877 research outputs found

    Metridium senile: dispersion and small scale colonization by the combined strategy of locomotion and asexual reproduction (laceration)

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    The process of biotope occupation by the anenome Metridium s en~l ein the absence of pelagic larvae has been investigated by an in situ monitoring experiment lasting from July 1981 to April 1982. This process is composed of several behavioral phases: dispersion of the anemones on the new substrate by h ~ g hlo comotory activity, colonization of the 'chosen' habltat by intensive asexual reproduction and finally, a stationary phase. One characteristic of the particular ecological situation in the Flensburg fjord (Western Baltic) seems to be the absence in M senile of sexual reproduction and larvae resulting in a mono- or oligoclonality of the Fjord population. This study shows that even if pelagic dispersal is missing, local dispersion and proliferation can be assured by locomotion and laceration

    The fluffy sea anemone Metridium senile in periodically oxygen depleted surroundings

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    In SCUBA-diving monitored field experiments (Flensburg Fjord, 15 m, 1981) and parallel aquarium tests,the behavior of Metridium senile under anoxic conditions and its oxygen-deficiency resistance were studied. When oxygen is lacking the fluffy sea anemone diminishes body surface, and then, successively, shuts off most energy consuming activities. By means of this strategy, 50% of the tested individuals survived 3 weeks of total anoxi

    The Alkaloid Ageladine A, Originally Isolated from Marine Sponges, Used for pH-Sensitive Imaging of Transparent Marine Animals

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    The brominated pyrrole-imidazole Ageladine A was used for live imaging of the jellyfish (jellies) Nausithoe werneri, the sea anemone Metridium senile and the flatworm Macrostomum lignano. The fluorescence properties of Ageladine A allow for estimation of pH values in tissue and organs in living animals. The results showed that Nausithoe werneri had the most acidic areas in the tentacles and close to the mouth (pH 4–6.5), Metridium senile harbours aggregates of high acidity in the tentacles (pH 5) and in Macrostomum lignano, the rhabdoids, the gonads and areas close to the mouth were the most acidic with values down to pH 5

    Cnidoma de los tentáculos de la anémona de mar Metridium senile (Linnaeus, 1761) (Cnidaria: Anthozoa)

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    Tentacle cnidae of Metridium senile (Linnaeus, 1761) were examined by light microscopy. In addition to spirocysts, feeding-tentacles had 3 nematocyst categories grouped into medium and small size-classes, including 5 types. Spirocysts dominated, especially distally, followed by medium b-mastigophores. The density of cnidae decreased towards the tentacle base. Early cnidoblasts were numerous on the tentacle tip. Late cnidoblasts appeared in a moderate number on the mid-tentacle. Catch-tentacles, found in two Metridium specimens, had a maturity gradient of isorhizas and gland cells along their length. Their tip had two distinct types of mature isorhizas in great numbers and large gland cells, but lacked spirocysts. Mature isorhizas and gland cells decreased in number towards the tentacle base. On the mid-tentacle differentiating ages of isorhizas were numerous. Ordinary feeding-tentacle cnidae, abundant at the tentacle base, decreased in number distally along the tentacle.El cnidoma de los tentáculos de Metridium senile (Linnaeus, 1761) se examinó mediante microscopio óptico. Además de espirocistos, los tentáculos tenían 3 categorías de nematocistos agrupados en clases de talla medianas y pequeñas, incluyendo 5 tipos. Los espirocistos fueron dominantes, en particular distalmente, seguidos por b-mastigióforos medios. La densidad de cnidoma decreció hacia la base del tentáculo. En la punta del tentáculo fueron abundantes los cnidoblastos jóvenes. Los cnidoblastos avanzados aparecieron en número moderado a mitad del tentáculo. Los tentáculos hallados en dos especímenes de Metridium presentaron un gradiente de madurez de isorhizas y células glandulares a lo largo de su longitud. La punta tenía dos tipos distintos de isorhizas maduras en gran número y grandes células glandulares, pero les faltaban espirocistos. Las isorhizas maduras y las células glandulares disminuyeron en número hacia la base del tentáculo. A mitad del tentáculo, se observaron numerosas isorhizas de diferentes edades. Los cnidocistos de los tentáculos, abundantes en la base del tentáculo, disminuyeron en número distalmente a lo largo del tentáculo

    Nematocistos acontia y mesentéricos de la anémona de mar Metridium senile (Linnaeus, 1761) (Cnidaria: Anthozoa)

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    Acontia and mesentery nematocysts of Metridium senile (Linnaeus, 1761) are described from interference- contrast light micrographs (LMs) and scanning electron micrographs (SEMs). The acontia have 2 nematocyst categories grouped into small, medium and large size-classes, including 5 types: of these, large b-mastigophores and large p-amas- tigophores are the largest and most abundant. Mesenterial tissues, characterised by small p-mastigophores and medium p-amastigophores, have 3 nematocyst categories grouped as small and medium, including 6 types. Attention is given to nematocyst maturation, especially to the differentiation of the shaft into proximal and main regions as helical folding of the shaft wall proceeds. Groups of differentiating nematoblasts occur along acontia, and near the junction between acontia and mesenterial filaments. Nematoblasts are sparsely found throughout mesenterial tissues.Los acontios y los nematocistos de los mesenterios de Metridium senile (Linnaeus, 1761) se describen a partir de microfotografías de contraste-interferencia (LMs) y de microscopio electrónico de barrido (MEB). Los acontios tienen dos categorías de nematocistos agrupados en clases de talla, pequeños, medianos y grandes, incluyendo 5 tipos: de ellos, los mas grandes y abundantes son los b-mastigioforos grandes y los p-amastigióforos grandes. Los tejidos mesentéricos, caracterizados por pequeños p-mastigióporos y medianos p-amastigióforos, tienen 3 categorías de nematocistos agrupadas como pequeñas y medias, incluyendo 6 tipos. Se presta atención a la maduración de los nematocistos, especialmente a la diferenciación de los dardos en las regiones proximales y principales como plegamientos helicoidales de las paredes del dardo. A lo largo de acontia, y cerca de la unión entre los filamentos de acontia y filamentos mesentéricos aparecen grupos de nematoblastos en diferenciación. Los nematoblastos están escasamente representados en todos los tejidos mesentéricos

    Formación de los dardos en los nematocistos de la anémona de mar Metridium senile (Linnaeus, 1761) (Cnidaria: Anthozoa)

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    In examining large acontia b-mastigophore and p-amastigophore nematocysts of the sea anemone Metridium senile (Linnaeus, 1761) darts were observed by interference-contrast light microscopy (LM) and scanning electron microscopy (SEM). The darts consist of closely packed spines detached from the shafts, still in three helical rows. Their spines form a hollow cylinder with a sharp tip and indented base, its width similar to that of an undischarged shaft but varying in length. b-mastigophore darts were more common than those of p-mastigophores and many were longer.El examen mediante microscopía de contraste de fases (LM) y microscopio electrónico de barrido (MEB) de los grandes nematocistos acontios b-mastigóforos y p- amastigóforos de la anémona de mar Metridium senile (Linnaeus, 1761) permitió la observación de dardos. Los dardos consisten en espinas fuertemente empaquetadas desli- gadas de la punta del dardo, todavía en tres hileras helicoidales. Sus espinas forman un cilindro hueco con una punta afilada y una base no dentada, su anchura es similar a la de la punta de un dardo no descargado, pero varían en longitud. Los dardos b-mastigióforos fueron más frecuentes que los de p-mastigióforos y muchos de ellos fueron más largos

    The recolonization potential of Metridium senile in an area previously depopulated by oxygen deficiency

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    Every summer the deepest parts of the inner Flensburg fjord are subject to O2-deficiency lasting from a few weeks to several months. In spring, however, populations of Metridium senile can be found in these areas, in spite of the fact that frequently the local anoxic period of the previous summer has been 2–3 times longer than their anoxia LD50-value (3 wks). Responsible for this phenomenon is an intensive recolonization by adult Metridium during autumn and winter. This process has been investigated in an 8 months monitoring from May to December 1981. Results on the recolonization mechanism, the population structure of immigrating anemones and recolonization rate as a function of available hard substratum are presented

    An Examination Of Marine Fouling Organisms\u27 Presence On Varying Substrates In A New England Marina

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    Marine fouling communities are comprised of various marine organisms that begin life as planktonic larvae before attaching to submerged surfaces. The purpose of this study was to develop an understanding of the substrate preferences of marine organisms that commonly foul New England marinas. Two sets of four 14x14cm fouling plates were constructed out of one of four materials: polyvinyl chloride (PVC), fiberglass, concrete or slate. These plates were suspended off a floating dock at 1 and 2 meters below the surface of the water. The 16 plates were placed at the Boston Harbor Shipyard and Marina in East Boston, MA, on 17 July 2016 and photographed every two weeks until 4 December 2016 for a total of 20 weeks. Individual organisms were counted and the percent cover calculated for colonial species to examine what settled and general abundance. It was found that the most common fouling organisms were Ciona intestinalis, Molgula sp., and Botrylloides violaceus. Ascidiella aspersa and Botryllus schlosseri were also present. The two most common solitary species present on all plate materials were C. intestinalis and Molgula sp. with B. violaceus being the most common colonial species. C. intestinalis showed a preference for the concrete plates over the other available surfaces. B. violaceus was most common on the slate plates. All colonial ascidians were observed growing on other organisms showing their involvement in secondary settlement. Understanding the substrate preference of these species develops a baseline for further research and the potential to control the spread of invasive species naturally

    Feeding Behavior of Spurilla sp. (Mollusca: Opisthobranchia) with a Description of the Kleptocnidae Sequestered from Its Sea Anemone Prey

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    Feeding behavior of Spurilla sp. (Mollusca: Opisthobranchia) with a description of the kleptocnidae sequestered from its sea anemone prey. Zoological Studies 51(7): 905-912. Cnidocysts are sequestered from cnidarian prey by aeolid nudibranchs and stored in the tips of their appendages (cerata). The kleptocnidae of 11 specimens of Spurilla sp. are described in detail. The types and relative abundances of prey cnidocysts in nudibranch cerata were highly variable, suggesting exclusive anemone consumption. Spirocysts and several types of microbasic p-mastigophores, microbasic b-mastigophores, and basitrichs were found in external and internal tissues of sea anemone prey. This is the 1st report of predation of aeolid Spurilla sp. on the sea anemones Antholoba achates, Metridium senile lobatum, and Parabunodactis imperfecta from the rocky intertidal of Patagonia (Chubut Province, Argentina) and on Anthothoe chilensis and Tricnidactis errans at Mar del Plata (Buenos Aires Province, Argentina). Photographs and digital videos of aeolidacean feeding behavior were recorded in situ and in aquaria. The purpose of this study was to provide valuable information on the diet of Spurilla sp. from Argentina using field observations and descriptions of the kleptocnidae.Fil: Garese, Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: García Matucheski, Stella. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. San Martín; ArgentinaFil: Muniain, Claudia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Acuña, Fabian Horacio. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
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