Ionic balance of water and physical-chemical properties of soil from marine shrimp farms of the Jaguaruna interior county, Ceará, Brazil / Balanço iônico da água e características físico-químicas do solo de fazendas de camarão marinho do município interiorano de Jaguaruana, Ceará, Brasil

The present work aimed at describing and characterizing the physical-chemical composition and the Na+: K+ and Ca+2: Mg+2 ratios of well waters used to fill L. vannamei culture ponds, belonging to farms located in Jaguaruana, an interior municipality of the State of Ceará, Brazil. Besides that, the study also sought to describe and characterize the physical-chemical properties of soils from the same shrimp farms. Well water and soil samples were taken in four farms, three located in Jaguaruana (Pasta Branca, Sargento and Poró) and one in the municipality of Aracati, which served as a control. Water samples were analyzed for pH, specific conductance, salinity, total alkalinity, total and calcium hardness, potassium and sodium. Soil samples were analyzed for pH, specific conductance, salinity, potential acidity, phosphorus, organic carbon, total nitrogen, sodium and potassium. The well waters from Aracati, Pasta Branca/Sargento and Poró were classified as euhaline, oligohaline and mesohaline, respectively. The results of pH indicated that liming was necessary in all four farms. All well waters demanded potassium fertilization to compensate for K+ deficiency and to adjust Na: K ratio. It has been concluded that, in the productive management of inland shrimp farms, it is important to monitor not only the Na: K and Ca: Mg ratios of the water, but also the absolute concentrations of each ion.

O presente trabalho teve os seguintes objetivos: 1 - caracterizar a composição físico-química e as relações Na+: K+ e Ca+2: Mg+2 da água de poços profundos utilizados no abastecimento de viveiros de criação de camarão marinho, Litopenaeus vannamei, pertencentes a fazendas do município interiorano de Jaguaruana, Ceará, Brasil; 2 - caracterizar a composição físico-químico do solo das fazendas de camarão de Jaguaruana. Amostras de água e solo foram coletadas em quatro fazendas, três localizadas em Jaguaruana (Pasta Branca, Sargento e Poró) e uma em Aracati, que serviu como controle experimental. As amostras de água foram analisadas para pH, condutividade elétrica, salinidade, clorinidade, alcalinidade total, dureza total e cálcica, potássio e sódio. As amostras de solo foram analisadas quanto ao pH, condutividade elétrica, salinidade, acidez potencial, fósforo, carbono orgânico, nitrogênio total, sódio e potássio. As águas das fazendas de Aracati, Pasta Branca/Sargento e Poró foram classificadas como eurihalina, oligohalinas e mesohalinas, respectivamente. Os resultados de pH da água (6,8 ± 0,2) indicaram a necessidade de calagem em todas as fazendas investigadas. A água de todos os poços demandava a fertilização potássica, tanto para suprir suas concentrações insuficientes, como para ajustar a relação Na: K. Concluiu-se que, no manejo produtivo de fazendas de carcinicultura interior, é importante monitorar não apenas as relações Na: K e Ca: Mg da água, mas também as concentrações absolutas de cada íon.

Ionic balance of water and physical-chemical properties of soil from marine shrimp farms of the Jaguaruna interior county, Ceará, Brazil / Balanço iônico da água e características físico-químicas do solo de fazendas de camarão marinho do município interiorano de Jaguaruana, Ceará, Brasil

The present work aimed at describing and characterizing the physical-chemical composition and the Na+: K+ and Ca+2: Mg+2 ratios of well waters used to fill L. vannamei culture ponds, belonging to farms located in Jaguaruana, an interior municipality of the State of Ceará, Brazil. Besides that, the study also sought to describe and characterize the physical-chemical properties of soils from the same shrimp farms. Well water and soil samples were taken in four farms, three located in Jaguaruana (Pasta Branca, Sargento and Poró) and one in the municipality of Aracati, which served as a control. Water samples were analyzed for pH, specific conductance, salinity, total alkalinity, total and calcium hardness, potassium and sodium. Soil samples were analyzed for pH, specific conductance, salinity, potential acidity, phosphorus, organic carbon, total nitrogen, sodium and potassium. The well waters from Aracati, Pasta Branca/Sargento and Poró were classified as euhaline, oligohaline and mesohaline, respectively. The results of pH indicated that liming was necessary in all four farms. All well waters demanded potassium fertilization to compensate for K+ deficiency and to adjust Na: K ratio. It has been concluded that, in the productive management of inland shrimp farms, it is important to monitor not only the Na: K and Ca: Mg ratios of the water, but also the absolute concentrations of each ion.(AU)

O presente trabalho teve os seguintes objetivos: 1 - caracterizar a composição físico-química e as relações Na+: K+ e Ca+2: Mg+2 da água de poços profundos utilizados no abastecimento de viveiros de criação de camarão marinho, Litopenaeus vannamei, pertencentes a fazendas do município interiorano de Jaguaruana, Ceará, Brasil; 2 - caracterizar a composição físico-químico do solo das fazendas de camarão de Jaguaruana. Amostras de água e solo foram coletadas em quatro fazendas, três localizadas em Jaguaruana (Pasta Branca, Sargento e Poró) e uma em Aracati, que serviu como controle experimental. As amostras de água foram analisadas para pH, condutividade elétrica, salinidade, clorinidade, alcalinidade total, dureza total e cálcica, potássio e sódio. As amostras de solo foram analisadas quanto ao pH, condutividade elétrica, salinidade, acidez potencial, fósforo, carbono orgânico, nitrogênio total, sódio e potássio. As águas das fazendas de Aracati, Pasta Branca/Sargento e Poró foram classificadas como eurihalina, oligohalinas e mesohalinas, respectivamente. Os resultados de pH da água (6,8 ± 0,2) indicaram a necessidade de calagem em todas as fazendas investigadas. A água de todos os poços demandava a fertilização potássica, tanto para suprir suas concentrações insuficientes, como para ajustar a relação Na: K. Concluiu-se que, no manejo produtivo de fazendas de carcinicultura interior, é importante monitorar não apenas as relações Na: K e Ca: Mg da água, mas também as concentrações absolutas de cada íon.(AU)

APRIMORAMENTO DO CULTIVO DO CAMARÃO MARINHO Litopenaeus vannamei EM ÁGUAS OLIGOHALINAS DOMINADAS POR BIOFLOCOS

A produção de L. vannamei em águas oligohalinas interiores (AOI) no Brasil está concentrada na região Nordeste, onde a composição iônica da água é considerada na escolha de áreas de cultivo e no gerenciamento dos recursos hídricos escassos na região. Águas interiores e marinhas apresentam composições distintas, podendo afetar processos fisiológicos de camarões marinhos e a produtividade dos cultivos, principalmente nas fases iniciais onde ocorre a aclimatação dos animais às condições das águas interiores. A correção constante da alcalinidade requer a utilização de compostos alcalinizantes adequados às condições dos sistemas de produção. No capítulo I foi realizado um levantamento bibliográfico acerca do cultivo de L. vannamei em AOIs e foi demonstrada a aplicabilidade de sistemas de cultivo fechados como forma de reduzir as demandas de água em regiões semiáridas, aumentar as produtividades dos cultivos e promover o desenvolvimento socioeconômico dessas regiões. O capítulo II avaliou as características da produção de L. vannamei em AOIs no Nordeste brasileiro, no intuito de direcionar a prospecção de novas áreas. Os dados foram coletados nos estados do Ceará, Rio Grande do Norte e Paraíba, totalizando 28 fazendas. As amostras de água foram classificadas por salinidade segundo o Sistema Veneza, em águas doces, oligohalinas e mesohalinas e as composições iônicas e os dados produtivos das propriedades comparados. Através da salinidade, condutividade elétrica (CE) e composição iônica, foram avaliados os usos das águas para irrigação e consumo humano. A maioria das propriedades foram fornecidas com águas oligohalinas e mesohalinas de rios ou poços, onde 78% delas foram consideradas impróprias para irrigação. A área média dos viveiros foi de 1,30 ± 1,08 ha. As amostras quando comparadas a água do mar diluída, demonstraram que o Na+ e SO4 2-, estavam em menor proporção (%), enquanto que o Mg2+, Ca2+ e o HCO3- estavam em maior proporção, independente da classe salina. As relações iônicas, Mg2+:Ca2+ e K+:Ca2+ estavam abaixo das ideais em todas as classes, enquanto que a Na+:K+ nas águas oligohalinas estavam em média adequadas para a espécie. Águas oligohalinas e mesohalinas são mais favoráveis a carcinocultura, por possuírem menos usos. Além disso, essas águas possuem alcalinidades e durezas totais superiores a águas doces podendo nelas serem alcançadas maiores produtividades. Através dos dados do capítulo II foi formulada uma salga artificial representativa das fazendas investigadas, chamada de Composição Iônica de Baixa Salinidade (CIBS). Nos capítulos III e IV antes dos xv experimentos as águas com a CIBS foram fertilizadas com NH4Cl para desenvolver um inóculo bacteriano. Os experimentos foram realizados na fase de berçário em meio oligohalino dominado por bioflocos. As pós-larvas foram alimentadas com dietas comerciais. Monitoraram-se a temperatura da água, pH, oxigênio dissolvido, compostos nitrogenados (N-AT, N-NO2- e N-NO3 -), ortofosfato, alcalinidade total (AT), dureza total (DT), salinidade, CE, sólidos suspensos totais e a concentração dos íons majoritários. O desempenho zootécnico foi avaliado através do peso médio final, sobrevivência, taxa de crescimento específico, ganho de peso semanal, produtividade e conversão alimentar aparente. O capítulo III utilizou a inoculação de águas marinhas para a correção iônica da água com a CIBS. O estudo durou 27 dias onde foram utilizados 20 tanques de 150L úteis, com 150 pós-larvas de 0,06g cada. Foram testados quatro tratamentos com inoculação (3, 6, 10 e 13%) e um tratamento sem (0%), com quatro repetições cada. Entre os compostos nitrogenados apenas o N-NO3 - atingiu concentrações acima do seguro em todos os tratamentos. O desempenho zootécnico foi superior nos tratamentos inoculados, não diferindo entre si. Os resultados estão associados ao incremento dos íons Na+, Mg2+ e K+ e da relação Na+:K+. Foi observado que 3% do inóculo marinho pode mitigar os efeitos negativos de desequilíbrios iônicos de águas oligohalinas no desenvolvimento de PLs de L. vannamei. O capítulo IV avaliou os efeitos da alcalinidade e do alcalinizante utilizado, na composição iônica da água e no desempenho zootécnico de L. vannamei. O estudo durou 40 dias e foi desenvolvido em águas com a CIBS com 0,5% de uma salmoura marinha. Os tratamentos testaram a cal hidratada ou o bicarbonato de sódio (NaHCO3 -) na manutenção das AT de 75, 150 e 300 mg de CaCO3 L-1, com três repetições cada, para isso foram utilizados 18 tanques de 50 litros povoados com 60 pós-larvas de L. vannamei com peso médio de 0,02g. Entre os compostos nitrogenados, apenas o NNO3 - atingiu valores inadequados em todos os tratamentos. A DT e Mg2+ foram maiores onde a AT de 300 mg CaCO3 L-1 de foi mantida com cal hidratada (Ca300), bem como a sobrevivência dos animais e a produtividade do sistema. A utilização de cal hidratada na maior concentração elevou além da AT a DT, protegendo os animais dos efeitos tóxicos do N-NO3 -, compensando a remoção do Ca2+ da água pelos animais durante a muda e assim gerando condições adequadas para o desenvolvimento de L. vannamei na fase de berçário em meio oligohalino dominado por bioflocos.

The L. vannamei production in inland oligohaline waters (IOW) in Brazil is concentrated in the Northeast region, where the ionic composition of water is considered in the selection of cultivation areas and the management of water resources scarce in the region. Inland and marine waters present distinct ionic concentrations, which may affect the physiological processes of marine shrimps and the productivity of crops, especially in the initial phases where the acclimatization of animals to inland water conditions occurs. The constant correction of alkalinity requires the use of alkalinizing compounds adequate to the conditions of the production systems. In Chapter I, a bibliographic survey on the cultivation of L. vannamei in IOWs was conducted and the applicability of closed cultivation systems was demonstrated as a way to reduce water demands in semiarid regions, increase productivities and promote the socioeconomic development of these regions. Chapter II evaluated the characteristics of L. vannamei production in IOWs in Northeastern Brazil in order to direct the prospecting of new areas. Data were collected in the states of Ceará, Rio Grande do Norte and Paraíba, totaling 28 shrimp farms. The water samples were classified by salinity according to the Venice System, in freshwater, oligohaline and mesohaline and the ionic compositions and the production data of the shrimp farms compared. Through salinity, electrical conductivity (EC) and ionic composition, the uses of water for irrigation and human consumption were evaluated. Most of the properties were supplied with oligohaline and mesohaline waters from rivers or wells, where 78% of them were considered unsuitable for irrigation. The average ponds area was 1.30 ± 1.08 ha. The samples when compared to diluted sea water, showed that Na+ and SO4 2- were in a lower proportion (%), while Mg2+, Ca2+ and HCO3 - were in a higher proportion, independent of the saline class. The ionic ratios, Mg2+:Ca2+ and K+:Ca2+ were below ideal in all classes, while Na+:K+ in oligohaline waters were on average adequate for the species. Oligohaline and mesohaline waters are more favorable for shrimp culture, as they have less uses. In addition, these waters have alkalinities and total hardness superior to freshwaters and higher productivity can be achieved in them. Through the data of Chapter II, an artificial salting representative of the farms investigated was formulated, called Low Salinity Ionic Composition (LSIC). In chapters III and IV before the experiments, the water with the LSIC was fertilized with NH4Cl to develop a bacterial inoculum. The experiments were performed in the nursery phase in xvii an oligohaline medium dominated by bioflocs. The post-larvae were fed commercial diets. Water temperature (T°C), pH, dissolved oxygen (DO), nitrogenous compounds (NAT, N-NO2 - and N-NO3 -), orthophosphate, total alkalinity (TA), total hardness (TH), salinity, EC, total suspended solids, and the concentration of major ions were monitored. Zootechnical performance was evaluated by mean final weight,survival, specific growth rate, weekly weight gain, productivity and apparent feed conversion. Chapter III used marine water inoculation for ionic water correction with LSIC. The study lasted 27 days where 20 tanks of 150L were used, with 150 post-larvae of 0.06g each. Four treatments were tested with inoculation (3, 6, 10 and 13%) and one treatment without (0%), with four repetitions each. Among the nitrogen compounds only N-NO3- reached above safe concentrations in all treatments. The zootechnical performance was superior in the inoculated treatments, not differing from each other. The results are associated with the increase of Na+, Mg2+ and K+ ions and the Na+:K+ ratio. It was observed that 3% of the inoculum can mitigate the negative effects of ion imbalances of oligohaline waters on the development of PLs of L. vannamei. Chapter IV evaluated the effects of alkalinity and the alkalinizing compound used, on the ionic composition of the water and on the zootechnical performance of L. vannamei. The study lasted 40 days and was developed in waters with LSIC with 0.5% of a marine brine. The treatments tested hydrated lime or sodium bicarbonate (NaHCO3-) in the maintenance of 75, 150 and 300 mg of CaCO3 L-1 alkalinities, with three repetitions each, 18 tanks of 50 L populated with 60 post-larvae of L. vannamei with an average weight of 0.02g were used. Among the nitrogen compounds only N-NO3 - reached inadequate values in all treatments. The TH and Mg2+ were higher where the total alkalinity of 300 mg of CaCO3 L-1 was maintained with hydrated lime (Ca300), as well as the survival of the animals and the productivity of the system. The use of hydrated lime in the higher concentration elevated the alkalinity beyond total hardness, protecting the animals from the toxic effects of N-NO3 -, compensating the removal of Ca2+ from the water by the animals during moulting and thus generating adequate conditions for the development of L. vannamei in the nursery phase in an oligohaline environment dominated by bioflocs.

New record of Akashiwo sanguinea (Dinophyta) in the tropical estuarine waters of Northeastern Brazil (Western Atlantic) / Novo registro de Akashiwo sanguinea (Dinophyta) em águas estuarinas tropicais do nordeste do Brasil (Atlântico Ocidental)

This study reports the occurrence and the effect of the environmental factors on the spatial and temporal distribution of the dinoflagellate Akashiwo sanguinea (Hirasaka) Hansen & Moestrup in estuarine waters of northeastern Brazil. Samples were collected at seven stations from March 2007 to February 2008 during high tide and low tide, using Van Dorn bottles. The samples were immediately fixed with Lugol and analyzed with the Utermõhl method. Water samples were also collected for the identification of the hydrological characteristics of the area. Akashiwo sanguinea occurred throughout the annual cycle and at all sampling sites with densities ranging between 5 and 410 x 103 cells.L–1. The highest densities were recorded at low tide, especially during the months of the rainy season (July: 210 x 103 cells.L–1; August: 410 x 103 cells.L–1). Density values were within the normal range and blooms were not detected. Despite being common in the area, the species showed preference for sites with high concentrations of orthophosphate and total dissolved phosphorus and with salinity in the mesohaline regime.(AU)

Este estudo relata a ocorrência e o efeito dos fatores ambientais na distribuição espacial e temporal do dinoflagelado Akashiwo sanguinea (Hirasaka) Hansen et Moestrup em águas estuarinas do Nordeste do Brasil. As amostras foram coletadas em sete estações, durante o período de março 2007 a fevereiro 2008 durante os regimes de preamar e baixa-mar, com o auxílio de garrafas tipo Van Dorn. As amostras foram imediatamente fixadas com lugol e analisadas pelo método de Utermõhl. Amostras de água foram também coletadas para a identificação das características hidrológicas da área. Akashiwo sanguinea ocorreu em todo o ciclo anual e em todos os locais de coleta com densidade variando de 5 a 410 cells.L–1 x 103, sendo as maiores densidades registradas na baixa-mar, principalmente, durante os meses do período chuvoso (julho 210 cells.L–1 x 103, agosto 410 cells.L–1 x 103). Os valores quantitativos estiveram dentro dos padrões normais, não tendo sido detectados florescimentos com conotações de blooms. Apesar de ser frequente na área, a espécie mostrou preferência pelos locais com maiores concentrações de ortofosfato dissolvido e fósforo total dissolvido e salinidade compreendida no regime mesoalino.(AU)

Zooplankton of an urban coastal lagoon: composition and association with environmental factors and summer fish kill

Zooplankton may be regarded as a sensitive tool for monitoring environmental variations in coastal lagoons due to their ability to immediately react to changes in the water column trophic features and salinity levels. As a coastal lagoon with a broad history of anthropic influence, Rodrigo de Freitas Lagoon (Rio de Janeiro, Brazil) is widely used for water sports and artisanal fishing. The present study aimed to expand the knowledge base about zooplankton in the Rodrigo de Freitas Lagoon by assessing the composition and time-spatial distribution of the major zooplankton groups. Samples were collected fortnightly from at four distinct sampling points August 2001 to July 2002. At each point, salinity, temperature, dissolved oxygen and water transparency were measured. During the study period, the lagoon behaved as an spatially homogeneous environment in what regards the abiotic variables. However, all these variables showed significant differences along the time, mainly related to seasonality (air temperature and rainy and dry periods). The zooplankton community showed low taxonomic richness, with the predominance of species commonly found in coastal lagoons, especially with mesohaline conditions, as well as those found in estuaries. An interesting fact was the rise in zooplankton abundance at all sampling points right after a fish kill event. Such increase was caused mainly by the Brachionus plicatilis O.F. Müller 1786 species. Thus, the zooplankton community was affected by physical and chemical factors, mainly by the dissolved oxygen decline event and variations in the influx of seawater into the lagoon. In addition, phytoplankton availability and fish predation pressure were suggested as important regulating factors of the zooplankton community.

Zooplankton of an urban coastal lagoon: composition and association with environmental factors and summer fish kill

Zooplankton may be regarded as a sensitive tool for monitoring environmental variations in coastal lagoons due to their ability to immediately react to changes in the water column trophic features and salinity levels. As a coastal lagoon with a broad history of anthropic influence, Rodrigo de Freitas Lagoon (Rio de Janeiro, Brazil) is widely used for water sports and artisanal fishing. The present study aimed to expand the knowledge base about zooplankton in the Rodrigo de Freitas Lagoon by assessing the composition and time-spatial distribution of the major zooplankton groups. Samples were collected fortnightly from at four distinct sampling points August 2001 to July 2002. At each point, salinity, temperature, dissolved oxygen and water transparency were measured. During the study period, the lagoon behaved as an spatially homogeneous environment in what regards the abiotic variables. However, all these variables showed significant differences along the time, mainly related to seasonality (air temperature and rainy and dry periods). The zooplankton community showed low taxonomic richness, with the predominance of species commonly found in coastal lagoons, especially with mesohaline conditions, as well as those found in estuaries. An interesting fact was the rise in zooplankton abundance at all sampling points right after a fish kill event. Such increase was caused mainly by the Brachionus plicatilis O.F. Müller 1786 species. Thus, the zooplankton community was affected by physical and chemical factors, mainly by the dissolved oxygen decline event and variations in the influx of seawater into the lagoon. In addition, phytoplankton availability and fish predation pressure were suggested as important regulating factors of the zooplankton community.

Zooplankton of an urban coastal lagoon: composition and association with environmental factors and summer fish kill

Zooplankton may be regarded as a sensitive tool for monitoring environmental variations in coastal lagoons due to their ability to immediately react to changes in the water column trophic features and salinity levels. As a coastal lagoon with a broad history of anthropic influence, Rodrigo de Freitas Lagoon (Rio de Janeiro, Brazil) is widely used for water sports and artisanal fishing. The present study aimed to expand the knowledge base about zooplankton in the Rodrigo de Freitas Lagoon by assessing the composition and time-spatial distribution of the major zooplankton groups. Samples were collected fortnightly from at four distinct sampling points August 2001 to July 2002. At each point, salinity, temperature, dissolved oxygen and water transparency were measured. During the study period, the lagoon behaved as an spatially homogeneous environment in what regards the abiotic variables. However, all these variables showed significant differences along the time, mainly related to seasonality (air temperature and rainy and dry periods). The zooplankton community showed low taxonomic richness, with the predominance of species commonly found in coastal lagoons, especially with mesohaline conditions, as well as those found in estuaries. An interesting fact was the rise in zooplankton abundance at all sampling points right after a fish kill event. Such increase was caused mainly by the Brachionus plicatilis O.F. Müller 1786 species. Thus, the zooplankton community was affected by physical and chemical factors, mainly by the dissolved oxygen decline event and variations in the influx of seawater into the lagoon. In addition, phytoplankton availability and fish predation pressure were suggested as important regulating factors of the zooplankton community.

Spatial distribution of the estuarine ichthyofauna of the Rio Formoso (Pernambuco, Brazil), with emphasis on reef fish

The objectives of the present study were to identify species of reef fish that use the Rio Formoso estuary (northeastern Brazil) as a refuge and natural nursery and to describe the spatial distribution of the estuary fish fauna in rainy and dry seasons. A total of 5475 specimens, across 78 species and 39 families, were analyzed; 51.3% of the species were of reef origin. Among these, Eucinostomus melanopterus (Bleeker, 1863), E. gula (Cuvier, 1830), and Sphoeroides testudineus (Linnaeus, 1758), in this order, were the most abundant in the upper estuary; S. greeleyi Gilbert, 1900, E. melanopterus, and Lutjanus synagris (Linnaeus, 1758) were the most abundant in the mid estuary; and E. gula and Albula vulpes (Linnaeus, 1758) in the lower estuary. The percentages of reef species were 39.2%, 54.2% and 66.7% for the upper, mid and lower regions, respectively. The greatest diversity was found in the upper estuary and greatest abundance occurred in the mid region. The type of sediment was a strong determinant of the spatial distribution of fish fauna. The most abundant species were found in a mesohaline (5-18) to euhaline (30-40) salinity regimen, suggesting some capacity for osmotic regulation. The fish fauna of the Rio Formoso estuary receives a direct influence from the reefs and coastal region between Sirinhaém and Tamandaré, thereby providing a greater richness of reef fish.

Spatial distribution of the estuarine ichthyofauna of the Rio Formoso (Pernambuco, Brazil), with emphasis on reef fish

The objectives of the present study were to identify species of reef fish that use the Rio Formoso estuary (northeastern Brazil) as a refuge and natural nursery and to describe the spatial distribution of the estuary fish fauna in rainy and dry seasons. A total of 5475 specimens, across 78 species and 39 families, were analyzed; 51.3% of the species were of reef origin. Among these, Eucinostomus melanopterus (Bleeker, 1863), E. gula (Cuvier, 1830), and Sphoeroides testudineus (Linnaeus, 1758), in this order, were the most abundant in the upper estuary; S. greeleyi Gilbert, 1900, E. melanopterus, and Lutjanus synagris (Linnaeus, 1758) were the most abundant in the mid estuary; and E. gula and Albula vulpes (Linnaeus, 1758) in the lower estuary. The percentages of reef species were 39.2%, 54.2% and 66.7% for the upper, mid and lower regions, respectively. The greatest diversity was found in the upper estuary and greatest abundance occurred in the mid region. The type of sediment was a strong determinant of the spatial distribution of fish fauna. The most abundant species were found in a mesohaline (5-18) to euhaline (30-40) salinity regimen, suggesting some capacity for osmotic regulation. The fish fauna of the Rio Formoso estuary receives a direct influence from the reefs and coastal region between Sirinhaém and Tamandaré, thereby providing a greater richness of reef fish.

Spatial distribution of the estuarine ichthyofauna of the Rio Formoso (Pernambuco, Brazil), with emphasis on reef fish

The objectives of the present study were to identify species of reef fish that use the Rio Formoso estuary (northeastern Brazil) as a refuge and natural nursery and to describe the spatial distribution of the estuary fish fauna in rainy and dry seasons. A total of 5475 specimens, across 78 species and 39 families, were analyzed; 51.3% of the species were of reef origin. Among these, Eucinostomus melanopterus (Bleeker, 1863), E. gula (Cuvier, 1830), and Sphoeroides testudineus (Linnaeus, 1758), in this order, were the most abundant in the upper estuary; S. greeleyi Gilbert, 1900, E. melanopterus, and Lutjanus synagris (Linnaeus, 1758) were the most abundant in the mid estuary; and E. gula and Albula vulpes (Linnaeus, 1758) in the lower estuary. The percentages of reef species were 39.2%, 54.2% and 66.7% for the upper, mid and lower regions, respectively. The greatest diversity was found in the upper estuary and greatest abundance occurred in the mid region. The type of sediment was a strong determinant of the spatial distribution of fish fauna. The most abundant species were found in a mesohaline (5-18) to euhaline (30-40) salinity regimen, suggesting some capacity for osmotic regulation. The fish fauna of the Rio Formoso estuary receives a direct influence from the reefs and coastal region between Sirinhaém and Tamandaré, thereby providing a greater richness of reef fish.

Environmental changes and zooplankton temporal and spatial variation in a disturbed brazilian coastal lagoon

The Imboassica lagoon, located in the Municipality of Macaé (RJ), is separated from the sea by a sand bar, and its surroundings are partially occupied by residential areas. This coastal lagoon has undergone environmental degradation due to sewage input and artificial sand bar openings. The temporal and spatial variation of environmental variables and zooplankton were studied monthly for four years. There were five artificial openings of the sand bar during the period of study, mostly in the rainy season. Besides osmotic changes, these events caused the drainage of the water of the lagoon into the sea, loss of total organic nitrogen, and an increase of total phosphorus. The zooplankton community of Imboassica lagoon included freshwater and marine taxa, holoplanktonic, meroplanktonic and nectobenthonic forms. Polychaeta, Bivalvia and Gastropoda larvae, and the taxa of Rotifera Hexarthra spp., Lecane bulla, Synchaeta bicornis, nauplii of Cyclopoida and Calanoida copepods were considered constant taxa. Distinct zooplankton assemblages were found during zooplankton spatial surveys in oligohaline and mesohaline conditions. The successful zooplankton populations were either favored by the disturbance of the sand bar opening, such as the veligers of the gastropod Heleobia australis, or capable of fast recovery after the closing of the sand bar, during the succession from a marine into an oligohaline environment, such as Hexarthra spp.. Such populations seemed well adapted to the stress conditions usually found in the lagoon due to osmotic changes, column mixing, nutrient input, and high fish predation pressure. Rare species in the community, such as Moina minuta, presented population increases all over the lagoon under oligohaline conditions.

A Lagoa Imboassica, localizada no Município de Macaé (RJ), é separada do mar por uma barra de areia e se encontra cercada parcialmente por áreas residenciais. Esta lagoa costeira tem sofrido intensa degradação ambiental devido à afluência de esgotos domésticos e a aberturas artificiais da barra de areia. Neste estudo foram acompanhadas, mensalmente ao longo de quatro anos, as variações temporais e espaciais de variáveis ambientais e do zooplâncton. Durante o período estudado foram realizadas cinco aberturas artificiais da barra de areia, sendo a maioria efetuada na época chuvosa. Além das alterações osmóticas, estas aberturas causaram a drenagem da água da lagoa para o mar, diminuição dos valores de nitrogênio total e aumento da concentração de fósforo total. A comunidade zooplanctônica da lagoa incluiu táxons de água doce e marinhos e formas holoplanctônicas, meroplanctônicas e nectobentônicas. Foram considerados constantes na comunidade larvas de Polychaeta, Bivalvia e Gastropoda, os táxons de Rotifera Hexarthra spp., Lecane bulla, Synchaeta bicornis e naúplios de copépodos Cyclopoida e Calanoida. Durante as amostragens espaciais ao longo de todo o corpo da lagoa em condições oligohalinas e mesohalinas foram encontradas distintas assembléias zooplanctônicas. As populações zooplanctônicas que apresentaram maior ocorrência foram aquelas aparentemente favorecidas pelo distúrbio causado pelas aberturas de barra, tais como véligers do gastrópode Heleobia australis, ou capazes de recuperação rápida após o fechamento da barra de areia, durante a transição de um ambiente marinho para um oligohalino, como Hexarthra spp.. Tais populações se mostraram bem adaptadas às condições de "stress" usualmente encontradas na lagoa devido a mudanças osmóticas, mistura da coluna d'água, aporte contínuo de nutrientes e alta pressão de predação por peixes. As espécies consideradas como raras na comunidade zooplanctônica, como Moina minuta apresentaram maiores densidades ao longo de toda a lagoa em condições oligohalinas.

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.

Levantamentos para detecção de esponjas dulcícolas foram conduzidos em diversos corpos d'água da faixa arenosa costeira, de norte a sul, particularmente no Brasil. Os resultados permitiram a distinção de quatro ambientes específicos em relação à presença de certas espécies, considerando-se como fator determinante a ocorrência recorrente, exclusiva ou preponderante de uma espécie nos tipos de habitats examinados. O primeiro grupo é o de habitats mesohalinos de lagunas, nas faixas tropical e subtropical, indicado por Spongilla alba Carter, 1849. O segundo é constituído por lagoas rasas, entre dunas, situado na faixa tropical, com a presença de Corvoheteromeyenia heterosclera (Ezcurra de Drago, 1974). O terceiro é o de lagoas/banhados, também rasos, vizinhos ao cordão de dunas, na região temperada, com Racekiela sheilae (Volkmer-Ribeiro, De Rosa-Barbosa & Tavares, 1988). O quarto é constituído por ambientes organicamente enriquecidos, nas áreas marginais de lagunas e proximidades de barras de pequenos rios, evoluindo para lagoas e banhados em processos de colmatação, com fundos lodosos, não distantes da borda oceânica, com a presença quase exclusiva de Ephydatia facunda Weltner, 1895. Essas espécies são por isto propostas como indicadoras de tais habitats, promovendo-se a ampliação de suas descrições e a caracterização sintética desses ambientes. É proposta chave para identificação baseada nas espículas dessas esponjas. Os resultados apresentados visam contribuir para a identificação de suas espículas em colunas de sedimentos recuperados em áreas costeiras do Brasil e da América do Sul. As determinações de paleobordas oceânicas integram estudos com alto grau de interesse no que respeita a projeções temporais e flutuações de níveis ascendentes/regressivos dos oceanos.

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.

Levantamentos para detecção de esponjas dulcícolas foram conduzidos em diversos corpos d'água da faixa arenosa costeira, de norte a sul, particularmente no Brasil. Os resultados permitiram a distinção de quatro ambientes específicos em relação à presença de certas espécies, considerando-se como fator determinante a ocorrência recorrente, exclusiva ou preponderante de uma espécie nos tipos de habitats examinados. O primeiro grupo é o de habitats mesohalinos de lagunas, nas faixas tropical e subtropical, indicado por Spongilla alba Carter, 1849. O segundo é constituído por lagoas rasas, entre dunas, situado na faixa tropical, com a presença de Corvoheteromeyenia heterosclera (Ezcurra de Drago, 1974). O terceiro é o de lagoas/banhados, também rasos, vizinhos ao cordão de dunas, na região temperada, com Racekiela sheilae (Volkmer-Ribeiro, De Rosa-Barbosa & Tavares, 1988). O quarto é constituído por ambientes organicamente enriquecidos, nas áreas marginais de lagunas e proximidades de barras de pequenos rios, evoluindo para lagoas e banhados em processos de colmatação, com fundos lodosos, não distantes da borda oceânica, com a presença quase exclusiva de Ephydatia facunda Weltner, 1895. Essas espécies são por isto propostas como indicadoras de tais habitats, promovendo-se a ampliação de suas descrições e a caracterização sintética desses ambientes. É proposta chave para identificação baseada nas espículas dessas esponjas. Os resultados apresentados visam contribuir para a identificação de suas espículas em colunas de sedimentos recuperados em áreas costeiras do Brasil e da América do Sul. As determinações de paleobordas oceânicas integram estudos com alto grau de interesse no que respeita a projeções temporais e flutuações de níveis ascendentes/regressivos dos oceanos.