RESUMO

Phenanthnere (PHE) is a polycyclic aromatic hydrocarbon continuously discarded in the marine environment and bioavailable to many aquatic species. Although studies about PHE toxicity have been documented for adult oysters, the effects on early developmental stages are poorly characterized in bivalves. In this study, the effects of PHE (0.02 and 2.0µg.L-1) were evaluated on the embryogenesis and larval development of Crassostrea gigas. Toxicity bioassays, growth and deformities assessment, analysis of shell calcium abundance and transcript levels of genes related to xenobiotic biotransformation (CYP2AU2, CYP30C1), immune system (Cg-Tal) and tissue growth and shell formation (Ferritin, Insulin-like, Cg-Try, Calmodulin and Nacrein) were assayed in D-shape larvae after 24h of PHE exposure. At the highest concentration (2.0µg.L-1), PHE decreased the frequency of normal development (19.7±2.9%) and shell size (53.5±2.8mm). Developmental deformities were mostly related to abnormal mantle and shell formation. Lower calcium levels in oyster shells exposed to PHE 2.0µg.L-1 were observed, suggesting effects on shell structure. At this same PHE concentration, CYP30C1, Cg-Tal, Cg-Tyr, Calmodulin were upregulated and CYP2AU2, Ferritin, Nacrein, and Insulin-Like were downregulated compared to control larvae. At the lowest PHE concentration (0.02µg.L-1), it was observed a minor decrease in normal larval development (89,6±6%) and the remaining parameters were not affected. This is the first study to provide evidences that exposure to PHE can affect early oyster development at the molecular and morphological levels, possibly threatening this bivalve species.

Assuntos

RESUMO

The explosion of the Deepwater Horizon (DWH) oil platform resulted in large amounts of crude oil and dispersant Corexit 9500A® released into the Gulf of Mexico and coincided with the spawning season of the oyster, Crassostrea virginica. The effects of exposing gametes and embryos of C. virginica to dispersant alone (Corexit), mechanically (HEWAF) and chemically dispersed (CEWAF) DWH oil were evaluated. Fertilization success and the morphological development, growth, and survival of larvae were assessed. Gamete exposure reduced fertilization (HEWAF: EC201h=1650µg tPAH50L(-1); CEWAF: EC201h=19.4µg tPAH50L(-1); Corexit: EC201h=6.9mgL(-1)). CEWAF and Corexit showed a similar toxicity on early life stages at equivalent nominal concentrations. Oysters exposed from gametes to CEWAF and Corexit experienced more deleterious effects than oysters exposed from embryos. Results suggest the presence of oil and dispersant during oyster spawning season may interfere with larval development and subsequent recruitment.

Assuntos

RESUMO

Lightsticks are artifacts used as attractors in a type of commercial fishery, known as surface longline gear. Despite the excessive use, the contamination risks of these devices have not yet been properly investigated. This research aimed to fill up this gap by determining the chemical composition and the toxicity of lightsticks recently activated, compared to those one year after activation and to the ones collected on the beaches. The analyzes were carried out by Gas Chromatography coupled with Mass Spectrometry (GC-MS). Additionally, the variations in composition and the toxicity of their sea Water Soluble Fractions (WSF) were evaluated based on the WSF-effects of Crassostrea rhizophorae embryonic development. The GC-MS analysis made possible the identification of nineteen substances in the water soluble fraction of the lightsticks, such as dibutyl phthalate (DBP) and dimethyl phthalate (DMP). The value of the WSF-effective concentration (EC50) was in an average of 0.35%. After one year of the lightsticks activation, the toxicity was even higher (0.65%). Furthermore, other substances, also present in the lightsticks-WSF caused persistent toxicity even more dangerous to the environment than DBP and DMP. This essay discusses their toxicity effects and possible environment damages.

Assuntos

RESUMO

The aim of this study was to verify the yield of hatchery produced seeds of the mangrove oyster Crassostrea gasar cultivated, from May to July (2008), in a floating boxes system at two locations (4832"W - 2729"S, Sambaqui - Florianópolis and 4850"W - 2628"S, Iperoba - São Francisco do Sul). Management with pressured freshwater was performed weekly and four standardized sifting was done twice a month. At each sifting, the volume of seeds was calculated, as well as quantified by size. The results have shown the yield of 95.3% in Sambaqui and 58.7% in Iperoba, after nine weeks of cultivation and four siftings. Management techniques of seed used for Crassostrea gigas have proven to be efficient for the native species C. gasar. Both locations can be considered appropriate for the step of growing seeds.

O objetivo deste estudo foi verificar o rendimento de sementes de ostras do mangue Crassostrea gasar provenientes de laboratório, cultivadas de maio a julho de 2008, no sistema de caixas flutuantes, em duas localidades no estado de Santa Catarina (4832"O - 2729"S, Sambaqui - Florianópolis e 4850"O 2628"S, Iperoba - São Francisco do Sul). Semanalmente, foram realizados manejos com jato de água doce e, quinzenalmente, separação por tamanho, com quatro peneiras padronizadas (de malha 4 a 7 mm entre nós). A cada peneiramento, foram calculados os volumes e quantificadas as sementes por classe de tamanho. Após nove semanas de cultivo, os resultados mostraram rendimento de 95,3% no Sambaqui e de 58,7% no Iperoba. As técnicas de manejo de sementes utilizadas para Crassostrea gigas mostraram-se eficientes para a espécie nativa C. gasar. Os dois locais podem ser considerados apropriados para a etapa de cultivo de sementes.

Assuntos

RESUMO

The aim of this study was to verify the yield of hatchery produced seeds of the mangrove oyster Crassostrea gasar cultivated, from May to July (2008), in a floating boxes system at two locations (4832"W - 2729"S, Sambaqui - Florianópolis and 4850"W - 2628"S, Iperoba - São Francisco do Sul). Management with pressured freshwater was performed weekly and four standardized sifting was done twice a month. At each sifting, the volume of seeds was calculated, as well as quantified by size. The results have shown the yield of 95.3% in Sambaqui and 58.7% in Iperoba, after nine weeks of cultivation and four siftings. Management techniques of seed used for Crassostrea gigas have proven to be efficient for the native species C. gasar. Both locations can be considered appropriate for the step of growing seeds.(AU)

O objetivo deste estudo foi verificar o rendimento de sementes de ostras do mangue Crassostrea gasar provenientes de laboratório, cultivadas de maio a julho de 2008, no sistema de caixas flutuantes, em duas localidades no estado de Santa Catarina (4832"O - 2729"S, Sambaqui - Florianópolis e 4850"O 2628"S, Iperoba - São Francisco do Sul). Semanalmente, foram realizados manejos com jato de água doce e, quinzenalmente, separação por tamanho, com quatro peneiras padronizadas (de malha 4 a 7 mm entre nós). A cada peneiramento, foram calculados os volumes e quantificadas as sementes por classe de tamanho. Após nove semanas de cultivo, os resultados mostraram rendimento de 95,3% no Sambaqui e de 58,7% no Iperoba. As técnicas de manejo de sementes utilizadas para Crassostrea gigas mostraram-se eficientes para a espécie nativa C. gasar. Os dois locais podem ser considerados apropriados para a etapa de cultivo de sementes.(AU)

Assuntos

RESUMO

Camamu Bay, an Environmentally Protected Area, may be affected by the pressures of tourism and oil exploration in the adjacent continental platform. The current quality of the mangrove sediments was evaluated by porewater bioassays using embryos of Crassostrea rhizophorae and by an analysis of benthic macrofauna and its relationships with organic compounds, trace metals and bioavailability. Porewater toxicity varied from low to moderate in the majority of the samples, and polychaetes dominated the benthos. The Grande Island sampling station (Station 1) presented more sandy sediments, differentiated macrobenthic assemblages and the highest metal concentrations in relation to other stations and guideline values, and it was the only station that indicated a possible bioavailability of metals. The origin of the metals (mainly barium) is most likely associated with the barite ore deposits located in the Grande and Pequena islands. These results may be useful for future assessment of the impact of oil exploration in the coastal region.

Assuntos