Iron (hydr)oxide formation in Andosols under extreme climate conditions
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Iron (hydr)oxide formation in Andosols under extreme climate conditions. / Klaes, Björn; Thiele-Bruhn, Sören; Wörner, Gerhard; Höschen, Carmen; Mueller, Carsten W.; Marx, Philipp; Arz, Helge Wolfgang; Breuer, Sonja; Kilian, Rolf.
In: Scientific Reports, Vol. 13, 2818, 2023.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Iron (hydr)oxide formation in Andosols under extreme climate conditions
AU - Klaes, Björn
AU - Thiele-Bruhn, Sören
AU - Wörner, Gerhard
AU - Höschen, Carmen
AU - Mueller, Carsten W.
AU - Marx, Philipp
AU - Arz, Helge Wolfgang
AU - Breuer, Sonja
AU - Kilian, Rolf
N1 - © 2023. The Author(s).
PY - 2023
Y1 - 2023
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.
AB - 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.
U2 - 10.1038/s41598-023-29727-1
DO - 10.1038/s41598-023-29727-1
M3 - Journal article
C2 - 36797309
VL - 13
JO - Scientific Reports
JF - Scientific Reports
SN - 2045-2322
M1 - 2818
ER -
ID: 346074831