TY  - JOUR
A1  - Klaes, Björn
A1  - Thiele-Bruhn, Sören
A1  - Wörner, Gerhard
A1  - Höschen, Carmen
A1  - Carsten W., Mueller
A1  - Marx, Philipp
A1  - Arz, Helge Wolfgang
A1  - Breuer, Sonja
A1  - Kilian, Rolf
T1  - Iron (hydr)oxide formation in Andosols under extreme climate conditions
T2  - Scientific Reports
N2  - Redox-driven biogeochemical cycling of iron plays an integral role in the complex process network of ecosystems, such as carbon cycling, the fate of nutrients and greenhouse gas emissions. We investigate Fe-(hydr)oxide (trans)formation pathways from rhyolitic tephra in acidic topsoils of South Patagonian Andosols to evaluate the ecological relevance of terrestrial iron cycling for this sensitive fjord ecosystem. Using bulk geochemical analyses combined with micrometer-scale-measurements on individual soil aggregates and tephra pumice, we document biotic and abiotic pathways of Fe released from the glassy tephra matrix and titanomagnetite phenocrysts. During successive redox cycles that are controlled by frequent hydrological perturbations under hyper-humid climate, (trans)formations of ferrihydrite-organic matter coprecipitates, maghemite and hematite are closely linked to tephra weathering and organic matter turnover. These Fe-(hydr)oxides nucleate after glass dissolution and complexation with organic ligands, through maghemitization or dissolution-(re)crystallization processes from metastable precursors. Ultimately, hematite represents the most thermodynamically stable Fe-(hydr)oxide formed under these conditions and physically accumulates at redox interfaces, whereas the ferrihydrite coprecipitates represent a so far underappreciated terrestrial source of bio-available iron for fjord bioproductivity. The insights into Fe-(hydr)oxide (trans)formation in Andosols have implications for a better understanding of biogeochemical cycling of iron in this unique Patagonian fjord ecosystem.
KW  - Patagonien Süd
KW  - Andosol
KW  - Eisenoxide
KW  - Eisenhydroxide
KW  - Biogeochemie
Y1  - 2023
UR  - https://ubt.opus.hbz-nrw.de/frontdoor/index/index/docId/2101
UR  - https://nbn-resolving.org/urn:nbn:de:hbz:385-1-21013
VL  - 2023
IS  - Band 13
PB  - Nature Portfolio
CY  - London
ER  -