Marine geology, oceanography and climate

Marchant, Margarita; Cecioni, Adriano; Figueroa, Sylvia; González, Humberto; Giglio, Susana; Hebbeln, Dierk; Kaiser, Jérôme; Lamy, Frank; Mohtadi, Mahyar; Pineda, Verónica; Romero, Oscar E

doi:10.1144/goch.11

Cited by 10 publications

(18 citation statements)

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“…The continental shelf north of 33°S is narrow, rarely exceeding a width of more than 5 km (Marchant et al, 2007). The shelf edge to the deep-sea trench is situated at a depth of −120 to −150 m. Therefore, during the LGM, a great part of the shelf was probably exposed to winds, due to global sea level lowering.…”

Section: Discussionmentioning

confidence: 99%

“…For now, when looking to the periodicity of the palaeosols, missing paleosols in the profiles does not seem to be a very probable explanation. Secondly, the interpretation of Stuut and Lamy (2004) and Marchant et al (2007) is mainly based on grain size variations in the marine sediments, allowing for the differentiation of aeolian dust (coarse, dry) and fluvial mud (fine, humid). Nevertheless, it should be considered that river discharge around their coring site at 27°S is today clearly dominant during austral summer (Gobierno de Chile, 2004;Houston, 2006).…”

Section: Discussionmentioning

confidence: 99%

“…They regulate meridional heat flux and likely also the concentration of atmospheric carbon dioxide (Marchant et al, 2007;Rojas et al, 2009;Hodgson and Sime, 2010;Moreno et al, 2010). Little is known about the variability of these systems over longer time scales, and this topic has led to controversial discussions over the past decades (e.g., Kohfeld et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

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The Southern Westerlies in Central Chile during the two last glacial cycles as documented by coastal aeolian sand deposits and intercalating palaeosols

Veit

Preusser

Trauerstein

2015

CATENA

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Southern Westerlies in Central Chile during the two last glacial cycles as documented by coastal aeolian sand deposits and intercalating palaeosols

Veit

Preusser

Trauerstein

2015

CATENA

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“…La caracterización del evento El Niño, mediante foraminíferos planctónicos, ha sido realizada por Marchant et al (1998Marchant et al ( , 2004Marchant et al ( , 2007, Coloma et al (2005) y Mohtadi et al (2005). Marchant et al (1998) frente a Coquimbo (30ºS), registraron la presencia de 17 especies bajo condiciones normales y 19 especies durante el evento El Niño 1991-92.…”

Section: Introductionunclassified

“…Mediante isótopos de carbono, se han reconocido dos áreas de alta productividad en la costa chilena: 1) en el área norte (24°S y entre los 30-33°S) donde las especies dominantes son: G. bulloides, N. pachyderma y G. glutinata, debido a la surgencia costera y 2) al sur de 39°S, donde las especies dominantes son N. incompta y N. dutertrei en ausencia del afloramiento costero (Mohtadi et al 2005;Marchant et al 2007).…”

Section: Introductionunclassified

Variaciones estacionales de los foraminiferos planctonicos durante 2005 2006 frente a Iquique (20ºS) y Concepcion (36ºS), Chile

Gajardo

Marchant

2012

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RESUMEN. Se estudió por primera vez las variaciones estacionales de los foraminíferos planctónicos frente a las costas de Iquique (20ºS, 70ºW) y Concepción (36ºS, 74ºW), Chile. Las muestras fueron recolectadas mediante trampas de sedimentos ubicadas en dos profundidades: 1.000 y 2.300 m, entre septiembre y diciembre 2005, bajo condiciones normales (con surgencias permanentes y ausencia del evento El Niño) en la zona norte, y entre enero y octubre durante el evento El Niño 2006 en la zona sur (con surgencias estacionales). Se determinó un total de 23 especies, 22 de las cuales se recolectaron frente a Iquique y 16 frente a Concepción. Además, se determinó el flujo de carbonato de calcio de foraminíferos, flujo de individuos y diversidad para definir patrones faunísticos en dichas áreas, de diferentes condiciones oceanográficas. Los resultados mostraron que en Iquique, bajo condiciones normales, se produjo un constante flujo de individuos y carbonato, con máximos en septiembre y octubre 2005, confirmando la presencia de surgencia costera en este período. Por el contrario, en Concepción, bajo condiciones El Niño (2006), el flujo de individuos y carbonato de calcio presentó máximos durante la época estival evidenciando surgencias, que sin embargo, son de menor duración (enero-febrero) respecto a lo descrito en condiciones normales para esta área. La diversidad fue mayor a menor en profundidad en ambas zonas, permaneciendo constante durante todo el período en la zona norte, a diferencia de la zona sur, cuyos mayores valores se observaron durante la época estival coincidiendo con los afloramientos costeros en esta área. Palabras clave: foraminíferos planctónicos, surgencia costera, Iquique, Concepción, El Niño, Chile. Seasonal variations of planktic foraminifera during 2005-2006 off Iquique (20ºS) and Concepción (36ºS), ChileABSTRACT. We studied for first time the seasonal variations of planktic foraminifera off Iquique (20ºS, 70ºW) and Concepcion (36ºS, 74ºW), Chile. The samples were collected by sediment traps located at two depths: 1000 and 2300 m between September and December 2005, under normal conditions (with permanent upwelling and the absence of El Niño) in the northern area and between January and October during the event El Niño 2006, in the southern area (with seasonal upwelling). In this study we determined in total 23 species, 22 which were collected off Iquique and 16 off Concepción. Furthermore, we determined the following parameters: carbonate and individual fluxes and the diversity in order to define faunal patterns in these areas in different oceanographic conditions. The results show that off Iquique (20°S) under normal conditions, there is a constant individual and carbonate flux, with peaks in September and October 2005 reaffirming the presence of coastal upwelling in this period. In contrast, off Concepción, under El Niño 2006, the individuals and calcium carbonate fluxes exhibits maxima during the summer upwelling showing however are of shorter duration (January-February) compared to that descri...

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Soil electrical resistivity monitoring as a practical tool for evaluating irrigation systems efficiency at the orchard scale: a case study in a vineyard in Central Chile

et al. 2020

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In many orchards, irrigation scheduling is designed based on data from meteorological networks and considering homogeneous soil properties. Such assumptions may result in inefficient irrigation, which is difficult to constrain without expensive or invasive techniques. Here we have evaluated the ability of the electrical resistivity tomography (ERT) for detecting meterscale irrigation uniformity and deep percolation during irrigation. The spatiotemporal variability of soil volumetric water content (VWC) in a vineyard located near Santiago (Chile) was inferred using ERT monitoring of two irrigation cycles. The electrical resistivity structure up to 4 m depth was estimated using two-dimensional inversion of ERT data. ERT results were verified by comparing resistivity models with VWC measured with soil moisture sensors, soil properties mapped in a 2 m-depth soil pit, and the spatiotemporal evolution of VWC obtained by solving numerically Richards equation. Largest temporal variations of resistivity were observed within the root depth (1 m) and are consistent with expected relative changes in VWC during irrigation. ERT images exhibit lateral changes in resistivity at these depths, likely indicating non-uniform infiltration of water controlled by observed soil texture variations. Resistivity changes were also observed below the root zone, suggesting that a fraction of the irrigation water percolates downward. These findings can be explained by an excess of irrigation water applied during the monitoring, which was planned considering regional evapotranspiration (ET) data that overestimated the actual ET measured at the vineyard. Altogether, our results suggest that ERT monitoring during irrigation is a cost-effective tool to constrain the performance of irrigation systems.

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Marine geology, oceanography and climate

Cited by 10 publications

References 0 publications

The Southern Westerlies in Central Chile during the two last glacial cycles as documented by coastal aeolian sand deposits and intercalating palaeosols

The Southern Westerlies in Central Chile during the two last glacial cycles as documented by coastal aeolian sand deposits and intercalating palaeosols

Variaciones estacionales de los foraminiferos planctonicos durante 2005 2006 frente a Iquique (20ºS) y Concepcion (36ºS), Chile

Soil electrical resistivity monitoring as a practical tool for evaluating irrigation systems efficiency at the orchard scale: a case study in a vineyard in Central Chile

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