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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Role of Redox Processes in the Pedogenesis of Hypersaline Tidal Flat Soils on the Brazilian Coast

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Sartor, Lucas Resmini [1] ; Graham, Robert C. [2] ; Ying, Samantha C. [2] ; Luis Otero, Xose [3] ; Montes, Celia Regina [4] ; Ferreira, Tiago Osorio [5]
Total Authors: 6
[1] Univ Fed Sergipe, Dept Agron, Campus Sertao, BR-49680000 Nossa Senhora Da Gloria, Sergipe - Brazil
[2] Univ Calif Riverside, Dept Environm Sci, Soil & Water Sci Program, Riverside, CA 92521 - USA
[3] Univ Santiago de Compostela, Fac Biol, Dept Edafol & Quim Agr, Santiago De Compostela 15782 - Spain
[4] Univ Sao Paulo, Ctr Nucl Energy Agr, BR-13416000 Piracicaba, SP - Brazil
[5] Univ Sao Paulo, Luiz de Queiroz Coll Agr, Soil Sci Dept, BR-13418900 Piracicaba, SP - Brazil
Total Affiliations: 5
Document type: Journal article
Source: Soil Science Society of America Journal; v. 82, n. 5, p. 1217-1230, SEP-OCT 2018.
Web of Science Citations: 1

Hypersaline tidal flats (HTFs) represent transitional ecosystems where the ocean, land, and freshwater meet. These places are globally widespread and their soils are an important environmental component controlling chemical reactions in wetland ecosystems. Here, we present a pedogenic study of two HTFs on the Brazilian coast (northeast and southeast) based on the solid-phase geochemistry of Fe and Mn and morphological studies. Broken and irregular topographies and strong expression of redoximorphic concentrations (e.g., mottles, nodules, and pore linings) are present throughout the soil profiles. Although lepidocrocite is the most abundant Fe fraction in these soils (more than 50% of all extractions), deeper horizons show pyrite as the main Fe fraction caused by the presence of buried mangrove soils. The more oxidizing conditions in these deeper horizons indicate that pyrite is not stable and is undergoing degradation. Iron released in this process is moving upward and precipitating as Fe oxides in more oxidized portions of the soil profile. Coprecipitation of Mn and ferrihydrite seems to be an important process controlling the geochemistry of Mn in HTFs. Our data indicate that deeper horizons have been transforming, driven mainly by water table oscillation and, consequently, redox processes. This process allows translocation of Mn2+ and Fe2+ throughout the soil profile, followed by oxidation and precipitation of Mn3+/4+ and Fe3+ oxides in preferential sites. (AU)

FAPESP's process: 16/09024-8 - X-ray diffraction modeling and electron microscopy techniques applied to the study of minerals in hypersaline soils
Grantee:Lucas Resmini Sartor
Support Opportunities: Scholarships abroad - Research Internship - Doctorate
FAPESP's process: 16/21026-6 - Brazilian coastal wetland soils (hypersaline tidal flats and seagrasses): soil genesis and biogeochemistry of Fe, Si and C
Grantee:Tiago Osório Ferreira
Support Opportunities: Regular Research Grants
FAPESP's process: 14/11776-2 - Characterization of the physical environment, geochemistry of Fe and s and dynamics of mineral alteration on hypersaline tidal flats of Brazilian coastline
Grantee:Lucas Resmini Sartor
Support Opportunities: Scholarships in Brazil - Doctorate