Modern diatoms from a temperate river in South America: the Colorado River (North Patagonia, Argentina)

Vélez-Agudelo, Camilo; Espinosa, Marcela A.; Fayó, Rocío; Isla, Federico Ignacio

doi:10.1080/0269249x.2017.1321046

Cited by 18 publications

(15 citation statements)

References 58 publications

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“…El río posee un régimen pluvio-nival con caudales anuales promedio de 140 m 3 s -1 y alcanza valores máximos estacionales durante primavera-verano (818 m 3 s -1 ; González Uriarte, 1984). Presenta aguas levemente alcalinas durante todo el año (pH = 8,35 ± 0,58), mientras que otras variables ambientales muestran un patrón estacional (Biasotti et al, 2013;Vélez-Agudelo et al, 2017). El río Colorado posee un mayor rango de salinidad respecto a otros ríos patagónicos (Espinosa & Isla, 2015), con menor tenor salino durante en los meses de primavera-verano (0,56 ± 0,06) y mayor en invierno (0,84 ± 0,13) cuando el caudal es mínimo (Vélez-Agudelo et al, 2017).…”

Section: áRea De Estudiounclassified

“…Las diatomeas fueron clasificadas en relación con sus tolerancias a la salinidad y formas de vida, siguiendo la clasificación ecológica de Vos & de Wolf (1993), Denys (1991Denys ( /1992) y estudios ecológicos regionales complementarios (e.g. Echazú, 2012;Vélez-Agudelo et al, 2017). Las zonas diatomológicas fueron definidas utilizando el análisis de agrupamiento jerárquico restringido (constrained hierarchical clustering -CONISS) y la distancia de Bray Curtis.…”

Section: Análisis De Datosunclassified

“…De forma consistente, los análisis filogenéticos de Fragilariaceae indican un origen parafilético (Medlin et al, 2012;Theriot et al, 2015). Desde la perspectiva ecológica las fragilarioides pequeñas son ubicuas en el ambiente y por lo general coexisten en los ensambles; en este sentido, un diagnóstico taxonómico inespecífico también interfiere en la determinación de sus afinidades ecológicas (Schmidt et al, 2004;Vélez-Agudelo et al, 2017).…”

Section: Introductionunclassified

“…Las fragilarioides pequeñas son abundantes en los ambientes ácueos actuales de Argentina, tanto naturales como artificiales. Han sido ampliamente identificadas en muestras de sedimento superficial, perifiton y en el plancton de lagos, ríos, arroyos, humedales, estanques y embalses (Maidana & Díaz-Villanueva, 2001;Espinosa & Isla, 2015;Vélez-Agudelo et al, 2017). También se han registrado en secuencias sedimentarias de estuarios y ambientes continentales de Buenos Aires y Patagonia (Espinosa, 2008;Escandell et al, 2009;Hassan et al, 2009Hassan et al, , 2011Espinosa et al, 2012;Fayó & Espinosa, 2014).…”

Section: Introductionunclassified

“…Sin embargo, estos antecedentes no hacen referencia a la presencia de diatomeas arrafídeas pennadas pequeñas en los ensambles. Vélez-Agudelo et al (2017) estudiaron la composición y distribución espacial de la flora diatomológica moderna contendida en sedimentos superficiales de la cuenca media e inferior del río Colorado y establecieron el primer registro en Argentina de dos especies del género Punctastriata: P. glubokoensis Williams, Chudaev & Gololobova y P. lancettula Schumann Hamilton & Siver, e identificaron a Staurosira venter (Ehrenberg) Cleve & Möller como la especie dominante de los ensambles fluviales salobre-dulceacuícolas. Respecto al registro fósil, las sucesiones sedimentarias holocenas de la llanura deltaica del río Colorado se encuentran prácticamente inexploradas desde una perspectiva diatomológica.…”

Section: Introductionunclassified

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Diatomeas holocenas del delta del río Colorado, Argentina. Una aproximación paleoambiental a partir del estudio de “fragilarioides pequeñas”

Fayó

Espinosa

Isla

2020

Rev. bras. paleontol.

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Holocene diatoms of the Colorado River Delta, Argentina. A paleoenvironmental approach from the study of "small fragilarioids". Diatom assemblages of a sedimentary succession in the deltaic plain of the Colorado River (Argentina) were studied in order to reconstruct the paleoenvironmental conditions of the delta in response to Holocene sea-level changes. A 191 cm depth core was extracted by vibracoring from Las Isletas (LI), located 22 km from the coast (39°43'5.7"S, 62°20'49.7"W). A cluster analysis -CONISS of 35 subsamples defined three diatom zones (DZ). The sedimentary succession is dominated by small fragilarioids, being Punctastriata glubokoensis Williams, Chudaev & Gololobova the most abundant species; the accompanying flora included fresh-brackish and allochthonous marine-coastal taxa. At the base, subzone DZIA (191-163 cm, 7,315±64 14 C yr BP) included sandy lithological units and presented abundant marine-coastal species. The overlying subzone DZIB (163-96 cm) has low abundance of allochthonous marine species. The uppermost zone, DZII (96 cm from the top) integrate the silt-sandy lithological units, and it was deposited ca. 2,218±29 14 C yr BP. DZII lacked marine species. The LI sequence represents the infilling of a river-estuarine channel with tidal influence ca. 7,300 14 C yr BP that gradually evolved into a fresh-brackish river channel, similar to the current river, ca. 2,200 14 C yr BP. During the Middle Holocene transgression, the greatest marine influence would have transported coastal marine species upstream to the LI site; the increase of fluvial influence associated with the progradation of the delta lobe would have favored the ubiquity and persistence of the small fragilarioids in the fluvial-delta assemblages of the Colorado River during the last ca. 7,000 14 C yr BP.

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Section: áRea De Estudiounclassified

Section: Análisis De Datosunclassified

Section: Introductionunclassified

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Diatomeas holocenas del delta del río Colorado, Argentina. Una aproximación paleoambiental a partir del estudio de “fragilarioides pequeñas”

Fayó

Espinosa

Isla

2020

Rev. bras. paleontol.

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Response of diatom assemblages to orbital‐ and millennial‐scale climatic variability since the penultimate glacial maximum in the northern limit of the Neotropics

Avendaño

Caballero-Miranda

Ortega‐Guerrero

et al. 2023

J Quaternary Science

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Lake Chalco, in Central Mexico, has a long diatom record which provides an excellent opportunity to document the biotic and hydrological responses of this ecosystem to orbital‐ and millennial‐scale climatic variability during the last 150 ka. Detrended correspondence analysis was used to evaluate the ecological turnover and to identify diatom species associations throughout the sequence. Millennial‐scale climatic fluctuations were identified as peaks in freshwater (mostly small Fragilariaceae spp.) or as peaks in salt‐tolerant species. At orbital scales, species turnover involved changes between freshwater assemblages dominated by Stephanodiscus spp. – small Fragilariaceae spp. – Cocconeis placentula, present during low‐evaporation, cool intervals [late Marine Isotope Stage (MIS)6, MIS5d, MIS2] against salt‐tolerant taxa, dominated by Stephanocyclus and Cyclotella spp., in higher evaporation, higher salinity conditions (MIS5e, MIS5c–a, MIS4, MIS3, early MIS1). Comparatively, MIS6 and MIS5d seem to have been cooler (~ −6 to −7 °C) and wetter than MIS2 (~ − 4 to −5 °C). In contrast, MIS5e and early MIS1 (11.5–6 ka) had similar warmer, low lake level, saline conditions. In addition, MIS5 was a period of intense climatic change associated with wide‐amplitude orbital forcing that favored a Stephanocyclus–Cyclotella spp. ecological succession (S. meneghinianus, C. tlalocii, C. poyeka, S. quillensis). In contrast, smaller temperature changes were inferred during MIS4 and MIS3.

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Diatom-based inference model for conductivity reconstructions in dryland river systems from north Patagonia, Argentina

2021

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Dryland river systems support a diverse aquatic biota in semi-arid and arid landscapes, but they are increasingly vulnerable to natural and human impacts. This study provides the first modern diatom training set (n = 38) from three dryland rivers in northern Patagonia, Argentina. The relationship between surface-sediment diatoms and contemporary environmental variables was explored using multivariate analyses. The results showed that surface-water chemistry varies among rivers in accordance with local-scale factors such hydro-climatic variability and anthropic activities. A total of 378 diatom taxa were identified but only 45 taxa occurred with relative abundances higher than 2% in at least one sediment sample. The Colorado and Negro rivers were characterized by high abundances of small tychoplanktic fragilarioids whereas the Chubut River was dominated by epiphytic and planktic taxa. The canonical correspondence analyses (CCA) showed that conductivity, pH and HCO 3 − were the main environmental variables governing diatoms distributions. A transfer function was developed for water conductivity using unimodal methods because of partial CCA and λ 1 /λ 2 ratio revealed that this variable had the largest unique effect on diatom variance. A weighted averaging (WA) model with tolerance downweighting and classic deshrinking provided a reasonably robust model (r 2 jack = 0.94 and RMSEP = 0.249 log 10 μS cm −1 ). However, the diatom-inferred conductivity values should be carefully interpreted because of the uneven distribution of sampling sites and the dominance of small araphid diatoms belonging to the genera Staurosira, Pseudostaurosira and Punctastriata. By their benthic habitat, the distribution of these taxa could be influenced by other factors as light and substrate in addition to water chemistry. The autoecological information achieved through this study will provide the basis for a better insight into the hydrological responses of the dryland rivers in northern Patagonia to climate and environmental changes.

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Modern diatoms from a temperate river in South America: the Colorado River (North Patagonia, Argentina)

Cited by 18 publications

References 58 publications

Diatomeas holocenas del delta del río Colorado, Argentina. Una aproximación paleoambiental a partir del estudio de “fragilarioides pequeñas”

Diatomeas holocenas del delta del río Colorado, Argentina. Una aproximación paleoambiental a partir del estudio de “fragilarioides pequeñas”

Response of diatom assemblages to orbital‐ and millennial‐scale climatic variability since the penultimate glacial maximum in the northern limit of the Neotropics

Diatom-based inference model for conductivity reconstructions in dryland river systems from north Patagonia, Argentina

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