A Polyethylenetherephthalate (PET) device for sampling freshwater benthic macroinvertebrates

Abstract

A new device to sample freshwater benthic macroinvertebrates was used in a low and sandy stretch of a Brazilian sub-tropical river (the River Cai, Triunfo, RS) and in one of its small tributaries, Bom Jardim brook (Arroio Bom Jardim). In this study, the effectiveness of this device, a PET sampler, was tested at different sites in the river and the brook throughout the four seasons between 2001-2002. Comparisons were made by PCA and ANOVA, both employing a bootstrap procedure based on similarity matrices. The PET sampler proved to be a reliable tool for detection of seasonal and spatial differences in richness, total abundance of organisms, and Shannon's diversity index in both river and brook and is therefore recommended for use in the monitoring of macroinvertebrate communities in this system.

Freshwater sponges from the Pampa Biome, Brazil, with description of a new species of Oncosclera

“…In these latter studies, C. australis was found encrusting the roots of macrophytic vegetation, whereas rocks were the preferred substrate of this species in the Ibirapuitã River. It should be noted that Ezcurra de Drago (1979), Tavares et al (2003) and Volkmer-Ribeiro et al (2007a, 2007b reported the occurrence of minute specimens in the roots of aquatic vegetation, which differs considerably from those recently detected on the rocks at the EPA of Ibirapuitã, when C. australis produces arborescent forms reaching heights of up to 5.0cm. Therefore, the Ibirapuitã River (St. 2) represent an environment with ideal characteristics for this species, such as rocky substrates, reduced flow and water column, besides full light exposure.…”

“…Of the species of sponges identified in the EPA of Ibirapuitã, to date, only C. australis is restricted to the Pampa biome. Its occurrence extends from the north-east of the Pampa Biome, in Rio Grande do Sul State, to the Jacuí Delta (Tavares et al, 2003), the coastal lagoons surrounding the Patos Lagoon (Volkmer-Ribeiro et al, 2007a, 2007b, to the central area of the Argentine Pampa, in Setúbal Lake, Don Felipe Lake, and in waterbodies of Carabajal Island, Province of Santa Fe, all of which constitute environments within the Middle Paraná River flood- plain (Ezcurra de Drago, 1979). The restricted occurrence of C. australis in past aquatic environments of the Cerrado Biome corroborates the proposal put forward by Machado et al (2014).…”

“…(Tavares et al, 2003) or event coastal lentic environments (Volkmer-Ribeiro et al, 2007a, 2007b. Corvospongilla seckti, in spite of being counted as a spongillid, was found now associated with potamolepid sponges, making up assemblages with beige to brown or gray tint, encrusting the basalt continuous bed, which according to Iriondo and Kröling (2008), occurs in the middle and particularly in the low stretches of the river, with deeper, darker and stronger waters.…”

“…The spicule set conformed to the original description of the species (Bonetto and Ezcurra de Drago, 1966) (Figure 3C). Remarks: To date, the records of C. australis are restricted to occurrences in the Pampa Biome, both in Argentina and in Rio Grande do Sul State, as well as in Lake Guaíba (Tavares et al, 2003) and downstream of it, in coastal lagoons surroundings the Laguna dos Patos (Volkmer-Ribeiro et al, 2007a, 2007b. However, sponge spicules from this species have recently been identified in lake sediments from the Pleistocene age in the State of Goiás, acting as an environmental indicator that the climate was previously colder in that region of the country (Machado et al, 2014 The sponge encrusts the solid rocky bottom or loose stones in the river, forming permanent crusts varying in thickness from thin to thick, with occasional needle-like projections of up to 15mm in height ( Figure 2D) with whitish, yellowish or greyish colouring ( Figure 2D).…”

“…The largest number of sponges detected at southern Brazil is in fact of the southern half of Rio Grande do Sul State's provenance, i.e. the Brazilian part of the Pampa Biome (De Rosa-Barbosa, 1984;Fontoura et al, 2004;Silva and Volkmer-Ribeiro, l998;Tavares et al, 2003, Volkmer-Ribeiro et al, 2007a, 2007b). It should be noted that these studies, particularly those obtained from the western edge of the Brazilian Pampa, are isolated, and in no way represent a comprehensive survey of the sponge fauna of the region, or even of the sampled water bodies.…”