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| Registros recuperados: 18 | |
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| Weinberg, Steven. |
| An underwater ecological study, using a new methodological approach, was carried out on the hard substratum near Banyuls-sur-Mer (Pyrénées-Orientales, France). The data obtained were analyzed with a computer program, which showed the existing relationships between some physical parameters and the distribution of the animals studied: the Octocorallia. Light proved to be the most important ecological factor in the underwater stations studied. |
| Tipo: Article / Letter to the editor |
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| Ano: 1975 |
URL: http://www.repository.naturalis.nl/record/504518 |
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| Weinberg, Steven. |
| The autecology of eleven mediterranean octocoral species (3 Stolonifera, 4 Alcyonacea, 4 Gorgonacea) was studied near Banyuls-sur-Mer (southern France). Field observations were carried out by means of SCUBA-diving in forty underwater stations. The ecological amplitude of each species was determined for a number of abiotic factors, viz. water temperature, submarine irradiance, water movement, slope of substratum and sediment. In this way the ecological niche for the different species was defined. The niches of several species partly overlap: the survival “strategy” of these species was defined as “competitivity”. Other species display “specialization”, a strategy by which they avoid competitive situations. A third survival mechanism is “opportunism”,... |
| Tipo: Article / Letter to the editor |
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| Ano: 1979 |
URL: http://www.repository.naturalis.nl/record/504139 |
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| Weinberg, Steven. |
| Five gorgonian species are common on the rocky substratum of the Mediterranean circalittoral zone (Eunicella singularis, E. cavolinii, Lophogorgia ceratophyta, Paramuricea clavata, Corallium rubrum). Application of the priority rule of zoological nomenclature led to the renaming of two species. A complete description of all these animals is given, including colony form, morphology of the polyps, morphology and morphometry of the spicules. The latter were observed by means of light microscopy and scanning electron microscopy. Some new types of spicules were encountered. A short description of the ecology of each species is given. |
| Tipo: Article / Letter to the editor |
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| Ano: 1976 |
URL: http://www.repository.naturalis.nl/record/504986 |
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| Weinberg, Steven; Weinberg, Francisca. |
| The life cycle of the gorgonian Eunicella singularis has been studied with emphasis on larval behaviour, metamorphosis and annual growth. Planulae are found to have a mobile phase lasting from several hours to several days. Once settled, they metamorphose into a complete primary polyp in approximately four days. In the first year, budding will yield colonies of a height between 10 and 30 mm. Subsequently, average growth rates range from 14 to 33 mm year¯¹. Death may be due to several causes. Predators may partly denude the gorgonian branches, thus facilitating the settlement of epibionts, which in turn may invade the entire skeleton, slowly pushing back the living tissue of the gorgonian. Colonies may also be torn off their substratum by wave or current... |
| Tipo: Article / Letter to the editor |
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| Ano: 1979 |
URL: http://www.repository.naturalis.nl/record/504633 |
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| Weinberg, Steven. |
| The Goldfish intestine normally contains a large number of lymphocytes, many of them being present in the epithelial layer. After stimulation with antigen, the number of lymphoid cells does not increase, but the proportion of large pyroninophilic cells and plasma cells does. It seems therefore that transformation of B-lymphocytes into plasma cells occurs within the gut epithelium. The Goldfish intestine might be considered a primitive bursa equivalent. |
| Tipo: Article / Letter to the editor |
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| Ano: 1975 |
URL: http://www.repository.naturalis.nl/record/504357 |
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| Weinberg, Steven; Cortel-Breeman, Anneke. |
| The yearly cycle of surface solar irradiance at Banyuls-sur-Mer is derived from meteorological data. Monthly irradiance attenuation coefficients of the seawater were obtained from Secchi disc readings, which enabled the authors to classify the monthly optical water types according to Jerlov's classification. The average daily values of submarine irradiance are calculated for each month, and for different depths. Calculations have been carried out for the visible spectrum (350-710 nm) subdivided into 20 nm bands. Submarine irradiance is given in energetic (cal cm-² day-¹) as well as quantum (µE m-² ѕ-¹) units. Some considerations are given for underwater stations with different degrees of exposition to available light. |
| Tipo: Article / Letter to the editor |
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| Ano: 1978 |
URL: http://www.repository.naturalis.nl/record/504016 |
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| Weinberg, Steven. |
| Branches of gorgonians belonging to four different Mediterranean species (Eunicella singularis (Esper), Paramuricea clavata (Risso), Corallium rubrum (Linnaeus) and Lophogorgia ceratophyta (Linnaeus)) were transplanted to different habitats by means of three different methods, and survival and growth rates were observed over periods ranging from three months to over two years. It was concluded that transplantation of animals still fixed on their natural substratum is to be preferred over transplantations involving artificial devices. Transplanted adult branches of all four species tolerate conditions under which the species are not usually encountered. Tolerances or preferences of larval and juvenile phases must account for these discrepancies. Transplants... |
| Tipo: Article / Letter to the editor |
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| Ano: 1979 |
URL: http://www.repository.naturalis.nl/record/503915 |
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| Weinberg, Steven. |
| The behaviour of Mediterranean octocoral planulae was studied in light-dark situations and in a light gradient. Larvae of Eunicella singularis (Esper, 1794) reacted photopositively but it is uncertain which mechanism (klinotaxis or klinokinesis) determines this property. The blind larvae probably possess a dermal light sense, but it cannot be excluded that the yolk contains photosensitive carotenoids while the symbiotic zooxanthellae may also play a role. The photopositive behaviour of planulae of this species explains some aspects of the distributional ecology of adult colonies. It was also found that for the induction of settlement and metamorphosis the chemical properties of a given substratum seem to be far more important than its roughness. Larvae of... |
| Tipo: Article / Letter to the editor |
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| Ano: 1979 |
URL: http://www.repository.naturalis.nl/record/504260 |
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| Weinberg, Steven. |
| Seven coral reef survey methods were compared in an experimental plot of 100 m² on a Caribbean shelf reef off southwest Puerto Rico. This area was mapped in detail by means of underwater photography and in situ drawings, in order to provide an objective standard against which to test the results obtained by the different survey methods. Minimal survey area was determined, and minimal sampling time deduced for one of the most laborious methods. Two 45-minute periods (i.e. 1.6 X minimal time) were chosen arbitrarily as the standard time alotted to each method. Three survey criteria were chosen: number of species observed, relative coverage (in %) and population densities (in colonies m²). The results of the latter two methods were compared to real values (as... |
| Tipo: Article / Letter to the editor |
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| Ano: 1981 |
URL: http://www.repository.naturalis.nl/record/504554 |
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| Weinberg, Steven. |
| A new stoloniferan octocoral from the Mediterranean (Morocco) is described under the name Clavularia carpediem and critically compared with C. marioni Von Koch, 1891 and C. arctica (Sars, 1861). A thorough redescription of the latter species is given. The recent discovery that the common rock-dwelling colonies belonging to a species hitherto referred to as C. ochracea Von Koch, 1878 incubate their eggs on the outside of the polyps, a rather unusual fact among Octocorallia, leads to the synonymy of this species with C. crassa (Milne Edwards, 1848), so far considered a rare species living exclusively as an epibiont on the Mediterranean sea-grass Posidonia oceanica. |
| Tipo: Article / Letter to the editor |
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| Ano: 1986 |
URL: http://www.repository.naturalis.nl/record/504442 |
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| Weinberg, Steven. |
| Qualitative sampling of Octocorallia in 226 underwater stations at 23 localities between Marseille and Sardinia yielded information about their tolerances with respect to depth, slope, sediment and relative irradiance. The results are confronted with those previously obtained for the Banyuls area, and some conclusions are drawn regarding the existence of typical habitat-induced Octocorallian communities. |
| Tipo: Article / Letter to the editor |
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| Ano: 1980 |
URL: http://www.repository.naturalis.nl/record/504050 |
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| Weinberg, Steven. |
| Six stoloniferan species (Cornularia cornucopiae, Clavularia crassa, C. ochracea, C. marioni, “Anthelia” inermis and Rolandia rosea) from the Mediterranean circalittoral zone are described, nearly all of them occurring as epizoa on other organisms as well as on rocky substrata. Application of the rule of priority led to the change of one generic name, while several animals previously described as separate species were regrouped under their senior synonyms. A complete description of all these animals is given including colony form, morphology of the living polyps, morphology and morphometry of the sclerites. The latter were observed by means of light microscopy and scanning electron microscopy. A short description is given of the ecology of each species. |
| Tipo: Article / Letter to the editor |
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| Ano: 1978 |
URL: http://www.repository.naturalis.nl/record/505132 |
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| Weinberg, Steven. |
| Five alcyonarian species ( Alcyonium palmatum, A. acaule, Parerythropodium coralloides, Maasella edwardsi, Paralcyonium spinulosum) from the Mediterranean circalittoral zone are described, all but one ( Alcyonium palmatum) occurring on rocky bottoms. Application of the priority rule of zoological nomenclature led to the renaming of one species, while in another case a different generic name is applied. A complete description of the five species is given including colony form, morphology of the living polyps, morphology and morphometry of the spicules. The latter were observed by means of light microscopy and scanning electron microscopy. The ecology of each species is briefly described. |
| Tipo: Article / Letter to the editor |
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| Ano: 1977 |
URL: http://www.repository.naturalis.nl/record/505058 |
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| Weinberg, Steven. |
| Five differently coloured specimens of Parerythropodium are compared. A large series of spicules, originating from four distinct body regions, has been photographed and measured. These data are compared statistically. It is concluded that all five specimens belong to the same species, P. coralloides (Pallas, 1766). The ultrastructure of the spicules has been examined with the scanning electron microscope. |
| Tipo: Article / Letter to the editor |
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| Ano: 1975 |
URL: http://www.repository.naturalis.nl/record/504877 |
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| Registros recuperados: 18 | |
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