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| Registros recuperados: 2,423 | |
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| Vanhaecke, P.; Lavens, P.; Sorgeloos, P.. |
| Variations in dry weight, caloric content and ash content during cyst hatching and early larval development have been studied for various geographical strains of <i>Artemia</i> . In general, decapsulated cysts contain 30 to 40% more energy than freshly hatched nauplii; for Chaplin Lake and Buenos Aires <i>Artemia</i> this difference amounts to 57%. Ash contents increase as decapsulated cysts hatch into instar I and molt into instar II-III nauplii. Over a 24h larval developmental period individual dry weights and energy content of the nauplii decrease with 16-34% and 22-37% respectively.A small but significant correlation exists between the survival rate of starved nauplii and either the energy content of instar I and instar II-III... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cysts; Energy budget; Larval stages; Artemia. |
| Ano: 1983 |
URL: http://www.vliz.be/imisdocs/publications/261926.pdf |
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| Claus, C.; Maeckelberghe, H.; De Pauw, N.. |
| From October to April the growth of spat of <i>Ostrea edulis, Crassostrea gigas</i> and <i>Venerupis semidecussata</i> in an onshore nursery was recorded as a function of water temperature and food level. The results of this study indicate that even very eutrophic water, such as that of the Sluice Dock at Ostend, Belgium, does not provide enough microalgae to sustain growth of bivalve spat during winter, irrespective of whether the water is heated or not. It is necessary to supply additional food (cultured live algae). Food shortage for three months at higher temperature induced a stress situation resulting in high mortality rates, even after transferring all the spat into an optimal combination of temperature and food availability. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aquaculture techniques; Rearing; Bivalvia; Molluscs; Belgium. |
| Ano: 1983 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3369 |
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| Roekens, E.J.; Van Grieken, R.E.. |
| The rate of iron(II) oxidation in the North Sea water of pH 5.5-10 in the range 10-25°C has been studied. The oxygenation rate depends linearly on the iron(II) and dissolved oxygen concentrations. The second-order dependence on (OH<sup>-</sup>), found by several investigators for synthetic solutions, was confirmed in seawater, but only for pOH>6.9. For pOH<5.9 the rate appeared to be independent of the pOH. In the intermediate range, pOH<5.9-6.9, corresponding to the natural pH of seawater, a first-order dependence on the pOH is obeyed. The important discrepancy in the literature between the second-order rate constant for NaCHO<sub>3</sub> solutions and for seawater can be attributed predominantly to the incorrect... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Iron; Kinetics; Oxidation. |
| Ano: 1983 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3293 |
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| Bastin, A.; Malherbe, B.; Caillot, A.. |
| An extensive program of tracer experiments was carried out for calculating sediment transport in the vicinity of the Port of Zeebrugge where extension operations are in progress. Offshore radioactive bottom tracers were used for studying the sand transport along the beaches where erosion problems exist. On the beach itself fluorescent tracers were used. For the evaluation of the silting-up rate of the access channels to the harbour a series of radioactive bottom and suspension tracers were tracked <i>in situ</i>. For determining the efficiency of future dumping grounds a combination of bottom tracers and suspension tracers was used. In total, 18 experiments with radioactive tracers were carried out and 9 with fluorescent ones. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: ANE; Belgium; Belgian Coast. |
| Ano: 1983 |
URL: http://www.vliz.be/imisdocs/publications/128948.pdf |
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| Bergmans, M.. |
| Caswell and Hastings (1980) introduced an explicit model for the relative merits, in terms of growth rate <i>lambda</i>, of developmental shifts vs. fecundity increases. Some aspects of their model are clarified by concentrating on the (fitness >1) half-plane rather than on the (accelerated reproduction) half-plane. There is no strict equivalence between Caswell and Hastings' key parameter <i>lambda/P</i> and the dynamic behaviour of the population which is governed by <i>lambda</i>. Thus in some stationary/declining populations time shifts of reproduction (forward or backward, according to the value of <i>lambda/P</i>) are just as effective in promoting a high <i>lambda</i> as they are in... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Population parameters. |
| Ano: 1983 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3364 |
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| Vandamme, K.; Maertens, D.. |
| Polychlorinated biphenyls (PCBs) and some organochlorine pesticides we re measured in some marine organisms of different trophic levels, sampled in the Belgian coastal waters. Because of their persistence and their lipophilic character they accumulate in lipoidal tissues, causing higher organochlorine residue levels in animals with a high adiposity. To compare the residue levels of different organisms lipid based data must be used.The concept of biological magnification controlled by mass transfers of residues through food chains is questioned because predatory fish like cod contained similar or even lower residue levels than organisms of a lower trophic levellike the peacock worm. This supports the concept that the organochlorine levels are controlled by... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Organometallic compounds; Trophic levels. |
| Ano: 1983 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3259 |
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| Henriet, J.-P.; D'Olier, B.; Auffret, J.P.; Andersen, H.L.. |
| A joint seismic exploration programme, carried out in recent years by Belgian, British, French and Danish university laboratories in the southern North Sea and Schelde estuary, has revealed various styles of clay tectonics in Eocene and Oligocene deposits. In this paper particular attention is drawn on the remarkable deformation features observed in the Ieper or London clay, which forms the subsoil of the major part of the Thames estuary and the Belgian shelf sector. Those clay structures have eluded many previous investigations, mainly due to a lack of interfaces with large reflection coefficients. When however a seismic source is adequately tuned, the sum of reflection responses from the many subtle interfaces within the clay sequence may construct an... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Geological hazards Seismic exploration Tectonics ANE; North Sea; Southern Bight. |
| Ano: 1983 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3418 |
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| Maenhaut, W.; Raemdonck, H.; Selen, A.; Van Grieken, R.; Winchester, J.W.. |
| By using a polyester sailboat as sampling platform, a series of duplicate aerosol samples was collected by cascade impactors on a trip from Panama to Tahiti in 1979. Elemental analysis mainly by particle-produced X-ray emission (PIXE) indicated, in the samples collected between Panama and the Galapagos Islands, the presence of a substantial crustal component (0.4 µg/m³), fine Cu (0.4 ng/m³ and Zn (0.6 ng/m³), and excess fine S and K (100 and 2.4 ng/m³, respectively in addition to the major sea salt elements. The crustal component and fine Cu and Zn are suggested to result from natural continental sources (i.e., eolian dust transport from the American continents and perhaps geothermal emissions). Samples collected west of the Galapagos Islands in the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aerosols IS; Equatorial Pacific. |
| Ano: 1983 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3398 |
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| Vanhaecke, P.; Sorgeloos, P.. |
| A comparative hatching study has been carried out with reference <i>Artemia</i> cysts as well as cysts from Argentina, Australia, Brazil, Canada, France, Italy, the People' s Republic of China, the Philippines and the USA. Hatching rate, percentage and efficiency vary considerably from one cyst source to another. These hatching criteria are, however, not strainspecific since significant variation is found among cyst batches from the same geographical origin. The limitations of the "hatching efficiency" concept are discussed and a new criterion "hatching output", i.e. the biomass of nauplii expressed in mg dry weight produced per gram cyst product, is proposed for evaluation of the hatching quality of <i>Artemia</i> cyst brands. The... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Efficiency; Hatching; Artemia. |
| Ano: 1983 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3399 |
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| De Pauw, N.; Van Vaerenbergh, E.. |
| Algae can play a positive role in wastewater treatment by recycling of nutrients, by taking up carbon, nitrogen and phosphorus, by reducing the nutrient load through stripping and precipitation, by producing oxygen for bacterial decomposition of organic matter, by eliminating pathogenic bacteria through bactericide action, and last but not least by solving odor problems. If sufficient insolation, and space are available, intensive algal wastewater treatment-systems proved to be valuable and promising alternatives to conventional treatment systems based on activated sludge or trickling filters. The various technologies developed for algal wastewater treatment are commented in this review. They include simple stabilization-oxidation ponds, as well as more... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Waste water; Wastewater treatment. |
| Ano: 1983 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3350 |
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| Registros recuperados: 2,423 | |
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