TY - JOUR

T1 - Porosity and organic matter distribution in jarositic phyto tubules of sulfuric soils assessed by combined µCT and NanoSIMS analysis

AU - Pohl, Lydia

AU - Kölbl, Angelika

AU - Uteau, Daniel

AU - Peth, Stephan

AU - Häusler, Werner

AU - Mosley, Luke

AU - Marschner, Petra

AU - Fitzpatrick, Rob

AU - Kögel-Knabner, Ingrid

N1 - Funding information: We would like to thank Carsten W. Mueller for ideas and discussion during the developing of the experimental design. We thank Tan Dang for support during the sample collection and Austin Trueman for the photos of the jarositic phyto tubules. Gabi Albert, Carmen Höschen and Gertraut Harrington are gratefully acknowledged for lab analyses, sample preparation and NanoSIMS measurements. Further, we thank Karin Eusterhues for support with the EDX-SEM measurements and Friedrich Wagner for conducting the Mössbauer analysis. The study was funded by the Deutsche Forschungsgemeinschaft (DFG) in the frame of the research project “Organic matter in acid sulfate soils: composition, storage and availability” (KO 2245/3-1), supported through the TUM International Graduate School of Science and Engineering (IGSSE) and partly funded by the Australian Commonwealth Government through an Australian Research Council Discovery Project Grant (DP170104541). Two anonymous reviewers are gratefully acknowledged for their comments and suggestions which considerably improved the manuscript. We would like to thank Carsten W. Mueller for ideas and discussion during the developing of the experimental design. We thank Tan Dang for support during the sample collection and Austin Trueman for the photos of the jarositic phyto tubules. Gabi Albert, Carmen H?schen and Gertraut Harrington are gratefully acknowledged for lab analyses, sample preparation and NanoSIMS measurements. Further, we thank Karin Eusterhues for support with the EDX-SEM measurements and Friedrich Wagner for conducting the M?ssbauer analysis. The study was funded by the Deutsche Forschungsgemeinschaft (DFG) in the frame of the research project ?Organic matter in acid sulfate soils: composition, storage and availability? (KO 2245/3-1), supported through the TUM International Graduate School of Science and Engineering (IGSSE) and partly funded by the Australian Commonwealth Government through an Australian Research Council Discovery Project Grant (DP170104541). Two anonymous reviewers are gratefully acknowledged for their comments and suggestions which considerably improved the manuscript.

PY - 2021/10/1

Y1 - 2021/10/1

N2 - Acid sulfate soils contain hypersulfidic material, e.g. pyrite (FeS2). Under oxidizing conditions, it transforms to sulfuric material (pH < 4), which is accompanied with the formation of jarosite [KFe3(SO4)2(OH)6] along root channels (designated as jarositic phyto tubules). The encapsulation of root residues with jarosite can lead to reduced spatial availability of organic carbon which is necessary as substrate for microbes. This can limit microbial activity which might be crucial for prospective remediation success. We investigated jarositic phyto tubules by combining X-ray computed microtomography (µCT) and nanoscale secondary ion mass spectrometry (NanoSIMS), to elucidate the porosity and organic matter distribution at the spatial scale most relevant for microbial processes. We demonstrated that the jarosite can be differentiated into zones with either high or low jarosite concentrations at distances of < 0.5 mm and 0.5–1.9 mm from the relict root channel, respectively. The results showed a closer association between jarosite and organic matter in the zone with high jarosite concentration. However, the pore space in immediate vicinity of the root is almost completely filled by jarosite and the organic matter is completely encapsulated. We conclude that the overall poor accessibility of organic matter will strongly retard remediation processes of sulfuric soils after re-submergence.

AB - Acid sulfate soils contain hypersulfidic material, e.g. pyrite (FeS2). Under oxidizing conditions, it transforms to sulfuric material (pH < 4), which is accompanied with the formation of jarosite [KFe3(SO4)2(OH)6] along root channels (designated as jarositic phyto tubules). The encapsulation of root residues with jarosite can lead to reduced spatial availability of organic carbon which is necessary as substrate for microbes. This can limit microbial activity which might be crucial for prospective remediation success. We investigated jarositic phyto tubules by combining X-ray computed microtomography (µCT) and nanoscale secondary ion mass spectrometry (NanoSIMS), to elucidate the porosity and organic matter distribution at the spatial scale most relevant for microbial processes. We demonstrated that the jarosite can be differentiated into zones with either high or low jarosite concentrations at distances of < 0.5 mm and 0.5–1.9 mm from the relict root channel, respectively. The results showed a closer association between jarosite and organic matter in the zone with high jarosite concentration. However, the pore space in immediate vicinity of the root is almost completely filled by jarosite and the organic matter is completely encapsulated. We conclude that the overall poor accessibility of organic matter will strongly retard remediation processes of sulfuric soils after re-submergence.

KW - Acid sulfate soil

KW - Iron sulfate

KW - Jarosite

KW - Mangrove roots

KW - Pore size distribution

KW - Wetlands

UR - http://www.scopus.com/inward/record.url?scp=85104128577&partnerID=8YFLogxK

U2 - 10.1016/j.geoderma.2021.115124

DO - 10.1016/j.geoderma.2021.115124

M3 - Article

AN - SCOPUS:85104128577

VL - 399

JO - GEODERMA

JF - GEODERMA

SN - 0016-7061

M1 - 115124

ER -