Chemical weathering in the volcanic soils of Isla Santa Cruz (Galápagos Islands, Ecuador)

Rodríguez, Teresa Taboada; Rodríguez‐Lado, Luis; Ferro-Vázquez, Cruz; Stoops, Georges; Cortizas, Antonio Martínez

doi:10.1016/j.geoderma.2015.07.019

Cited by 39 publications

(21 citation statements)

References 44 publications

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“…The decrease in total Si and the consequent residual accumulation of total Al and Fe with altitude (Figure ) are consistent with the loss of Si with weathering and the removal of basic cations typical of volcanic soils (Arnalds et al, ; Rasmussen et al, ). This has been discussed in detail by Taboada et al () in terms of a greater degree of weathering because of the wetter climate at higher altitudes.…”

Section: Discussionmentioning

confidence: 92%

“…Figure shows the locations studied and a brief description of each soil is included in the Supporting Information (Table S1). Further detail can be found in Eswaran et al (), Rodríguez Flores et al (), Stoops (, ), Taboada et al () and Rial et al ().…”

Section: Methodsmentioning

confidence: 99%

“…Further detail can be found in Eswaran et al (1973), Rodríguez Flores et al (2006), Stoops (2013Stoops ( , 2014, Taboada et al (2016) and Rial et al (2017).…”

Section: Soil Samplingmentioning

confidence: 97%

“…The free Si (Sin), however, increased only in the less weathered soils from lower altitudes (those from the AZ and TZ, according to Taboada et al, 2016), and remained unchanged at higher altitudes because of the partial depletion of Si by leaching. As a result, the amount of free Al compared to Sin (Aln/Sin) increased with altitude ( Figure 5).…”

Section: Trends With Altitudementioning

confidence: 99%

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Secondary aluminium, iron and silica phases across a volcanic soil climosequence, Galápagos Islands

Rodríguez

Ferro-Vázquez

Stoops

et al. 2019

European J Soil Science

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We applied selective dissolution extractions (Na‐pyrophosphate, acid oxalate, cold NaOH and citrate‐dithionite) to study Al, Fe and Si fractionation in 38 volcanic pedons located on the windward slopes of Santa Cruz (Galápagos Islands) that form a climosequence. The aim was to evaluate the distribution of secondary Fe, Al and Si phases in relation to environmental variables. Two main trends were observed: a geographical pattern in relation to altitude and a vertical differentiation within soil profiles. Soils from the drier coastal area had the smallest amounts of secondary Al, Fe and Si, whereas values were larger in soils at higher altitude, under a more humid climate. Organo–metallic complexes dominate the organic‐rich topsoils in these wetter areas as a result of larger availability of free Al, more humified organic matter with a greater capacity for metal adsorption and larger organic matter contributions from vegetation. This has led to increased accumulation of organic carbon in soils at higher altitudes. At lower elevations, inorganic secondary materials are more frequent, with short‐range‐order minerals prevailing in topsoils, whereas crystalline minerals dominate subsoils. Crystalline minerals are also frequent in some soils at higher altitudes in relation to acid pH. Vertical differentiation within the soil profile is also responsive to altitude: differences between topsoils and subsoils are generally more marked in soils at higher locations, thus wetter areas. A greater degree of weathering seems to be the main factor controlling both altitudinal trends and horizonation through its effect on pH, organic matter content and humification, ultimately controlled by climatic variation. Highlights We analysed soils developed on volcanic material along the windward slope of Santa Cruz Island. Organo–metallic complexes are abundant in acidic, organic‐rich epipedons at higher elevation. Short‐range‐order minerals are more abundant in non‐acidic subsoils and tend to increase with altitude Crystalline minerals predominate at lower elevation and in acidic subsoils at higher altitude.

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Section: Discussionmentioning

confidence: 92%

Section: Methodsmentioning

confidence: 99%

“…Further detail can be found in Eswaran et al (1973), Rodríguez Flores et al (2006), Stoops (2013Stoops ( , 2014, Taboada et al (2016) and Rial et al (2017).…”

Section: Soil Samplingmentioning

confidence: 97%

Section: Trends With Altitudementioning

confidence: 99%

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Secondary aluminium, iron and silica phases across a volcanic soil climosequence, Galápagos Islands

Rodríguez

Ferro-Vázquez

Stoops

et al. 2019

European J Soil Science

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“…These low levels result from chemical weathering leading to the dissolution of silica (see Alexander et al, 1954;Xu, 2009;Taboada et al, 2016) allowing Si in solution to leach out from the soil profile.…”

Section: Soil Geochemistrymentioning

confidence: 99%

Geoarchaeological evidence for the construction, irrigation, cultivation, and resilience of 15^th--18^th century AD terraced landscape at Engaruka, Tanzania

Lang

Stump

2017

Quat. res.

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Agricultural landscapes are human-manipulated landscapes, most obviously in areas modified by terracing and/or irrigation. Examples from temperate, arid, and desert environments worldwide have attracted the attention of many disciplines, from archaeologists, palaeoecologists, and geomorphologists researching landscape histories to economists, agronomists, ecologists, and development planners studying sustainable resource management. This article combines these interdisciplinary interests by exploring the role archaeology can play in assessing sustainability. Our case study is Engaruka, Tanzania, archaeologically famous as the largest abandoned irrigated and terraced landscape in East Africa. The site has been cited as an example of economic and/or ecological collapse, and it has long been assumed to have been irrigated out of necessity because agriculture was presumed to be nearly impossible without irrigation in what is now a semiarid environment. Geoarchaeological research refutes this assumption, however, demonstrating that parts of the site flooded with sufficient regularity to allow the construction of more than 1000 ha of alluvial sediment traps, in places greater than 2 m deep. Soil micromorphology and geochemistry also record changes in irrigation, with some fields inundated to create paddylike soils. Geoarchaeological techniques can be applied to both extant and abandoned agricultural systems, thereby contributing to an understanding of their history, function, and sustainability.

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Cadmium retention and microbial response in volcanic soils along gradients of soil age and climate on the Galápagos Islands

et al. 2021

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The behavior of trace metals may vary strongly in the course of volcanic soil development. Cadmium retention in soils is specifically important for some Galápagos islands where agriculture is leading to anthropogenic Cd contamination. To assess the influence of soil development factors on soil Cd retention and toxicity, we performed Cd sorption-desorption experiments with volcanic topsoils from the Galápagos Islands sampled along gradients of (a) substrate age (chronosequence, 1.5-1,070 ka) and (b) climate (elevation sequence, 47-866 m asl) ranging from arid lowland areas to humid highland areas. Additionally, the effects of Cd toxicity on the soil microbial community composition were evaluated for two soils of the chronosequence. In young volcanic soils, the sorption capacity was very high but decreased rapidly with soil age and increasing elevation. These trends were coupled with decreases in soil weathering indicators (e.g., electrical conductivity, pH, and effective cation exchange capacity) as well as changes in soil mineralogy. Cadmium addition did not influence total phospholipid fatty acids and basal respiration in most soils. However, with increasing Cd concentration, a pronounced reduction in the Gram-negative/Gram-positive bacteria ratio (from 0.32 to 0.12) occurred in an old, highly weathered soil with low Cd retention capacity. Our results show that up to 60% of added Cd was only weakly sorbed in old volcanic soils. As a consequence, the old volcanic soils of Galápagos bear the potential risk that the mobile Cd fraction is taken up by soil microorganisms, transferring this element into the food chain.

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Chemical weathering in the volcanic soils of Isla Santa Cruz (Galápagos Islands, Ecuador)

Cited by 39 publications

References 44 publications

Secondary aluminium, iron and silica phases across a volcanic soil climosequence, Galápagos Islands

Secondary aluminium, iron and silica phases across a volcanic soil climosequence, Galápagos Islands

Geoarchaeological evidence for the construction, irrigation, cultivation, and resilience of 15^th--18^th century AD terraced landscape at Engaruka, Tanzania

Cadmium retention and microbial response in volcanic soils along gradients of soil age and climate on the Galápagos Islands

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Chemical weathering in the volcanic soils of Isla Santa Cruz (Galápagos Islands, Ecuador)

Cited by 39 publications

References 44 publications

Secondary aluminium, iron and silica phases across a volcanic soil climosequence, Galápagos Islands

Secondary aluminium, iron and silica phases across a volcanic soil climosequence, Galápagos Islands

Geoarchaeological evidence for the construction, irrigation, cultivation, and resilience of 15th--18th century AD terraced landscape at Engaruka, Tanzania

Cadmium retention and microbial response in volcanic soils along gradients of soil age and climate on the Galápagos Islands

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Geoarchaeological evidence for the construction, irrigation, cultivation, and resilience of 15^th--18^th century AD terraced landscape at Engaruka, Tanzania