TY - JOUR

T1 - Cryoturbation impacts iron-organic carbon associations along a permafrost soil chronosequence in northern Alaska

AU - Joss, Hanna

AU - Patzner, Monique S.

AU - Maisch, Markus

AU - Mueller, Carsten W.

AU - Kappler, Andreas

AU - Bryce, Casey

N1 - Funding Information: We thank Jenny Kao-Kniffin, James Bockheim and Kenneth Hinkel for the invitation to join the 2010 expedition, the joint work in the field and all logistic assistance. We are grateful for assistance in field work and sampling by Christine Mlot and the Barrow Arctic Science Consortium (BASC). The funding for the sampling campaign was provided by the NSF Postdoctoral Fellowship in Polar Regions Research (#0852036). We thank Marie Greiner and Miroslava Malusova for assistance in the lab, Ellen R?hm for OC measurements and Johannes Lugmeier for NanoSIMS measurements. We are grateful for the financial support from the German Science Foundation (DFG) in the frame of the ?Initiation of International Collaboration? program (MU 3021/2-1), for support from the German Academic Scholar Foundation (scholarship to M.P) and for support through the ?Programme for the Promotion of Junior Researchers? award to C.B from the University of T?bingen. The authors further acknowledge infrastructural support by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy, cluster of Excellence EXC2124, project ID 390838134. Funding Information: We thank Jenny Kao-Kniffin, James Bockheim and Kenneth Hinkel for the invitation to join the 2010 expedition, the joint work in the field and all logistic assistance. We are grateful for assistance in field work and sampling by Christine Mlot and the Barrow Arctic Science Consortium (BASC). The funding for the sampling campaign was provided by the NSF Postdoctoral Fellowship in Polar Regions Research (#0852036). We thank Marie Greiner and Miroslava Malusova for assistance in the lab, Ellen Röhm for OC measurements and Johannes Lugmeier for NanoSIMS measurements. We are grateful for the financial support from the German Science Foundation (DFG) in the frame of the “Initiation of International Collaboration” program (MU 3021/2-1), for support from the German Academic Scholar Foundation (scholarship to M.P) and for support through the “Programme for the Promotion of Junior Researchers” award to C.B from the University of Tübingen. The authors further acknowledge infrastructural support by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy, cluster of Excellence EXC2124, project ID 390838134. Publisher Copyright: © 2022 Elsevier B.V.

PY - 2022/5/1

Y1 - 2022/5/1

N2 - In permafrost soils, substantial amounts of organic carbon (OC) are potentially protected from microbial degradation and transformation into greenhouse gases by association with reactive iron (Fe) minerals. As permafrost environments respond to climate change, increased drainage of thaw lakes in permafrost regions is predicted. Soils will subsequently develop on these drained thaw lakes, but the role of Fe-OC associations in future OC stabilization during this predicted soil development is unknown. To fill this knowledge gap, we have examined Fe-OC associations in organic, cryoturbated and mineral horizons along a 5500-year chronosequence of drained thaw lake basins in Utqiaġvik, Alaska. By applying chemical extractions, we found that ∼17% of the total OC content in cryoturbated horizons is associated with reactive Fe minerals, compared to ∼10% in organic or mineral horizons. As soil development advances, the total stocks of Fe-associated OC more than double within the first 50 years after thaw lake drainage, because of increased storage of Fe-associated OC in cryoturbated horizons (from 8 to 75% of the total Fe-associated OC stock). Spatially-resolved nanoscale secondary ion mass spectrometry showed that OC is primarily associated with Fe(III) (oxyhydr)oxides which were identified by 57Fe Mössbauer spectroscopy as ferrihydrite. High OC:Fe mass ratios (>0.22) indicate that Fe-OC associations are formed via co-precipitation, chelation and aggregation. These results demonstrate that, given the proposed enhanced drainage of thaw lakes under climate change, OC is increasingly incorporated and stabilized by the association with reactive Fe minerals as a result of soil formation and increased cryoturbation.

AB - In permafrost soils, substantial amounts of organic carbon (OC) are potentially protected from microbial degradation and transformation into greenhouse gases by association with reactive iron (Fe) minerals. As permafrost environments respond to climate change, increased drainage of thaw lakes in permafrost regions is predicted. Soils will subsequently develop on these drained thaw lakes, but the role of Fe-OC associations in future OC stabilization during this predicted soil development is unknown. To fill this knowledge gap, we have examined Fe-OC associations in organic, cryoturbated and mineral horizons along a 5500-year chronosequence of drained thaw lake basins in Utqiaġvik, Alaska. By applying chemical extractions, we found that ∼17% of the total OC content in cryoturbated horizons is associated with reactive Fe minerals, compared to ∼10% in organic or mineral horizons. As soil development advances, the total stocks of Fe-associated OC more than double within the first 50 years after thaw lake drainage, because of increased storage of Fe-associated OC in cryoturbated horizons (from 8 to 75% of the total Fe-associated OC stock). Spatially-resolved nanoscale secondary ion mass spectrometry showed that OC is primarily associated with Fe(III) (oxyhydr)oxides which were identified by 57Fe Mössbauer spectroscopy as ferrihydrite. High OC:Fe mass ratios (>0.22) indicate that Fe-OC associations are formed via co-precipitation, chelation and aggregation. These results demonstrate that, given the proposed enhanced drainage of thaw lakes under climate change, OC is increasingly incorporated and stabilized by the association with reactive Fe minerals as a result of soil formation and increased cryoturbation.

KW - Carbon

KW - Drained thaw lake basin

KW - Iron

KW - Permafrost

KW - Soil organic matter

KW - Thermokarst

U2 - 10.1016/j.geoderma.2022.115738

DO - 10.1016/j.geoderma.2022.115738

M3 - Journal article

AN - SCOPUS:85123988079

VL - 413

JO - Geoderma

JF - Geoderma

SN - 0016-7061

M1 - 115738

ER -