejávri, during the 2023–2024 ice cover season. The cumulative winter CH4 bottom flux ranged from 0.6 to 24 g CH4-C m−2 which at the Iškoras site contributed up to 40 % to the annual CH4 budget. The heterogeneity of the CH4 wintertime accumulation is related to pond depth, differences in vegetation, and the thermokarst pond formation age. The latter was investigated using a space-for-time substitution approach along chronosequences of thermokarst formation spanning more than 70 years. The winter CH4 bottom flux increased from 2 mg CH4-C m−2 d−1 in two-year-old pond to 106 mg CH4-C m−2 d−1 in a pond formed between 30 and 60 years ago. Pond that formed more than 70 years ago and is currently experiencing sedge regrowth exhibited large winter CH4 bottom flux of 59 mg CH4-C m−2 d−1, while older ponds dominated by Sphagnum mosses showed 4 to 10 times smaller CH4 bottom fluxes.

• Hellevang, Helge; Ippach, Mats Rouven; Westermann, Sebastian & Nooraiepour, Mohammad (2023). Formation of giant Siberian gas emission craters (GECs). EarthArXiv preprint platform. doi: 10.31223/X59Q3K. Full text in Research Archive Show summary

  The recent discovery of eight giant gas escape craters (GECs) in the Russian Yamal and Gydan peninsulas has challenged researchers for the past decade. Despite numerous proposed models, ranging from meteor impacts to gas explosions, none provide a comprehensive explanation for why the GECs are found only in this specific region. This study proposes a new general model for the formation of GECs in which local permafrost thinning is linked to the local geology, i.e., discrete conductive faults bring natural gas and heat to the base permafrost, deforming and melting the base leading to the development of domal gas and heat traps. Atmospheric warming results in further local thinning and eventually mechanical collapse. The morphology of the GECs initially reflects the concentric deformation above domal base-permafrost structures but are after a short time disguised by water and sediment infill, and over time peatification, and cannot be distinguished from e.g., thermokarst lakes. Thus, the true number of GECs may largely exceed those already discovered.

• Jurikova, Hana; Ippach, Mats Rouven; Liebetrau, Volker; Gutjahr, Marcus; Krause, Stefan & Büsse, Sebastian [Show all 13 contributors for this article] (2020). Incorporation of minor and trace elements into cultured brachiopods: Implications for proxy application with new insights from a biomineralisation model. Geochimica et Cosmochimica Acta. ISSN 0016-7037. 286, p. 418–440. doi: 10.1016/j.gca.2020.07.026. Full text in Research Archive

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• Carlsen, Eira Catharine Lødrup; Pismeniuk, Anfisa; Wei, Jing; Ippach, Mats Rouven; Dörsch, Peter & Westermann, Sebastian [Show all 9 contributors for this article] (2026). FROM PEAT TO PONDS: LANDSCAPE HETEROGENEITY DRIVES METABOLIC NETWORKS AND GREENHOUSE GAS RELEASE FROM THAWING PERMAFROST. Full text in Research Archive Show summary

  As permafrost landscapes degrade, they transform into a hydrological mosaic of dry palsas, collapsing thermokarst slumps, and water-saturated ponds. This physical reorganization creates steep gradients in redox potential and organic matter quality, fundamentally altering the thermodynamic constraints on microbial metabolism. We investigated greenhouse gas (CO2, CH4, N2O) production potentials across several permafrost thaw gradients in sub-Arctic peatlands of Northern Norway, linking landscape-scale changes to genome-resolved metabolic networks. By integrating high-resolution metagenomics with organic matter and greenhouse gas production characterization, we found that thaw features act as distinct thermodynamic bioreactors. In water-saturated, anoxic peat layers, oxygen limitation selects for "slow" metabolic guilds specialized in fermentation and methanogenesis while other oxygenated features are constrained by the quality of organic matter—specifically the accumulation of polyphenols and aromatic compounds acts as a metabolic "latch". We show that the shift from oxic to anoxic conditions triggers a non-linear restructuring of the microbial network, where less efficient central metabolism drives high N2O and CH4 yields but suppressed CO2 production. These findings demonstrate that predicting the permafrost-carbon feedback requires mapping the "metabolic landscape"—where organic matter quality and redox thresholds ultimately tune the greenhouse gas release from thawing landscapes to the atmosphere.

• Carlsen, Eira Catharine Lødrup; Wei, Jing; Lejzerowicz, Franck Laurent Patrick; Ippach, Mats Rouven; Pismeniuk, Anfisa & Kjær, Sigrid Trier [Show all 10 contributors for this article] (2025). Greenhouse gas production kinetics and metabolic traits in thawing permafrost peat. Full text in Research Archive Show summary

  While numerous drivers of greenhouse gas emission (GGE) have been suggested to drive variabilities across thawing landscapes, experimental validations are still widely lacking . Here, I will present results from several experimental studies capturing drivers of GGE across thawing permafrost landscapes like redox, organic matter and microbial source community. Our findings reveal clear responses of the greenhouse gases to redox conditions across the landscape. CO2 production showed a drastic decline when O2 dropped below 100 μM; specifically, under anoxic conditions, CO2 yield and maximum net production rates decreased by around 90 % compared to oxic conditions. CH4 levels remained consistent across O2 gradients, until at least 6 months upon thawing. Functional groups like N2O reducers, fermenters, denitrifiers, and sulfur reducers increased under anoxic conditions, and the reduced CO2 production rates and yields under anoxic conditions were reflected by genomic changes towards reduced central metabolic efficiency. Our data thus points towards critical GGE thresholds under suboxic conditions across thawing landscapes. Moreoever, gas dynamics seem to be primarily influenced by permafrost conditions rather than source community colonization. Our experiments provide increased knowledge on the variable GGE across thawing permaforst landscapes influenced by variable redox conditions and permafrost´s organic matter legacy.

• Sheffield, Sunniva Bratli; Vogt, Rolf David & Ippach, Mats Rouven (2025). Dissolved natural organic matter in Boreal soil waters Its sources, transport, and fate. Universitetet i Oslo. Full text in Research Archive Show summary

  Denne studien undersøker transportdynamikken til løst organisk materiale (DOM) i porevannene i myrområder ved Langtjern, et borealt økosystem i Nord-Norge. Målet var å forbedre forståelsen av hvordan hydrologiske gradienter, dynamikken i organisk materiale og biogeokjemiske kontrollmekanismer interagerer for å forme nærings- og karbonkretsløpene i disse klimafølsomme miljøene. Myrområder spiller en kritisk rolle i næringsretensjon og karbonlagring, noe som gjør dem til essensielle komponenter i konteksten av klimaendringer og økosystemresiliens. Studien undersøkte variasjonen av DOM, pH, elektrisk ledningsevne (EC), oksidasjon-reduksjon (RedOx) forhold, viktige næringsstoffer (løst nitrogen og fosfor), samt hovedkationer og -anioner på tvers av ulike torvtyper. Resultatene avslørte uttalt romlig og tidsmessig variasjon i disse parameterne, hvilket understreker kompleksiteten i de biogeokjemiske prosessene som styrer mobiliteten og distribusjonen av næringsstoffer og karbon. Funnene fremhever den sentrale rollen hydrologiske strømningsveier har i kontrollen av næringstransport og understreker behovet for å vurdere disse dynamikkene i strategier for forvaltning av myrområder, bevaring og tilpasning til klimaendringer.

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