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

Abstract

-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...

Associations of ostracods in shallow lakes in the northeast of La Pampa province (Argentina)

“…Considering the clustering of taxa registered in this study, H. similis and H. incongruens, previously found in La Pampa (Kihn & Pall, 2013;Kihn et al, 2017), can tolerate a wide range of salinity and are widely distributed in South America (Ramírez, 1967;Martens & Behen, 1994;César et al, 2001;Laprida, 2006). Heterocypris incongruens, is a cosmopolitan species (Külköylüoğlu, 2013;Fernández et al, 2016) frequently found in Buenos Aires Province (Ramírez, 1967;Laprida, 2006) and Patagonia (Schwalb et al, 2002;Cusminsky et al, 2005;2011) that could be used as an indicator of water pollution (Van der Meeren et al, 2010).…”

“…Among the taxa found in the lowest-salinity lakes, C. incisa is widely distributed in subsaline, shallow, vegetated, and chlorinated sodium lakes of South America and Argentina (Ramírez, 1967;Martens & Behen, 1994;César et al, 2001;Laprida, 2006;Díaz & Lopretto, 2011;Kihn et al, 2017). These conditions were found in DMo, and LTE, which have coverage of Schoenoplectus californicus in the Pampean lakes bicarbonate predominates.…”

“…In La Pampa Province, located in the center of Argentina, studies on the taxonomy, distribution, and ecology of ostracods are very scarce, existing only those of Khin & Pall (2013); Kihn et al (2017) and Coviaga et al (2018). Therefore, the objective of the present study is to determine the taxonomic composition, the density of ostracods, and their relationships with the main limnological parameters in shallow and relatively small lakes with different characteristics in the northeast of La Pampa province.…”

A 700-year multiproxy reconstruction on the Argentinian Pampas inferred from the sediments of Laguna Blanca Grande

“…Ostracods also showed the highest total values and a more continuous presence, supporting the idea of decreasing lake levels. In particular, L. cusminskyae dominated the assemblage, which, together with H. incrongruens, might also indicate oscillations in lake levels and subsequent conductivity variations (Kihn et al, 2017;Laprida and Valero-Garcés, 2009;Marquez et al, 2016). Lake level fluctuations with a progressive reduction of level from 1340 AD to 1900 AD are ascribed to drier conditions and frequent extreme events registered in the Pampean region during the LIA (Córdoba, 2012;Córdoba et al, 2014;Guerra et al, 2017;Piovano et al, 2009).…”

Ostracods from the estuarine zone of the Mar Chiquita coastal lagoon (Buenos Aires Province, Argentina)

“…Se encontraron especímenes vivos en las lagunas bonaerenses de Chascomús, Salada Grande, Los Horcones, del Monte y en el Arroyo Grande (Laprida, 2006); en la laguna Asansa (Río Negro) (Coviaga, 2015) y en las lagunas Monte de Caldén, General Campos y Don Tomás (La Pampa) (Kihn et al, 2017b). La especie ha sido registrada en la provincia de Buenos Aires en sedimentos del Pleistoceno Tardío de la laguna Mar Chiquita (Ferrero, 2009) y de la cantera "Nicolás Vignogna III", en el partido de Marcos Paz (Iacona & Carignano, 2018) y en sedimentos holocenos de los ríos Napostá Grande (Bertels & Martínez, 1990Martínez, , 1997 y Quequén Grande (Ferrero, 1996;Zárate et al, 1998), las lagunas Hinojales (Prieto et al, 1998), La Brava (Plastani, 2016;, La Barrosa (Plastani, 2016;Plastani et al, 2019), Cabeza de Buey (Plastani, 2016) y Blanca Grande (López Blanco et al, 2021), los arroyos Chico (Plastani, 2016) y San Miguel (Ramos et al, 2019) y el Canal 15 (Laprida, 1998;Bertels-Psotka & Laprida, 1998).…”