Composition and richness of monogonont rotifers from La Plata River Basin, South America

Abstract

We present here the first study that analyzed the composition and richness of rotifers of the entire La Plata River basin, the second largest in South America, based on simultaneous and standardized sampling. Fifteen large reservoirs and eight river stretches were selected in the upper, middle, and lower portions of the Paraná, Paraguay, and Uruguay Rivers, which are the major rivers of the La Plata basin. We took a total of 86 samples (open water habitats) in 2010. A mean of 27±11 species per sub-basin was found, with the highest richness in the Lower Paraná (41 species), followed by the Paranapanema (40 species) and Lower Uruguay (38 species). Low richness was observed in the Middle Uruguay and Middle Paraná. We found 106 species belonging to 21 families and two orders. The family with the highest number of species was Lecanidae (21), followed by Brachionidae (20), Trichocercidae (9), and Synchaetidae (8). The species with higher occurrences were Conochilus dossuarius, Kellicottia bostoniensis, Keratella americana, Keratella cochlearis and Hexarthra mira. New occurrences of rotifers were registered for Brazil (Colurella adriatica), São Paulo State (Enteroplea lacustris), and Argentina (Gastropus hyptopus, Harringia rousseleti and Lecane thienemanni). Spearman correlation between the number of species and physical and chemical variables demonstrated positive correlation with chlorophyll and temperature, and negative correlation with dissolved oxygen. We extend the distribution list for some native (Lecane ludwigii) and non-native species of rotifers (K. bostoniensis). We also list the monogonont rotifer species found at the sampling stations.

Diversidad Y Estructura De La Comunidad Zooplanctónica en La Ciénaga De Paredes

“…El 67 % de especies estaba constituido por rotíferos, similar a lo reportado para otros cuerpos de agua ubicados en llanuras de inundación en Suramérica (Ibáñez, 2000;Jaramillo y Aguirre, 2012). La alta riqueza y abundancia de rotíferos puede ser explicada por la alta oferta de materia orgánica que ofrecen estos sistemas cenagosos, además estos organismos se pueden ver favorecidos por la tolerancia que tienen a las fluctuaciones ambientales (Gallo et al, 2009;Gebrehiwot et al, 2017;Martins et al, 2020;Neves et al, 2003). Las mayores abundancias para todos los meses de estudio correspondieron a Keratella americana y Lecane proiecta, estas especies permiten dar una idea del estado trófico de la ciénaga de Paredes, debido a que estos organismos se presentan en sistemas eutrofizados, con alta carga de nutrientes y materia orgánica (Pinheiro et al, 2019;Umaña y Avilés, 2019;Villabona et al, 2014), estos organismos son oportunistas, de estrategia R, ciclo de vida corto y alta tolerancia a la variabilidad en los factores ambientales (Neves et al, 2003).…”

An overview of vinasse pollution in aquatic ecosystems in Brazil

“…Brazilian freshwaters are renowned for their high taxonomic, genetic, functional, and ecological biodiversity (Agostinho et al 2005;Brito et al 2020;Martins et al 2020;Dias-Silva et al 2021). For example, more than 3 000 species of freshwater fish have been described (ICMBio 2018).…”

Diversity, Composition and Environmental Relations of Periphytic Rotifer Assemblages in Lentic Freshwater Bodies (Flanders, Lower Belgium)

“…Taxonomic difficulties and the cumbersome analysis of samples rich in algae and detrital matter are obvious reasons why there are few more extensive studies on periphytic rotifers. Moreover, the common use of net-haul or tube samples collecting a rather erratic mixture of planktonic and littoral communities (e.g., [41,[45][46][47][48]), or collective treatment of different sample types [49][50][51], possibly confound habitat-specific relations, whilst biodi-versity comparisons from water-column samples of waterbodies with strongly different proportions of periphytic and pelagic habitat [52] will invariably be biased. Additionally, many planktonic taxa also occur in the periphyton and the community structure of both habitats is reciprocally influenced [28,53], complicating the picture.…”