The mangrove reactor: Fast clay transformation and potassium sink

Author(s)

Cuadros, Javier ; Andrade, Gabriel ; Ferreira, Tiago Osorio ; de Moya Partiti, Carmen Silvia ; Cohen, Renato ; Vidal-Torrado, Pablo

• Document type: Journal article
• Source: APPLIED CLAY SCIENCE; v. 140, p. 50-58, MAY 2017.
• Web of Science Citations: 11

Abstract

Most known clay mineral reactions are slow. Clay formation by weathering is recognized as faster (hundreds of thousands to few million years) than clay reverse weathering (few to tens My), even if the latter takes place in deep diagenetic conditions at temperatures above 100 degrees C. Identifying hot spots of fast clay retrograde reactions acting as effective potassium sinks would contribute to eliminating the present imbalance of the potassium budget towards release into the oceans. We have identified and modeled the reaction kaolinite + Fe + cations -> Feillite occurring in Brazilian mangroves, which takes place through kaolinite-smectite and illite-smectite intermediates. The reaction is very fast, transforming 72-154 g m(-2) y(-1) of kaolinite into Fe-illite, or 16-38% of the newly sedimented kaolinite each year. This kaolinite-to-illite transformation is 10s-100s times faster than kaolinite formation by weathering. Extrapolation of the calculated potassium consumption to mangrove forests worldwide produces 0.6-3 x 10(12) g y(-1), or 1-6% of the yearly potassium riverine input into the oceans. (C) 2017 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 09/51453-0 - Mineralogy of mangrove soils of Brazilian coast
• Grantee: Pablo Vidal Torrado
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/17571-0 - XRD modeling and peak decomposition procedures applied to the study of clay minerals in Brazilian mangrove soils
• Grantee: Gabriel Ramatis Pugliese Andrade
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 11/13924-0 - Genesis and characterization of clay minerals from mangrove soils of Brazilian coast
• Grantee: Gabriel Ramatis Pugliese Andrade
• Support Opportunities: Scholarships in Brazil - Doctorate