Grosse, Guido

Kuhry, Peter

Mauclet, Elisabeth

Monhonval, Arthur

Opfergelt, Sophie

Schirrmeister, Lutz

Strauss, Jens

English

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=Drainedthermokarstlake bassinsWe are studying the Yedoma domain regionArthur Monhonval1, Sophie Opfergelt1, Elisabeth Mauclet1, Catherine Hirst1, Jens Strauss2, Guido Grosse2, Lutz Schirrmeister2, Peter Kuhry31Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium2 Department of Periglacial Research, Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Potsdam 14473, Germany 3 Department of Physical Geography, Stockholm University, SwedenContact : arthur.monhonval@uclouvain.beYedoma are ice-rich permafrost Thermokarst: a driver for elementsreleaseWhat is the potential impact of mineral elements release on organic carbon?Yedoma cliff in Sobo Sise (Siberia)(Photo by J. Strauss)Alas exposure in Baldwin peninsula (Alaska) (Photo by J. Strauss)ThermokarstprocessesContain 1/3 of the global permafrost organic C stockAre highly sensitive to thaw with warmingclimateExpose deep organicmatter (OM) and mineralconstituentsUnlock interactions between OM and mineralsYedoma AlasMineral elements assessmentis needed in Yedoma regionsbecause of their influence on organic carbon dynamicsYedomaAlasSource : [1]Frozen stateCO2CO2CO2CH4CH4CH4- Organic carbon stabilization (complex formation Fe3+, Al3+, Ca2+)- Supply of limiting micronutrients for microbial growth (Fe, Mn,..)- Possible inhibition effect on CO2 and CH4 emissionsFe pXRF [mg/kg]Fe ICP-AES [mg/kg]CaR² = 0.983Ca pXRF [mg/kg]Ca ICP-AES [mg/kg]ThermokarstprocessesYEDOMA (n=850) ALAS (n=503) Ca pXRF [mg/kg]Density• Portable X-Ray Fluorescence device (pXRF) : fast and cheap alternative method to assess mineral element content (R² > 0.6 for Fe, Ca, Si, K, Ti, Zn, Sr and Zr). Take home messages• What is the proportion of Fe oxides and amorphous Fe oxides in Yedoma and Alasdeposits?Fe total Amorphous Fe in Fe oxidesCrystalline Fe in Fe oxides• Fast method (pXRF) to assess mineral element content in permafrost samples Fe, Ca, Si, K, Ti, Zn, Zr and Sr.  • Changes in total content in Ca, Al and Fe between Yedoma and Alas deposits.• Thermokarst disturbances affect mineral element distribution and might affect the mineralelements availability to form associations with organic carbon. [1] modified from Walter Anthony et al., 2014, Nature.[2] Lipson et al., 2012, Biogeosci., 9, 577–591.[3] Baek et al., 2019, Ren. Sus. Energy Rev. 113, 109282.[4] Schwertmann et al., 1977, Soil Sci. Soc. Am.Fe oxides in Fe totalFe primary minerals in Fe totalCitrate-bicarbonate-dithionateextractions (DCB)Oxalate extractionspXRFSampling locationsThanks to Anne Iserentant, Claudine Givron and Hélène Dailly for the technical help and to Nathan Bemelmans for labwork.Thank you to Benoit Pereira and Aubry Vandeuren for pXRF technical support. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N°714617.Subsidence and lake formationLake drainageRefrozendrainedthermokarstlake bassin (DTLB)Assessing mineral element content on a global scaleDecrease in soluble mineral elements such as Ca upon thermokarst processesFeR² = 0.807n=144Allow a fast screening of mineral elements withinYedoma and Alas depositsTime consumingstandard methodpXRFSiberia AlasSiberia YedomaYedoma and Alas deposits contain Fe oxides : role for organic carbon051015202530020406080100051015202530020406080100Fe oxidesin Fe total (%)AmorphousFe in Fe oxides(%)AlasYedomaSoboSiseKytalyk Buor Khaya SoboSiseKytalyk BuorKhaya• Yedoma and Alas deposits contain 25% (average) of Fe oxides of which 81% are amorphous or readily dissociated. • Distinction between Yedoma and Alas requires to compare more sites at comparable distances. Fe oxidesAggregationAdsorptionMethanogenesis inhibition [2](larger role of amorphous Fe oxides)[3,4]+ water-soluble organic moleculesAlaska AlasAlaska YedomaFast alternative methodContinuous permafrost (90-100%)Isolated permafrost (0-10%)Sporadic permafrost (10-50%)Disontinuous permafrost (50-90%)Glaciers

Influence of Holocene thermokarst activities on mineral element content in Yedoma deposits

https://epic.awi.de/id/eprint/53070/1/Monhonval_Arctic_week_poster.pdf

Influence of Holocene thermokarst activities on mineral element content in Yedoma deposits

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