Pedogeomorphology and paleoenvironmental implications of large termite mounds at the Brazilian semiarid landscape

Freitas, Diana Ferreira de; Ker, João Carlos; Filho, Luiz Aníbal da Silva; Pereira, Thiago Torres Costa; Souza, Og Francisco Fonseca de; Schaefer, Carlos Ernesto Gonçalves Reynaud

doi:10.1016/j.geomorph.2021.107762

Cited by 15 publications

(13 citation statements)

References 47 publications

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“…According to recent studies, the biological origin for the microgranular structure appears to be the most likely explanation [Freitas et al, 2021, Jouquet et al, 2016, Mujinya et al, 2013, Oliveira et al, 2012, Reatto et al, 2009, Sarcinelli et al, 2009. Faunal activity in latosols continuously brings material from the saprolite and deep horizons to the upper horizons, thus bringing up minerals such as the 2:1 phyllosilicates studied here to the Bw horizons.…”

Section: Origin Of the Particles Of 2:1 Phyllosilicatesmentioning

confidence: 67%

“…On the basis of the studies carried out which were essentially based on X-ray diffraction analysis, these minerals are, according to the authors, (i) either neoformed within the Bw horizons of latosols, HIVs resulting from the direct formation of 2:1 clay minerals with interlayer Al from the soil solution rich in Al [e.g. Bertolazi et al, 2017, Bortoluzzi et al, 2008, Karathanasis et al, 1983, Volkoff and Melfi, 1980, (ii) or related to bioturbation produced by termites and ants which take material from the saprolite and bring it up to the Bw horizons of latosols [Freitas et al, 2021, Schaefer, 2001. In this context, the objective of the present study was (i) to describe the microstructure of selected Bw horizons of latosols by using backscattered electron scanning images (BESI) of polished sections, (ii) to identify 2:1 minerals in the BESI of the groundmass at high magnification, (iii) to describe their morphology, (iv) and to analyze their chemical composition using energydispersive X-ray spectroscopy (EDS).…”

Section: Introductionmentioning

confidence: 99%

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Morphology, chemical composition and origin of 2:1 phyllosilicates in Bw horizons of latosols of the Brazilian Central Plateau: contribution to the discussion of the microgranular structure origin

Bruand¹,

Reatto²

2022

Comptes Rendus. Géoscience

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Polished sections of two Bw horizons collected in latosols located on the South American Surface (LSAS) and the Velhas Surface (LVS) in the Brazilian Central Plateau were studied using backscattered scanning images (BESI) in scanning electron microscopy and energy dispersive spectroscopy (EDS). BESI showed areas with a strong microgranular structure associated with areas having a weak to moderate microgranular structure. BESI at high magnification also showed the presence of

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Section: Origin Of the Particles Of 2:1 Phyllosilicatesmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Morphology, chemical composition and origin of 2:1 phyllosilicates in Bw horizons of latosols of the Brazilian Central Plateau: contribution to the discussion of the microgranular structure origin

Bruand¹,

Reatto²

2022

Comptes Rendus. Géoscience

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“…These soils are good candidates for highlighting the presence of material originating from the saprolite which usually appears usually at several meters depth, as the mineralogical composition of their ferralic B horizons is very different from that of the underlying saprolite. Moreover, they host numerous soil-feeding termite communities 7,20,[26][27][28][29][30] .…”

Section: Resultsmentioning

confidence: 99%

Allochthonous material originating from saprolite as a marker of termite activity in Ferralsols

Bruand

Reatto

Martins

2022

Sci Rep

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Ferralsols, which are estimated to cover 7.5 millions km2 worldwide, are deeply weathered red or yellow soils found in the humid tropics. They are considered as the end of a geochemical sequence of weathering and are dominated by low-activity clay and sesquioxides. Their physical properties are closely related to their strong submillimetric granular structure. We aimed to characterize the 2:1 clay minerals identified in many Ferralsols and to discuss them as a marker of soil-feeding termite activity in Ferralsols. We present results recorded with Brazilian Ferralsols developed under Cerrado native vegetation on a range of parent materials. It was found that the 2:1 minerals vary from weakly weathered muscovite to hydroxy-Al interlayered vermiculite, sometimes associated to a fine material with a chemical composition highly different from that of the groundmass of the surrounding submillimetric granular aggregates. Results show that both 2:1 minerals and the associated fine material have to be considered as allochthonous material originating from the saprolite and were brought to the Ferralsol by soil-feeding termite activity. This confirms the major role of termites in the properties of Ferralsols and raises questions about the possible consequences of land use change which usually deeply affects soil biodiversity.

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“…Mound-forming termites and large epigeal mounds are the common features of the landscape in most semiarid regions [1,2]. Termites through their pedoturbation drastically change soil properties and infuence soil genesis [3,4]. Te mechanism by which termites afect soil formation is by altering the type of soil that had formed years ago, e.g., from Alisols and Acrisols to umbric properties [4], by extracting clay-enriched materials from the subsoil, e.g., from the Kandic horizon [5] and the Argic horizon [4], by promoting soil homogenization [3], by infuencing soil formation processes [6], and by infuencing morphological properties [7].…”

Section: Introductionmentioning

confidence: 99%

“…Termites through their pedoturbation drastically change soil properties and infuence soil genesis [3,4]. Te mechanism by which termites afect soil formation is by altering the type of soil that had formed years ago, e.g., from Alisols and Acrisols to umbric properties [4], by extracting clay-enriched materials from the subsoil, e.g., from the Kandic horizon [5] and the Argic horizon [4], by promoting soil homogenization [3], by infuencing soil formation processes [6], and by infuencing morphological properties [7]. Another important impact is the tunneling and reflling of the subsoil with topsoil [8] and by modifying the mineralogical composition of the soil [9].…”

Section: Introductionmentioning

confidence: 99%

Genesis and Classification of Termite-Mediated Soils along Toposequences in a Semiarid Area of Southeast Ethiopia

Bekele

Beyene

Kiflu

et al. 2023

Applied and Environmental Soil Science

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Despite the ecosystem functioning they provide, termite pedoturbation along toposequence is overlooked in the genesis of semiarid soils. Therefore, we aimed to describe morphological and physicochemical properties that lead to the classification of termite-mediated soils. In this study, representative pedons, one on each slope class, were described and classified for five different topographical positions, and the soil properties of genetic horizons were compared to those obtained from respective mounds. The result showed that the soils were heavily manipulated by termites except for the pedon at the toe slope. Cambisols were formed on the summit and back slope and resulted from slow pedogenic processes. Luvisols on the toe slope showed redoximorphic features, and gleization and clay synthesis formed the soil, while the upward movement of coarse particles enhanced textural differentiation. Luvisols at the foot of the slope are formed by the partial destruction of iron-bearing minerals accompanied by eluviation-illuviation processes. Accumulation of calcium carbonate following calcification formed Calcisols on the bottom slope. Comparing the mounds and reference pedons, much of the mound’s soil is mined from the subsoil, usually from B horizons. However, their influence on soil properties depended mainly on the topography. Moreover, the morphological and physicochemical properties of the studied pedons exhibited various degrees of variation along topography and clearly showed topographic effects. In conclusion, termites can be a potent mediator of soil genesis across toposequences, and their activities should be considered in the classification and management of semiarid soils. A further retrospective examination of micromorphological evidence is recommended to support this finding.

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Pedogeomorphology and paleoenvironmental implications of large termite mounds at the Brazilian semiarid landscape

Cited by 15 publications

References 47 publications

Morphology, chemical composition and origin of 2:1 phyllosilicates in Bw horizons of latosols of the Brazilian Central Plateau: contribution to the discussion of the microgranular structure origin

Morphology, chemical composition and origin of 2:1 phyllosilicates in Bw horizons of latosols of the Brazilian Central Plateau: contribution to the discussion of the microgranular structure origin

Allochthonous material originating from saprolite as a marker of termite activity in Ferralsols

Genesis and Classification of Termite-Mediated Soils along Toposequences in a Semiarid Area of Southeast Ethiopia

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