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

Autor(es)

Sartor, Lucas Resmini ^[1] ; Graham, Robert C. ^[2] ; Ying, Samantha C. ^[2] ; Luis Otero, Xose ^[3] ; Montes, Celia Regina ^[4] ; Ferreira, Tiago Osorio ^[5]

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: Soil Science Society of America Journal; v. 82, n. 5, p. 1217-1230, SEP-OCT 2018.
• Citações Web of Science: 1

Resumo

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)

• Processo FAPESP: 16/09024-8 - Modelagem de raios-X e técnicas de microscopia eletrônica aplicadas ao estudo de minerais em solos hipersalinos
• Beneficiário: Lucas Resmini Sartor
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado
• Processo FAPESP: 16/21026-6 - Solos de áreas úmidas da costa brasileira (planícies hipersalinas e pradarias marinhas): pedogênese e biogeoquímica do Fe, Si e C
• Beneficiário: Tiago Osório Ferreira
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 14/11776-2 - Caracterização do meio físico, geoquímica de Fe e s e dinâmica de alteração de minerais em solos de planícies hipersalinas da costa brasileira
• Beneficiário: Lucas Resmini Sartor
• Modalidade de apoio: Bolsas no Brasil - Doutorado