Assemblage diversity and isotopic signals of modern ostracodes and host waters from Patagonia, Argentina

Schwalb, Antje; Burns, Stephen J.; Cusminsky, Gabriela Catalina; Kelts, Kerry; Markgraf, Vera

doi:10.1016/s0031-0182(02)00484-4

Cited by 73 publications

(85 citation statements)

References 31 publications

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“…Es una especie de distribución cosmopolita; en América del Sur se la registró en Argentina, Brasil, Uruguay y Venezuela (Kotzian, 1974;Purper & Würdig-Maciel, 1974;Martens & Behen, 1994). Es frecuente en sedimentos no marinos del Cuaternario de la provincia de Buenos Aires (Ferrero, 1996) y en ambientes actuales del norte de la Patagonia (Schwalb et al, 2002) y provincia de Buenos Aires (Laprida, 2006 Distribución geográfica. Especie de distribución cosmopolita; en Sudamérica se la encuentra en ambientes actuales de Argentina, Brasil, Paraguay, Uruguay y Venezuela (Martens & Behen, 1994;César et al, 2004); en Argentina fue recuperada de localidades cuaternarias desde el Chaco hasta la Patagonia (Zabert, 1981;Zabert & Herbst, 1986;Cusminsky, 1995;Laprida, 2006), en sedimentos holocenos del curso medio y desembocadura del Arroyo Napostá Grande, Bahía Blanca, Buenos Aires (Martínez, 2002) y en sedimentos actuales del estuario de Bahía Blanca (Martínez, 2005).…”

Section: -Ostrácodos De Lagos Someros Argentinaunclassified

“…Según Schwalb (2002) Heterocypris incongruens es una especie típica de ambientes temporales y su ciclo de vida corto es considerado una adaptación favorable para desarrollarse en ambientes inestables (Ganning, 1971), además es considerada una especie oportunista omnívora (Reichholf, 1983). Como se mencionó con anterioridad, los lagos estudiados en el presente trabajo son ambientes muy inestables debido a sus retracciones y expansiones; esto explicaría la presencia y abundancia de H. incongruens en todos los lagos analizados ya que es una especie que se adapta rápidamente a variaciones en el ambiente.…”

Section: -Ostrácodos De Lagos Someros Argentinaunclassified

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Ostrácodos de lagos someros de la región central de Argentina: implicaciones paleolimnológicas

Kihn¹,

Crespo²,

Pall³

2017

Rev. bras. paleontol.

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-OSTRACODS OF SHALLOW LAKES OF THE CENTRAL REGION OF ARGENTINA: PALEOLIMNOLOGICALIMPLICATIONS. Studies about ostracods in shallow lakes are very scarce in the Province of La Pampa, thus the objective of this work is to contribute to the knowledge of the species present in lentic environments, studying the distribution, abundance, and specific associations of ostracods. The samples come from four shallow lakes of the Pampean Region, Province of La Pampa, Argentina. Sampling was performed along transects perpendicular to the shore. Five genera represented by six species of benthic ostracods were identified. Heterocypris similis was present in all sampled water bodies, but was dominant in the Monte de Caldén (LCM) and Don Tomás (LDT) lagoons. Cypridopsis vidua was very abundant in the LCM. The species Chlamydotheca incisa and Potamocypris unicaudata were only recorded in the Ojo de Agua Lagoon (LCS). C. incisa is recorded for the first time in the province, and P. unicaudata in Argentina. The qualitative and quantitative variations of the ostracod assemblages can be related to topography, sedimentology, vegetation and salinity variations. The results of this study are important in the interpretation of the environments recorded during the Quaternary, since these species are also registered as fossils.Key words: ostracods, lakes, La Pampa, modern analogues, Argentina.RESUMO -Estudos sobre ostracodes em lagoas pouco profundas são muito escassos na Província de La Pampa, Argentina, e, portanto, o objetivo deste trabalho é contribuir para o conhecimento das espécies presentes nos ambientes lenticais, estudar distribuição, abundância e associações específicas de ostracodes. As amostras provêm de quatro lagoas da Região Pampeana, Província de La Pampa, Argentina. Amostragem sazonal foi realizada ao longo de um corte transversal perpendicular à costa, tendo sido identificado um total de cinco gêneros representados por seis espécies de ostracodes bentônicos. Heterocypris similis está presente em todos os corpos de água amostrados, mas é dominante nas lagunas Monte de Caldén (LCM) e Don Tomás (LDT). Cypridopsis vidua é muito abundante na LCM. As espécies Chlamydotheca incisa e Potamocypris unicaudata somente foram registradas na Laguna Ojo de Agua (LCS). C. incisa é o primeiro registro para a província e P. unicaudata é a primeira nomeação para a Argentina. As variações qualitativas e quantitativas dos conjuntos ostracodes podem estar relacionadas à topografia, sedimentologia, vegetação e variações de salinidade. Os resultados deste estudo são importantes na interpretação dos ambientes registrados durante o Quaternário, uma vez que estas espécies também ocorrem como fósseis.Palavras-chave: ostracodes, lagoas, La Pampa, análogos modernos, Argentina. INTRODUCCIÓNLos ostrácodos son microcrustáceos bivalvos con caparazón quitino-calcáreo, que habitan todo tipo de medios acuáticos (desde continentales hasta marinos profundos, pasando por los estuarinos); en ambientes continentales su distribución está condicionada por l...

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Section: -Ostrácodos De Lagos Someros Argentinaunclassified

Ostrácodos de lagos someros de la región central de Argentina: implicaciones paleolimnológicas

Kihn¹,

Crespo²,

Pall³

2017

Rev. bras. paleontol.

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“…Samples from 35 freshwater environments in Argentinean Patagonia (Schwalb et al, 2002;Cusminsky et al, 2005) were reviewed. Seven sites had abundant adult valves of E. fontana (n> 3) to be analyzed in this study (Table 1).…”

Section: Study Areamentioning

confidence: 99%

“…This widely distributed species is common in recent assemblages and in quaternary sequences and has been used in ecological and paleoenvironmental studies (Cusminsky and Whatley, 1996;Cusminsky, 1999, 2000;Schwalb et al, 2002;Markgraf et al, 2003;Cusminsky et al, 2005Cusminsky et al, , 2011Ramo´n-Mercau et al, 2012). Eucypris fontana has been recorded in ephemeral as well as in permanent environments, but it reaches its maximum abundance in permanent lakes (Markgraf et al, 2003;Cusminsky et al, 2005Cusminsky et al, , 2011.…”

Section: Introductionmentioning

confidence: 99%

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Eucypris fontana(Graf, 1931) (Crustacea, Ostracoda) in permanent environments of Patagonia Argentina: a geometric morphometric approach

Ramos

Alperín

Pérez

et al. 2015

Ann. Limnol. - Int. J. Lim.

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-Ostracods are microcrustaceans with a calcareous carapace, very useful as paleoenvironmental indicators. Eucypris fontana (Graf, 1931) is a non-marine ostracod species, distributed in southern Neotropics, commonly found in living bisexual populations as well as in quaternary sequences in Patagonia. Geometry morphometric analysis offers efficient and powerful techniques to quantify, describe and analyze shape and size variations. In this study, phenotypic changes in the carapace (size and shape) of E. fontana were analyzed using geometric morphometric methods. One hundred and two valves, including males and females from surface sediments of six permanent water bodies located in Patagonia, Argentina, were analyzed. Male and female valves are spread in the morphospace and sexual dimorphism in size and shape were no perceived. Valve size (centroid size) differed between environments; larger individual were correlated with higher Mg 2+ , Ca 2+ , K + concentrations and temperature and lower pH ( y 9.1) of the host waters, whereas smaller specimens were associated with the opposite environmental extreme. The principal component analysis performed with Procrustes coordinates (shape) indicated a morphological gradient between elongated and rounded valves; major changes occurring on the dorsal margin, calcified inner lamella and in the position of the adductor muscles scars. Rounded carapaces were related whit higher Ca 2+ and Mg 2+ concentration and lower pH ( y 8.6) environments, whereas elongated valves were associated with the opposite environmental extreme. These results highlight the importance of morphometric studies of E. fontana in ecological research and their potential use in paleoenvironmental studies in Patagonia and other regions where this taxon is found.

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Organomineralization processes in freshwater stromatolites: a living example from eastern Patagonia

Pacton

Hunger

Martinuzzi

et al. 2015

The Depositional Record

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Living stromatolites have been mostly described within shallow marine and (hyper)saline lacustrine environments. Southernmost South America lacks detailed investigations of these (organo)sedimentary buildups, particularly in regions experiencing extreme and variable environmental conditions. Here, we report and describe living freshwater stromatolites in the Maquinchao region, north-western Patagonia, Argentina. Fossil stromatolites characterized by globular and cauliflower shapes are also present in a continuous palaeoshoreline of a former lake at an altitude of 830 m, whereas their living counterparts only occur in the calm waters of sheltered or meandering sections of the Maquinchao River. The living stromatolites and their host waters have been sampled and studied using various chemical and microscopic techniques to better constrain the environmental versus biological factors controlling their development. Our results indicate that today stromatolites only proliferate in freshwater when Ca 2+ levels are high. A microscopic inspection of the living stromatolite mat indicates stronger photosynthetic activity in the upper green layer associated with crypto/ microcrystalline calcite (nanoglobules) compared to the lower beige-white biofilm. This biofilm contains more low-Mg calcite (rhombohedra) precipitates, which can form millimetre-sized aggregates in the underlying anoxic layer. Although sulphate-reducing bacteria are living in the entire mat, they appear more abundant and widely distributed in the lower beige-white layer and are always associated with Mg calcite. Low salinity and low-turbidity water along with microbial (photosynthetic and heterotrophic) activity are the most important factors promoting low-Mg calcite precipitation in the Maquinchao Basin. These conditions are very different from those proposed for recently described lacustrine stromatolites at high altitude in the subtropical and tropical Andes as well as in Chilean Patagonia. Hence, all these observations in modern freshwater stromatolites show the importance of geomicrobiological studies in identifying proxies of the hydrological conditions prevailing during their formation.

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Assemblage diversity and isotopic signals of modern ostracodes and host waters from Patagonia, Argentina

Cited by 73 publications

References 31 publications

Ostrácodos de lagos someros de la región central de Argentina: implicaciones paleolimnológicas

Ostrácodos de lagos someros de la región central de Argentina: implicaciones paleolimnológicas

Eucypris fontana(Graf, 1931) (Crustacea, Ostracoda) in permanent environments of Patagonia Argentina: a geometric morphometric approach

Organomineralization processes in freshwater stromatolites: a living example from eastern Patagonia

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