13 research outputs found
Pressure tolerance of tadpole larvae of the Atlantic ascidian Polyandrocarpa zorritensis: potential for deep-sea invasion
Resumo Dentre as teorias mais aceitas de como surgiu a fauna de oceano profundo está a de que organismos de águas rasas migraram para águas mais profundas e lá especiaram até originarem as comunidades de mar profundo atuais. No entanto, muitos organismos são impedidos de fazer longas migrações verticais por conta do aumento da pressão hidrostática. Larvas da ascídia Polyandrocarpa zorritensis foram submetidas a pressões de 1, 50, 100 e 200 atm. Taxas de sobrevivência, assentamento e metamorfose foram avaliadas após incubação de 24 horas em uma câmara de pressão. A maioria das larvas assentou (84%, 62%, 83% e 77%, respectivamente) e completou a metamorfose (93%, 59%, 85% e 60%) em todas as pressões. A mortalidade ficou abaixo de 15% para todas as pressões, com exceção do tratamento de 50 atm, em que a mortalidade ficou em 38%. Quase 100% das larvas sobreviventes completaram a metamorfose nos tratamentos de 1, 50 e 100 atm. No entanto, para o tratamento de 200 atm, 1/3 dos indivíduos ainda estavam no desenvolvimento larval e apresentaram um desenvolvimento atrasado. Esses resultados sugerem que larvas de ascídia podem suportar valores de pressão hidrostática que são encontrados no oceano profundo. Portanto, é provável que as atuais espécies de ascídias de oceano profundo podem tê-lo colonizado por meio de migrações verticais em algumas gerações.Abstract How deep-sea fauna evolved is a question still being investigated. One of the most accepted theories is that shallow water organisms migrated to deeper waters and gave origin to the deep-sea communities. However, many organisms are prevented from performing long vertical migrations by the increasing hydrostatic pressure. Tadpole larvae of the ascidian Polyandrocarpa zorritensis were submitted to pressure treatments of 1, 50, 100 and 200 atm. Survival, settlement and metamorphosis rates were verified after 24 hour incubation in a pressure chamber. The majority of larvae settled (84%, 62%, 83% and 77% respectively) and successfully underwent metamorphosis (93%, 59%, 85% and 60%) in all pressure treatments. Larval mortality was of less than 15% in all treatments, except for the 50 atm treatment, which presented 38% mortality. Nearly 100% of the surviving larvae underwent metamorphosis in the treatments of 1, 50 and 100 atm. However, 1/3 of the individuals were still in their larval stages in the 200 atm treatment and presented delayed development. These data suggest that ascidian larvae can withstand the hydrostatic pressure levels found in the deep-sea. It is therefore feasible that the current abyssal ascidian species may have colonized the deep-sea through vertical migration and in only a few generations
Pressure tolerance of tadpole larvae of the Atlantic ascidian Polyandrocarpa zorritensis: potential for deep-sea invasion
How deep-sea fauna evolved is a question still being investigated. One of the most accepted theories is that shallow water organisms migrated to deeper waters and gave origin to the deep-sea communities. However, many organisms are prevented from performing long vertical migrations by the increasing hydrostatic pressure. Tadpole larvae of the ascidian Polyandrocarpa zorritensis were submitted to pressure treatments of 1, 50, 100 and 200 atm. Survival, settlement and metamorphosis rates were verified after 24 hour incubation in a pressure chamber. The majority of larvae settled (84%, 62%, 83% and 77% respectively) and successfully underwent metamorphosis (93%, 59%, 85% and 60%) in all pressure treatments. Larval mortality was of less than 15% in all treatments, except for the 50 atm treatment, which presented 38% mortality. Nearly 100% of the surviving larvae underwent metamorphosis in the treatments of 1, 50 and 100 atm. However, 1/3 of the individuals were still in their larval stages in the 200 atm treatment and presented delayed development. These data suggest that ascidian larvae can withstand the hydrostatic pressure levels found in the deep-sea. It is therefore feasible that the current abyssal ascidian species may have colonized the deep-sea through vertical migration and in only a few generations. Dentre as teorias mais aceitas de como surgiu a fauna de oceano profundo está a de que organismos de águas rasas migraram para águas mais profundas e lá especiaram até originarem as comunidades de mar profundo atuais. No entanto, muitos organismos são impedidos de fazer longas migrações verticais por conta do aumento da pressão hidrostática. Larvas da ascídia Polyandrocarpa zorritensis foram submetidas a pressões de 1, 50, 100 e 200 atm. Taxas de sobrevivência, assentamento e metamorfose foram avaliadas após incubação de 24 horas em uma câmara de pressão. A maioria das larvas assentou (84%, 62%, 83% e 77%, respectivamente) e completou a metamorfose (93%, 59%, 85% e 60%) em todas as pressões. A mortalidade ficou abaixo de 15% para todas as pressões, com exceção do tratamento de 50 atm, em que a mortalidade ficou em 38%. Quase 100% das larvas sobreviventes completaram a metamorfose nos tratamentos de 1, 50 e 100 atm. No entanto, para o tratamento de 200 atm, 1/3 dos indivíduos ainda estavam no desenvolvimento larval e apresentaram um desenvolvimento atrasado. Esses resultados sugerem que larvas de ascídia podem suportar valores de pressão hidrostática que são encontrados no oceano profundo. Portanto, é provável que as atuais espécies de ascídias de oceano profundo podem tê-lo colonizado por meio de migrações verticais em algumas gerações. AbstrAct resumo Descritores: Oceano profundo, Pressão, Tolerância, Larva de ascídia, Polyandrocarpa zorritensis
Diet and feeding behavior of Kyphosus spp. (Kyphosidae) in a Brazilian subtropical reef
Morphological variations of post-marsupial stages of Sunampithoe pelagica Milne-Edwards (Crustacea, Amphipoda, Gammaridea, Ampithoidae) associated to Sargassum cymosum C. Agardh
The post-marsupial growth stages of the gammaridean ampithoid species Sunampithoe pelagica Milne-Edwards, 1830, six developmental stages for juveniles, three for females and at least seven for males, were described. The characterization was based on the increase of antennal article number, in the morphological modifications of gnathopods I and II, and on alteration of the number of setae.6573Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP
Diet and feeding behavior of Kyphosus spp. (Kyphosidae) in a brazilian subtropical reef
The present study analyzed and compared diet and feeding behavior (substrate use, position in water column, interactions with other fishes) of Kyphosus spp. (sea chubs) in a Brazilian subtropical reef. Juveniles (£ 160 mm) of Kyphosus incisor consumed both algae and invertebrates, which were mainly calanoid copepods. Juvenile and small adults of also observed foraging in the water column. We thus provide the first record of omnivory for Kyphosids in the southwest Atlantic Ocean
Diet and feeding behavior of Kyphosus spp. (Kyphosidae) in a brazilian subtropical reef
The present study analyzed and compared diet and feeding behavior (substrate use, position in water column, interactions with other fishes) of Kyphosus spp. (sea chubs) in a Brazilian subtropical reef. Juveniles (£ 160 mm) of Kyphosus incisor consumed both algae and invertebrates, which were mainly calanoid copepods. Juvenile and small adults of also observed foraging in the water column. We thus provide the first record of omnivory for Kyphosids in the southwest Atlantic Ocean
Assessment of Sargassum spp. macrofauna at Queimada Pequena Island, Ecological Station of Tupiniquins, southern coast of São Paulo State, Brazil
This work represents the first effort to assess the phytal macrofauna of Queimada Pequena island and was focused in mollusks, crustaceans and echinoderms associated to Sargassum spp. Sampling of the macrofauna was performed by random collections of 6 Sargassum fronds 6 m deep using SCUBA. The fronds were sealed underwater in individual 200 mm mesh bags and detached from the rocky shore. The samples were preserved in recipients in 10% formalin and carried to the laboratory to remove and identify the associated fauna. Forty one taxa were registered, with dominance of peracarid crustaceans. Mollusk composition is different from that of northern São Paulo coast. From the sixteen mollusk species recorded, only the gastropod genera Anachis and Odostomia and the bivalves Musculus and Modiolus were recorded in the Sargassum macrofauna at both coastal regions of São Paulo state, although the genus Fissurela had already been recorded at Santos region associated with the alga Amphiroa fragilissima. The occurrence of the exotic bivalve Isognomon bicolor was also confirmed. Our data suggest differences in the composition of molluskan fauna between southern and northern coasts of the state. Extensive investigations are necessary to confirm these results and to support management strategies in this conservation unit.Neste trabalho foi realizado o primeiro levantamento da macrofauna de fital da ilha da Queimada Pequena, focalizando o registro das espécies de moluscos, crustáceos e equinodermos associados a Sargassum spp. Para a amostragem da macrofauna associada, foram coletadas aleatoriamente 6 frondes de Sargassum localizadas a 6 m de profundidade, usando-se equipamento de mergulho autônomo. As frondes foram envolvidas em sacos de tecido com malha de 200 mm, mraspadas do substrato, colocadas em recipientes com uma solução de formaldeído 10% e levadas ao laboratório para remoção e identificação da fauna. Quarenta e um táxons foram identificados, havendo dominância de crustáceos peracáridos. Em relação aos Mollusca, a composição específica foi diferente em relação àquela observada na costa norte do estado de São Paulo. Das 16 espécies de moluscos encontradas, apenas os gastrópodes dos gêneros Anachis e Odostomia e os bivalves dos gêneros Musculus e Modiolus são representantes da fauna associada à Sargassum comuns às duas regiões do estado de São Paulo, embora representantes do gênero Fissurela já tenham sido relatados na região de Santos em associação à alga Amphiroa fragilissima. A ocorrência do bivalve exótico Isognomon bicolor também foi confirmada. Os dados obtidos sugerem que a fauna de moluscos pode realmente ser distinta na região norte e sul do estado. No entanto, são necessários estudos mais extensos para confirmar esses resultados e para subsidiar futuras estratégias de manejo dessa unidade de conservação.0