itho-climatic characteristics and its control over mangrove soil geochemistry: A macro-scale approac

Author(s)

Ferreira, Tiago Osorio ^[1] ; Queiroz, Hermano Melo ^[1] ; Nobrega, Gabriel Nuto ^[2] ; de Souza Junior, Valdomiro S. ^[3] ; Barcellos, Diego ^{[1, 4]} ; Ferreira, Amanda Duim ^[1] ; Otero, Xose L. ^[5]

Affiliation

^[1] Univ Sao Paulo ESALQ USP, Luiz de Queiroz Coll Agr, Av Padua Dias 11, BR-13418900 Piracicaba, SP - Brazil

^[2] Fed Fluminense Univ, Dept Geochem, Grad Program Earth Sci Geochem, BR-24020140 Niteroi, RJ - Brazil

^[3] Univ Fed Rural Pernambuco, Dept Agron, Av Dom Manoel Medeiros S-N, BR-52171900 Recife, PE - Brazil

^[4] Fed Univ Sao Paulo UNIFESP, Dept Environm Sci, Rua Sao Nicolau 210, BR-09913030 Diadema, SP - Brazil

^[5] Univ Santiago de Compostela, Dept Edaphol & Agr Chem, CRETUS Inst, Fac Biol, Campus Sur, Santiago De Compostela 15782 - Spain

• Document type: Journal article
• Source: Science of The Total Environment; v. 811, MAR 10 2022.
• Web of Science Citations: 0

Abstract

Brazil hosts an extensive coastal area, marked by a great diversity of geoenvironments. The present study evaluated the role of geoclimatic factors in the geochemistry of mangrove soils by using wet extractions and several physical and chemical parameters. Soil samples were collected in 11 mangrove forests from NE (n = 94) and SE Brazil (n = 230). Our results show an important effect of the surrounding geology and climate on the geochemistry of the mangrove soils. NE mangroves are dominated by suboxic soils (mean: Eh of +150 +/- 174 mV and pH 7.1 +/- 0.5, respectively) while anoxic conditions prevail in the SE mangrove soils (mean: Eh -46 +/- 251 mV and pH 6.5 +/- 0.5). In the NE region, a period of several months without rainfall and high temperatures leads to soil suboxic conditions. Conversely, at the SE coast, the surrounding mountain range contributes to well-distributed rain favoring anoxic conditions. The contrasting geochemical environment caused differences in the geochemistry of elements such as C, Fe, and S. Significantly higher Fe (193 +/- 24 mu mol g(-1)) and organic carbon contents (6.9 +/- 7.1%) were recorded in the SE coast. The higher organic carbon contents are possibly related to Fe organo-mineral associations. These differences are ultimately associated with the contrasting geological surroundings (crystalline massifs at the SE and the iron poor sedimentary formations at the NE). The higher contents of reactive Fe and organic carbon also triggered more intense pyritization in the SE mangroves (pyritic Fe: 93 +/- 63 mu mol g(-1)). Our results demonstrate that climate and geological surroundings create identifiable patterns at a regional level and, thus, studies should take these factors into account on future global modelling approaches. (AU)

• FAPESP's process: 21/00221-3 - From sinks to sources: vulnerability of mangrove soils as carbon sinks in the face of global climate change
• Grantee: Hermano Melo Queiroz
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 19/14800-5 - Estuarine plants and their control in metals biogeochemistry in soils impacted by the `Mariana disaster´
• Grantee: Amanda Duim Ferreira
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 19/02855-0 - Redox fluctuations, iron and heavy metals dynamics in soils from Rio Doce estuary after the "Mariana (MG) disaster": an experimental approach
• Grantee: Diego Barcellos
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 19/19987-6 - Soils and plants of the Rio Doce estuary controlling the biogeochemistry of iron and metals in response to the Mariana (MG) disaster
• Grantee: Tiago Osório Ferreira
• Support Opportunities: Regular Research Grants