Cecília Volkmer-Ribeiro

Variations of the Amazonian rainforest environment: a sedimentological record covering 30,000 years

Abstract Two cores (CSS 2 and CSS 10) were collected from two lakes situated in the Carajas area (6°35′S, 49°30′W) that show different stages of silting up. The results of geochemical and petrographic organic analyses, backed up by 14 C radiometric dating, lead to a reconstruction of the variations in the hydrological regime of these lakes over the last 30,000 years. Evidence is revealed for a period of drying up, characterized by a sedimentary hiatus between 22,000 and 13,000 14 C years BP, followed by a period of refilling between 13,000 and 11,000 14 C years BP. (15,400–12,900 cal years BP). The latter interval is primarily characterized by a mainly clastic sedimentary input rich in quartz, kaolinite and iron hydroxides, leading on to the authigenic formation of siderite. This type of sedimentation implies the erosion of the small catchment basin during periods of transition between arid and humid climatic regimes. From 8000 to 4000 14 C years BP (8900–4500 cal years BP), as well as from 2700 to 1500 14 C years BP (2780–1360 cal years BP), special hydrological conditions prevailed. They are characterized in the sedimentary record by the presence of micro-laminae containing wood charcoal interlayered with sponge spicule material. This interlamination reflects the rapid alternation of dry and humid periods. A comparison with the results obtained by pollen analysis shows that sedimentological indicators, once filtered for strictly local effects, can provide a full record of the regional-scale variations in the environment.

Freshwater sponge spicules: a new agent of ocular pathology

In a recent outbreak of human ocular injuries that occurred in the town of Araguatins, at the right bank of Araguaia river, state of Tocantins, Brazil, along the low water period of 2005, two patients (8 and 12-year-old boys) presented inferior adherent leukoma in the left eye (OS), and peripherical uveites, with snowbanking in the inferior pars plana. The third one (13-year-old girl) showed posterior uveites in OS, also with snowbanking. Histopathological analysis of lensectomy material from the three patients and vitrectomy from the last one revealed several silicious spicules (gemmoscleres) of the freshwater sponges Drulia uruguayensis and D. ctenosclera. This work brings material evidences, for the first time in the literature, that freshwater sponge spicules may be a surprising new etiological agent of ocular pathology.

Primeiro registro de Corvoheteromeyenia australis (Bonetto & Ezcurra de Drago) para o Brasil com chave taxonômica para os poríferos do Parque Estadual Delta do Jacuí, Rio Grande do Sul, Brasil

A taxonomic key is provided for the assembly of sponges of the floating meadows, in a protected deltaic area at southern Brazil. The roots of the water hyacinths Eichhornia azurea (Sw). Kunth and Eichhornia crassipes (Mart.) Solms-Laubach were seen to be the prefered substrates. The register of C. australis (Bonetto & Ezcurra de Drago, 1966) is the first for Brazil enhancing a discussion of the genus.

Freshwater sponges (Porifera, Demospongiae) indicators of some coastal habitats in South America: redescriptions and key to identification

Surveys for freshwater sponges were performed at several water bodies at sandy environments along a north-south direction of particularly the Brazilian coastal line. The results allowed for the distinction of four different species-specific environments along this coastal border. The main fact considered was the dominant or the sole recurrent occurrence of a single sponge species at one particular habitat. The first one is that of the lagoonal mesohaline habitats at the tropical and subtropical realms, indicated by Spongilla alba Carter, 1849. The second one refers to shallow ponds among dunes at the tropical area indicated by Corvoheteromeyenia heterosclera (Ezcurra de Drago, 1974). The third one is that of also shallow ponds close to the dune belt at the temperate region indicated by Racekiela sheilae (Volkmer-Ribeiro, De Rosa-Barbosa & Tavares, 1988). The fourth one is that of organically enriched environments, at the marginal areas of lagoons and mouth of small rivers, evolving towards freshwater muddy ponds and coastal swamps, not far from the ocean border: Ephydatia facunda Weltner, 1895 is the species to occupy this habitat with almost exclusiveness. The above species are thus proposed as indicators of such habitats and have their descriptions improved and that of their environments summarized. A taxonomic key based on the spicules of the four species is proposed. The results presented aim to contribute to the identification of spicules of these sponges in sediment columns recovered at the Brazilian and South American coastal area. Determination of paleo ocean borders are a present issue of upmost importance in what respects projections of timing and fluctuations of ascending/regressing sea levels.

Comunidades de esponjas do curso superior dos rios Paraná (Goiás) e Paraguai (Mato Grosso), Brasil, com redescrição de Oncosclera schubarti (Bonetto & Ezcurra de Drago)

An extensive survey for freshwater sponges was carried at the temporarely exposed rocky bottoms of river Corumba at Goias State and river Manso at Mato Grosso State. The exposure resulted from the closing of the dams for lake formation at the respective Hidreletric Power Plants. Drulia uruguayensis Bonetto & Ezcurra de Drago, 1968, Corvospongilla seckti Bonetto & Ezcurra de Drago, 1966 and Trochospongilla repens (Hinde, 1888) were seen to be common to both rivers. Eunapiusfragilis (Leidy, 1851), Oncosclera navicella (Carter, 1881) and O. petricola (Bonetto & Ezcurra de Drago, 1969) were yet found in river Manso and O. schubarti (Bonetto & Ezcurra de Drago, 1967) in river Corumba. O. schubarti is redescribed and SEM illustrated.

Inventary of the Sponge Fauna of the cemitério Paleolake, Catalão, Goiás, Brazil

The Cemitério Paleolake, Catalão, Goiás, is a lacustrine deposit that is rich in spicules of continental sponges. These spicules, which are present in three sections (1-3), were analyzed for the taxonomic identification of the species in order to reconstruct the late Quaternary palaeoenvironment. An indigenous assemblage of lentic sponges was found, consisting of Metania spinata (Carter 1881), Dosilia pydanieli Volkmer-Ribeiro (1992), Radiospongilla amazonensis Volkmer-Ribeiro and Maciel (1983), Trochospongilla variabilis Bonetto and Ezcurra de Drago (1973), Corvomeyenia thumi (Traxler 1895), Heterorotula fistula Volkmer-Ribeiro and Motta (1995), plus Corvoheteromeyenia australis (Bonetto and Ezcurra de Drago 1966), which here has its first record in an assemblage formed by biosiliceous deposits. Furthermore, at the base of the sections, spicules of sponges from lotic environments were detected, including Corvospongilla seckti Bonetto and Ezcurra de Drago (1966), Oncosclera navicella (Carter 1881) and Eunapius fragilis (Leidy 1851), which suggests a contribution from flowing water. We identified 25 spongofacies horizons caused by sponge assemblages typical of a lentic environment, dated from at least 39,700 years BP., and currently occurring in lakes typical of the Cerrado Biome.

Freshwater sponges (Porifera, Demospongiae) in a benthic filter feeding community at the Guanacaste Dry Forest, Costa Rica

As esponjas de agua doce Trochospongilla variabilis Bonetto & Ezcurra de Drago (1973), Radiospongilla crateriformis (Potts, 1882), Spongilla cenota Penney & Racek (1968) e Corvoheteromeyenia heterosclera (Ezcurra de Drago, 1974) compoem, com o bivalve esferideo Eupera cubensis (Prime, 1865) e diversos briozoarios Phylactolaemata, uma comunidade bentica de filtradores em ambientes sazonais lenticos e loticos com alto Carbono Orgânico Particulado (POC), baixa condutividade e pH acido no bioma da Floresta Decidual da Costa Rica. Os especimes de esponjas coligidos conduziram a redescricao das quatro especies.

Levantamento de cauxi (Porifera, Demospongiae), provável agente etiológico de doença ocular em humanos, Araguatins, rio Araguaia, Estado do Tocantins, Brasil

The recent outbreak of human ocular injuries, most in the conjunctive, occurred in the town of Araguatins, at the right bank of Araguaia river, State of Tocantins, Brazil, along the low water period of 2005, affected particularly male children and adults and had as main characteristic eye irritation and itching after bathing and diving with open eyes in the river waters, followed by appearance of ocular injuries. The large number of registers of itching and ulceration caused by sponge (cauxi) spicules in rivers of Central Amazonia urged the authors to undertake a survey for sponges and its spicules in the river waters and sediments in several GPS referred stations at the site. Ten sponge species were detected upon the finding of gemmules as well as upon spicules accumulated in the river sediments or suspended in the river waters. The ten species are listed and have their spicules illustrated aiming their detection in surgically extracted ocular damaged tissues, the determination of the disease etiology and the procedures to be taken by local health authorities to prevent further progress of the disease.

Espongofauna da Área de Proteção Ambiental Meandros do rio Araguaia (GO, MT, TO), Brasil, com descrição de Heteromeyenia cristalina sp. nov. (Porifera, Demospongiae)

A Area de Protecao Ambiental Meandros do rio Araguaia abrange um trecho do rio Araguaia com sua complexa rede de meandros e tributarios sazonalmente inundados. Foi realizado um levantamento da fauna de esponjas, visando estabelecer os fundamentos taxonomicos para uma correlacao futura com os distintos habitats aquaticos e suas caracteristicas fisicas, quimicas, alem do conteudo de espiculas em seus sedimentos. As amostragens foram realizadas em seis expedicoes, quatro em epoca de aguas baixas (2002-2005) e duas em periodo de aguas altas (2004-2005), contemplando 27 estacoes georreferenciadas. Heteromeyenia cristalina sp. nov. e descrita e incluida na chave apresentada para as esponjas da area da APA.

A Polyethylenetherephthalate (PET) device for sampling freshwater benthic macroinvertebrates

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 Shannons diversity index in both river and brook and is therefore recommended for use in the monitoring of macroinvertebrate communities in this system.