Pristina longiseta reproduction test: chronic exposure to environmental contaminants.

Aquatic worms are considered a suitable group to evaluate the effects of contaminants on the environment, although one of the main challenges is to use the species of local occurrence. Recently, Pristina longiseta was suggested to be used in acute bioassays. In this context, this study aimed to establish a chronic exposure for ecotoxicological bioassays using the cosmopolitan species of occurrence in Brazilian freshwater P. longiseta. Firstly, we tested three exposure times (4, 7, and 10 days) under the presence or absence of aeration for reproduction outputs. After determining the best configuration (7 days without aeration), we assessed the effects of the chronic exposures using the standardized reference substance potassium chloride (KCl), the antibiotic sulfamethoxazole (SMX), the flame retardant tetrabromobisphenol A (TBBPA), and the sugarcane vinasse. Our results showed suitability for applying the chronic exposure using P. longiseta and indicated the sensitivity of the offspring to KCl (EC50-7d = 0.51 g/L). Sulfamethoxazole and TBBPA caused a significant decrease in the offspring of P. longiseta (EC50-7d = 59.9 µg/L and < 62.5 µg/L, respectively). Sugarcane vinasse showed high toxicity for the species, and 4.26% of vinasse was calculated as EC50-7d. Therefore, the described protocol was successfully applied as an ecotoxicological bioassay to evaluate the effects of environmental contaminants on the reproduction rate of the freshwater worm P. longiseta.

Effects of pyrimethanil fungicide on Chironomidae community structure.

The use of agrochemicals in agriculture may impact aquatic ecosystems, particularly influencing the stream insect communities. Among aquatic insects, the family Chironomidae is the most abundant and species-diverse insect group found in freshwater ecosystems. However, in the southern hemisphere, studies with Chironomidae are still sparse, compared to Europe and North America. The present study evaluates the responses of Chironomidae species (Insecta: Diptera) to pyrimethanil fungicide in a mesocosm experiment. Water contamination and chironomid community were monitored over 10 months. After five months of monitoring, the pyrimethanil fungicide was completely degraded and there was a statistically significant increase in the Margalef Richness and Shannon-Wiener Index (H') in the control units when compared with the contaminated mesocosms (p = 0.003). Our results point out that the utilization of agrochemicals can be a harmful factor influencing negatively the Chironomidae populations. This finding has key implications for insect conservation strategies and ecological management environments.

Aquatic oligochaetes (Annelida: Clitellata) in reservoirs in São Paulo State: list of occurrence and ecological observations on the species / Oligoquetos aquáticos (Annelida: Clitellata) em reservatórios no Estado de São Paulo: lista de ocorrência e observações ecológicas das espécies

Abstract: This work sought the survey of species and information about the distribution of the Class Oligochaeta in reservoirs sampled in the Sediment Quality Monitoring Network of CETESB (Environmental Company of the State of São Paulo). As such, this study aimed to inventory the limnic oligochaetes fauna to expand knowledge of the ecology and distribution of this group in reservoirs in the state of São Paulo. Ninety replicates were performed in 12 reservoirs in the state of São Paulo between 2014 and 2016, using van Veen or Ponar samplers in the sublittoral region, and Ekman-Birge in the deep region. Twenty-eight taxa were inventoried, belonging to the families Naididae and Opistocystidae. The species Dero righii and Pristina longisoma were recorded for the first time in São Paulo State, Nais magnaseta and Spirosperma velutina were first recorded in Brazil. The results presented here make this inventory extremely important for understanding the distribution of aquatic oligochaetes throughout the Brazilian territory.

Resumo: Este trabalho buscou o levantamento de espécies e informações sobre a distribuição da Classe Oligochaeta em reservatórios amostrados na Rede de Monitoramento da Qualidade de Sedimentos da CETESB (Companhia Ambiental do Estado de São Paulo). Sendo assim, este estudo objetivou inventariar a fauna de oligoquetos para expandir o conhecimento de ecologia e distribuição deste grupo em reservatórios no Estado de São Paulo. Foram realizadas 90 réplicas em 12 reservatórios no estado de São Paulo entre os anos de 2014 a 2016, utilizando amostradores van Veen ou Ponar na região sublitoral, e Ekman-Birge na região profunda. Foram inventariados 28 táxons, pertencentes às famílias Naididae e Opistocystidae. As espécies Dero righii e Pristina longisoma, foram registradas pela primeira vez no Estado de São Paulo, Nais magnaseta e Spirosperma velutina foram identificadas pela primeira vez no Brasil. Os resultados apresentados aqui tornam este inventário de suma importância para o conhecimento da distribuição dos oligoquetos aquáticos em todo o território brasileiro.

Update on the use of Pristina longiseta Ehrenberg, 1828 (Oligochaeta: Naididae) as a toxicity test organism.

Ecotoxicological bioassays have been widely applied to evaluate the toxicity of substances in standardized test organisms. Nevertheless, the main challenge for researchers is the use of native species to express the effects of pollutants on aquatic biota. Thirty years ago, Smith and collaborators evaluate the possible use of Pristina longiseta (as Pristina leidyi) in acute toxicity test, developing some experiments using cadmium and vanadium as toxicants. The present work aimed to update the use of P. longiseta, in acute bioassays, presenting the occurrence and general characteristics of the species; adaptation of cultivation to tropical conditions; sensitivity tests using potassium chloride (KCl) and copper sulfate (CuSO4) as reference substances standardized by OECD, USEPA, and ABNT; and acute exposure to zinc chloride (ZnCl2). The results showed a successful use of this species as tropical test organism, which presented easy laboratory rearing and responded to the classical ecotoxicological index. The present study can increase the utilization of P. longiseta in bioassays for tropical regions and improve the evaluation of environmental impacts using a native species in ecotoxicological studies.

Dynamics of (total and methyl) mercury in sediment, fish, and crocodiles in an Amazonian Lake and risk assessment of fish consumption to the local population.

Increasing concerns have been raised about the toxicity of mercury (Hg) to humans, especially for those that consume a great amount of fish. High Hg concentrations have previously been measured in Amazonian waterbodies, both resulting from natural and anthropogenic sources. However, few studies have been conducted so far in Amazonian lakes that are fished by local populations. In addition, few of those studies included methylmercury (MeHg), the most toxic and bioaccumulative Hg form, and evaluated the influence of physico-chemical conditions and season on Hg dynamics. In the present study, total Hg (THg) and MeHg concentrations were measured in bottom sediment as well as in two fish and two crocodile species of the Amazonian Cuniã Lake. Bottom sediment MeHg concentrations were higher in the dry season than in the wet season, which is related to differences in physico-chemical (pH and electrical conductivity) conditions. Diet appeared to be related with animal tissue MeHg concentrations, with the herbivorous fish having lower MeHg levels than the predatory fish and crocodiles. Based on the measured tissue concentrations and published data on local person weight and fish consumption, MeHg risk to Cuniã Lake populations was estimated. Although the MeHg fish tissue concentrations did not exceed national and international standards, a significant risk to the local population is anticipated due to their high fish consumption rates. Graphical abstract.

Chironomus sancticaroli (Diptera, Chironomidae) as a Sensitive Test Species: Can We Rely on Its Use After Repeated Generations, Under Laboratory Conditions?

In ecotoxicological assays, previously selected and standardized organism tests are exposed to an environmental sample. Some species of the Chironomus genus have been extensively used in ecotoxicological assays. Among these, Chironomus tentans is usually utilized in the USA and Chironomus sancticaroli in Brazil. We conducted ecotoxicological bioassays to compare a population of C. sancticaroli, kept for 6 years under laboratory conditions, with a sylvatic population of the same species, collected in the field. The aim was to test the hypothesis that populations of C. sancticaroli, maintained in the laboratory for long periods, could have a different response to stressors/substances. We analyzed the responses of C. sancticaroli for potassium chloride, zinc chloride, potassium dichromate, linear alkylbenzene sulphonate (LAS) and caffeine. The results showed no significant differences between the two populations in the analyses and seems to indicate the possible use of C. sancticaroli from populations kept in the laboratory for long periods.

Environmental diagnosis of metals in streams near sugarcane cultivation areas: current and historical analysis in the central region of the State of São Paulo.

In Brazil, innumerable regions of native landcover have been removed and replaced by agricultural cultivation, especially of sugarcane. In this culture, the application of fertilizers containing metals has caused impacts on the water resources causing contamination of stream sediments and occasioning bioaccumulation of metals in aquatic invertebrates. In the year of 2006, an environmental diagnosis of metals in sediments of streams located near sugarcane cultivation areas and in streams located in preserved areas, was published. That study pointed to high concentrations of metals in stream sediments in agricultural areas. These streams have been monitored over the last 10 years conducting analyses of metals and monitoring possible changes in land use. In the present paper, a historical comparison of metals contamination in the sediments of the same streams is conducted, aiming to present a status of 10 years later, analyzing 5 metals (Zn, Cd, Mn, Cr and Fe) found in the sediments of 8 streams, five located in areas of sugarcane cultivation and three located in preserved areas. This study also shows that there is higher concentration of metals in the sediments of streams near sugarcane cultivation than in preserved areas. The temporal historical evaluation showed high concentrations of Cd in 2016 when compared to the year 2006 for streams near sugarcane cultivation.

Oligochaeta (Annelida: Clitellata) in the Juruena River, MT, Brazil: species indicators of substrate types / Oligochaeta (Annelida: Clitellata) do Rio Juruena, MT, Brasil: espécies indicadoras em diferentes substratos

Abstract: Oligochaeta assemblages are important components in freshwater environments, where their abundance and composition may indicate aspects related to water quality and sediment. The lack of information about these communities in Brazilian aquatic environments, as well as the application of native species as bioindicators of lotic environmental, stimulated the conception of this paper. Thus, the aim was to study the community of aquatic Oligochaeta in selected stretches of the Juruena River (MT), thereby generating grounds for future environmental monitoring action in lotic ecosystems. For this purpose, samples were analyzed at bimonthly intervals during the period from January to November 2009, in stretches of the Juruena River (Amazon River Basin) located in the State of Mato Grosso (MT). Two methods were used to collect the organisms: a) "D" network in small clusters of fixed macrophytes in the sediment on the river banks; and b) Ekman-Birge dredge in fine sediment. Preliminary results were 584 organisms distributed in 22 taxa. Of these, 22 valid species were identified. This number corresponds to approximately 25% of the aquatic oligochaete species registered in Brazil. Of these species, Limnodrilus hoffmeisteri, Dero nivea and Pristina rosea can be associated with organic enrichment conditions and/or some level of environmental degradation.

Resumo: Comunidades de oligoquetos constituem importante componente em ambientes de água doce, onde sua abundância e composição podem indicar aspectos relacionados à qualidade da água e do sedimento. A carência de informações sobre estas comunidades em ambientes aquáticos brasileiros, bem como a aplicação de espécies nativas como bioindicadores de ambientes lóticos estimularam o desenvolvimento do presente trabalho. Assim, o objetivo foi estudar a comunidade de oligoquetos aquáticos em trechos selecionados do Rio Juruena (MT), gerando subsídios para futuras ações de monitoramento ambiental em ecossistemas lóticos. Métodos: Para isso foram analisadas amostras efetuadas em intervalos bimestrais durante o período de janeiro a novembro 2009, em trechos do Rio Juruena (Bacia Hidrográfica do Rio Amazonas) localizado no Estado de Mato Grosso (MT). Para coleta dos organismos foram utilizados dois métodos: a) rede em "D" em pequenos agrupamentos de macrófitas fixas no sedimento nas margens do rio; e b) draga Ekman-Birge em sedimento arenoso. Os resultados preliminares 584 organismos distribuídos em 22 táxons. Dentre estes, foram identificadas 22 espécies válidas. Esse número corresponde aproximadamente 25% das espécies de oligoquetos aquáticos registradas no Brasil. Destas espécies, Limnodrilus hoffmeisteri, Dero nivea e Pristina rosea podem ser associadas à condições de enriquecimento orgânico e/ou algum nível de degradação ambiental.

Aquatic oligochaeta (Annelida: Clitellata) in extractive reserve Lake Cuniã, Western Brazilian Amazon / Oligoquetos aquáticos (Annelida: Clitellata) na reserva extrativista Lago do Cuniã, Amazônia Ocidental Brasileira

Abstract Oligochaeta is one of the most common and abundant taxon in continental aquatic fauna. However, knowledge of their distribution in Brazilian ecosystems is still incomplete and fragmented. Thus, the aim of this study was to develop an inventory of aquatic oligochaetes in the Extractive Reserve of Lake Cuniã in the State of Rondônia, Brazil. Collections of data were performed during the dry (August 2015) and rainy seasons (February 2016). The sediment samples were collected near the lakeside region using the kick sampling method and a kick-net sampler (mesh size of 0.25mm). This paper provides a catalog with 12 taxon from a total of 383 specimens, distributed into two families: Naididae (95.08%) and Opistocystidae (4.92%). The Pristininae subfamily was the most significant (85.68%), followed by subfamilies: Naidinae (8.36%), Tubificinae (0.52%) and Rhyacondrilinae (0.52%). In addition, some species such as Allonais inaequalis, Aulophorus furcatus, Dero nivea, Pristina synclites, Pristina menoni and Opistocysta serrata, were recorded for the first time in the Brazilian Amazon region. Therefore, the results of this study contribute to increase knowledge on the distribution of the Oligochaeta class in Brazil, particularly in the North of the country, which is so extensive and rich in water resources, but not extensively studied.

Resumo Oligochaeta é um dos táxons mais comuns e abundantes na fauna aquática continental. No entanto, o conhecimento da sua distribuição nos ecossistemas brasileiros ainda é incompleto e fragmentado. Assim, o objetivo deste estudo foi desenvolver um inventário de oligoquetos aquáticos na Reserva Extrativista do Lago Cuniã no estado de Rondônia, Brasil. Foram realizadas duas coletas, cobrindo o período seco (agosto 2015) e chuvoso (fevereiro 2016). As amostras de sedimento foram coletadas perto da região marginal do lago pelo método de amostragem Kick sampling usando um amostrador Kick-net (malha de 0,25 mm). Nós catalogamos 12 táxons do total de 383 espécimes, distribuídos em duas famílias: Naididae (95,08%) e Opistocystidae (4,92%). A subfamília Pristininae foi a mais significativa (85,68%), seguida das subfamílias: Naidinae (8,36%), Tubificinae (0,52%) e Rhyacondrilinae (0,52%). Além disso, algumas espécies, como Allonais inaequalis, Aulophorus furcatus, Dero nivea, Pristina synclites, Pristina menoni e Opistocysta serrata, tiveram o primeiro registro na Amazônia brasileira. Assim, os resultados deste estudo contribuem para aumentar o conhecimento da distribuição da classe Oligochaeta no Brasil, particularmente no Norte do país, que é tão extenso e rico em recursos hídricos, porém pouco estudado.

First report of Epibiont ciliates (Ciliophora: Peritrichia) living on larvae of Leptophlebiidae (Ephemeroptera) from Brazil

ABSTRACT Epibiosis was understood as a commensalism relation between two or more organisms. However, some studies have shown that epibionts can cause deleterious effects to their host. Here, we reported the first report of epibiosis between protozoa Epibiont ciliates (Ciliophora: Peritrichia) living on larvae of Ephemeroptera from Brazil.

Aquatic Oligochaeta (Annelida: Clitellata) from State of São Paulo, Brazil: Diversity and Occurrence review / Oligochaeta aquático (Annelida: Clitellata) do Estado de São Paulo: Revisão da Diversidade e Ocorrência

More than 5.000 species are described to Class Oligochaeta, and approximately 1650 aquatic species are recognized around the world. Knowledge regarding abundance and composition of limnic oligochaetes can be used as an indicator of water and sediment quality. Thus, this paper aims to summarize all published data on aquatic Oligochaeta from State of São Paulo (Brazil), in order to establish a cheklist of microdrili from the State. The list emphasizes the diversity of limnic oligochaetes and provides a general overview of their distribution and also ecological aspects. Were examined the bibliographical data on São Paulo aquatic Oligochaeta, including species catalogs and taxonomic and ecological literature. Were analyzed a total of 34 academic researches, 32 journal papers and two taxonomic catalogs. This analysis resulted in a list of 75 valid species, distributed in 24 genera and five families. This amount of taxa corresponds to 4.5% of the aquatic Oligochaeta worldwide valid species, and about 87% of the Brazilian species.

Mais de 5.000 espécies são descritas para a Classe Oligochaeta e aproximadamente 1650 espécies aquáticas são reconhecidas em todo o mundo. O conhecimento sobre a composição e abundância de oligoquetos límnicos pode ser um indicador de qualidade da água e/ou sedimento. Assim, este trabalho teve como objetivo reunir todas as informações publicadas sobre Oligochaeta aquático do Estado de São Paulo (Brasil), a fim de estabelecer uma lista de táxons de microdrili registrados. A lista destaca a diversidade de oligoquetos límnicos e fornece uma visão geral de sua distribuição e aspectos ecológicos. Para isso, foram examinados dados bibliográficos de Oligochaeta aquáticos em São Paulo, incluindo catálogos de espécies, bem como artigos sobre taxonomia e de ecologia. Foram analisados ??o total de 34 trabalhos acadêmicos, sendo 32 artigos e dois catálogos taxonômicos. Esta análise resultou em uma lista de 75 espécies válidas, distribuídas em 24 gêneros e cinco famílias. Este montante corresponde a 4,5% das espécies de Oligochaeta aquático registradas no mundo, e aproximadamente 87 % das espécies brasileiras.

Description of diet of pelagic fish in the southwestern Atlantic, Brazil / Descrição da dieta de peixes pelágicos no Oceano Atlântico, Brasil

This study reveals the food composition of pelagic fishes living in the southwestern Atlantic Ocean. As such more common pelagic species are considered to be top predators, the study proposes to know what constitutes their main food. Fish are not commonly found within their stomach contents, but instead, cephalopods are their most common food. As can be observed, Teuthida cephalopods compose their principal diet. The stomach contents of specimens of Xiphias gladius, Thunnus albacares, T. obesus, T. alalunga, Isurus oxyrinchus and Alopias superciliosus caught during July 2007 to June 2009 by using tuna longliners were studied. Teuthida cephalopods constitute the main food item for the three tuna species, while X. gladius feeds mainly on Ommastrephidae cephalopods. Though the differences among the kinds of cephalopods exist, they constitute the principal resource these fish use to live at least in the southern Atlantic Ocean.

Este estudo descreve a composição da dieta de peixes pelágicos que vivem no Oceano Atlântico Sudoeste. Como tais espécies pelágicas são consideradas predadoras de topo, o estudo propõe conhecer o que constitui sua principal fonte de alimento. Peixes não são comumente encontrados em seus conteúdos estomacais, em vez disso, os cefalópodes são os alimentos mais comuns. Como pode ser observado, cefalópodes Teuthida compreendem sua dieta principal. O conteúdo estomacal de espécimes de Xiphias gladius, Thunnus albacares, T. obesus, T. alalunga, Isurus oxyrinchus e Alopias superciliosus, capturados durante julho de 2007 a junho de 2009 prela frota atuneira, foram estudados. Cefalópodes Teuthida constituem o principal item alimentar das três espécies de atum, enquanto X. gladius alimenta-se principalmente de cefalópodes Ommastrephidae. Embora as diferenças entre os tipos de cafalópodes existam, eles constituem o principal recurso que estes peixes usam para viver, pelo menos no Oceano Atlântico Sudoeste.

Oligochaeta (Annelida: Clitellata) em córregos de baixa ordem do Parque Estadual de Campos do Jordão (São Paulo - Brasil) / Oligochaeta (Annelida: Clitellata) in headwater streams of the Parque Estadual de Campos do Jordão (São Paulo - Brazil)

O objetivo desse artigo foi inventariar as espécies de oligoquetos limnícolas que habitam córregos do Parque Estadual de Campos do Jordão (PECJ). As amostras revelaram 2302 indivíduos, distribuídos em três famílias (Naididae, Enchytraeidae, Tubificidae). Foram inventariadas 17 espécies, sendo elas: Achaeta sp., Allonais paraguayensis, Chaetogaster diastrophus, Nais communis, Nais variabilis, Pristina biserrata, Pristina leidyi, Pristina proboscidea, Pristinella jenkinae, Pristinella longidentata, Pristinella minuta, Pristinella notopora, Pristinella osborni, Pristinella sima, Aulodrilus limnobius, Botrioneurum sp. e Limnodrilus hoffmeisteri. O número total de espécies encontrado representa 24 por cento de todas as espécies de oligoquetos registrados em diversos ambientes aquáticos no Brasil (70), evidenciando a importância deste trabalho, visto que há ainda grandes lacunas no conhecimento da fauna de oligoquetos límnicos no Brasil.

This study inventoried stream oligochaetes of the Campos do Jordão State Park (CJSP), São Paulo, Brazil. A total of 2302 individuals of three families (Naididae, Enchytraeidae, Turbificidae) were obtained. Seventeen species were inventoried: Achaeta sp., Allonais paraguayensis, Chaetogaster diastrophus, Nais communis, Nais variabilis, Pristina biserrata, Pristina leidyi, Pristina proboscidea, Pristinella jenkinae, Pristinella longidentata, Pristinella minuta, Pristinella notopora, Pristinella osborni, Pristinella sima, Aulodrilus limnobius, Bothrioneurum sp., and Limnodrilus hoffmeisteri. The total number of species found represents 24 percent of all oligochaetes species (70) recorded in diverse aquatic environments in Brazil, making this inventory very important given the poor knowledge of this group in Brazil.