|
|
|
| Registros recuperados: 19 | |
|
|
| Vranken, G.; Thielemans, L.K.; Heip, C.H.R.; Vandycke, M.. |
| <i>Monhystera parelegantula</i> (De Coninck,1943) was collected from the sediment of the Sluice-dock, a euhaline-polyhaline lagoon near the harbour of Ostend (Belgium). The species was cultivated in large numbers on a bacto-agar medium with bacterial growth. Embryonic growth was studied at 30 °C and 30 promille S. Maximum embryonic length-growth occurs at the vermiform stage. Post-embryonic length-growth, studied at 25 °C and 30 promille S, is a linear function of time and may be expressed as l = 160.46 + 29.55(t-t<sub>o</sub>), where t<sub>o</sub> = time at the beginning of development; t and l = time (d) and length (µm). At 25 °C and 30 promille S, average embryonic development time and generation time are 4 and 9 d... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Life cycle Monhystrella parelegantula ANE; Belgium; Oostende Harbour; Sluice Dock. |
| Ano: 1981 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3410 |
| |
|
| |
|
|
| Vranken, G.; Vanderhaeghen, R.; Van Brussel, D.; Heip, C.H.R.; Hermans, D.. |
| The influence of the mercury compounds Hg<sub>2</sub>Cl<sub>2</sub>, HgCl<sub>2</sub>, and CH<sub>3</sub>HgCl as measured by egg mortality, preadult mortality, and development time, was studied on the marine nematode <i>Monhystera disjuncta</i>. A significant influence on egg, juvenile, and preadult mortality was observed for Hg<sub>2</sub>Cl<sub>2</sub> and HgCl<sub>2</sub>, while CH<sub>3</sub>HgCl did not cause egg mortality. It was concluded that the juvenile mortality is the most sensitive index for the chronic stress. No apparent changes in the development time occurred. The acute toxicity of the above mentioned mercury compounds, measured as... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Mercury; Toxicity; Monhystera disjuncta. |
| Ano: 1984 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3277 |
| |
|
|
| Vranken, G.; Van Brussel, D.; Vanderhaeghen, R.; Heip, C.H.R.. |
| The brackish-water nematodes <i>Monhystera disjuncta</i> and <i>Monhystera microphtalma</i> were chosen as test organisms for ecotoxicological studies. Both species are locally abundant, have short life cycles and can be maintained for several generations under laboratory conditions. They reproduce very well on a sloppy bacto-agar (0.5-0.8%) made up with water of the natural habitat, enriched with 1% Vlasblom medium (Vlasblom, pers. commun.) and 1% silicium (15g.l<sup>-1</sup>), reaching densities of approximately 1000 individuals.cm<sup>-2</sup>. Starting from such agnotobiotic cultures, a chemically defined artificial medium has been developed. This medium consists of 0.5% bacto-agar in artificial seawater,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Toxicity tests Monhystera disjuncta Monhystera microphtalma de Man; 1880. |
| Ano: 1984 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3276 |
| |
|
|
| Vranken, G.; Heip, C.H.R.. |
| Toxicity of copper, lead and mercury to the nematode <i>Diplolaimella</i> spec 1 is studied. Mortality responses obtained demonstrate high resistance to heavy metals. Population growth parameters as the intrinsic rate of natural increase and net-reproductivity are significantly depressed at copper-concentrations which cause no juvenile mortality. The lowest concentrations tested caused significant inhibition of development rate in both sexes. For this particular nematode species suppression of fecundity and developmental inhibition are more reliable criteria, determining non-exceedable limits with regard to environmental safety. Our tests show that nematode productivity may be significantly depressed at copper levels found in some areas of the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Copper; Lead; Mercury; Toxicity; Nematoda [Nematodes]. |
| Ano: 1986 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3250 |
| |
|
| |
|
| |
|
| |
|
|
| Herman, P.M.J.; Vranken, G.; Heip, C.H.R.. |
| The direct estimation of energy flow through marine meiobenthic populations poses several difficulties, mainly relating to sampling problems. The usefulness of some indirect estimation methods is discussed. Direct production estimates and respiration measurements for three brackish water crustacean populations are given, indicating a relative constant proportion between population production and respiration.The production: assimilation ratio for these populations fluctuates between 0.3 and 0.4. This is contrasted to literature data revealing much higher production: assimilation ratios as determined in the laboratory for nematode populations. Using data on laboratory cultures of the nematode <i>Monhystera disjuncta</i> some factors that can... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Energy flow; Meiobenthos. |
| Ano: 1984 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3265 |
| |
|
|
| Heip, C.H.R.; Vincx, M.; Vranken, G.. |
| Nematodes are probably the most abundant metazoans in the biosphere and of very great importance to man. As parasites of man they are responsible for disease in hundreds of millions of people and an estimated eight billion nematodes are enjoying food, warmth and shelter in human intestines today; <i>Ascaris lumbricoides</i> is, after the viruses responsible for diarrhoeal disease, the second most infectious organism in the world, about a quarter of the world's population being infected (Ash, Crompton & Keymer, 1984). Plant-parasitic nematodes cause considerable damage to crops and many species are vectors of soil-borne viruses. Today, plant nematology is one of the most vital fields in agricultural research and is studied in many university... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ecology; Literature reviews; Nematoda [Nematodes]. |
| Ano: 1985 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3205 |
| |
|
| |
|
|
| Vranken, G.; Heip, C.H.R.. |
| The life-cycle of <i>Rhabditis marina</i> Bastian 1865 was studied at 25°C and 20 promille salinity. The following demographic parameters were computed from life-table data: the intrinsic rate of natural increase (r<sub>m</sub>) = 0.914 day; net reproductivity (R<sub>0</sub>) = 400; minimum generation time (T<sub>min</sub>) = 4.5 days; cohort generation time (T<sub>c</sub>) = 7.2 days; mean generation time (T) = 6.6 days; and the age of an adult female when a median egg is deposited (T) = 6.1 days. Several approximate equations used to estimate r<sub>m</sub> were compared with these life-table calculations. Some give erroneous estimations and should be used with extreme caution. For... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Population characteristics; Nematoda [Nematodes]; Rhabditis marina. |
| Ano: 1983 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3260 |
| |
|
|
| Herman, P.M.J.; Heip, C.H.R.; Vranken, G.. |
| The ostracod <i>Cyprideis torosa</i> Jones,1985 is a dominant species in the meiofauna of brackish water habitats. Its production in the field over a five-year period has been calculated using two production models. The first model uses the age-distribution of shells preserved in the sediment to assess the stage-specific mortality rates and the stage durations. The second model is the size-frequency model, modified for use with development stages instead of size-classes. Productions calculated with both methods agree very well. Their values are 9.7 and 9.2 g dwt.m<sup>-2</sup>y<sup>-1</sup> respectively. The yearly P/B-ratio is 2.7 or 2.6y<sup>-1</sup>, production efficiency P/A is 0.38 or 0.37. The... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Secondary production; Cyprideis torosa. |
| Ano: 1983 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3396 |
| |
|
| |
|
|
| Heip, C.H.R.; Vincx, M.; Smol, N.; Vranken, G.. |
| Nematodes are the most abundant metazoans in marine (littoral, estuarine, coastal and oceanic) sediments, extending from the high-water mark into the deepest oceanic trenches (Nicholas, 1975). All marine free-living nematodes are considered to be members of the meiobenthos; small organisms, mainly metazoans, which are separated from the larger macrobenthos either on a methodological basis (i.e. as all animals passing a 1 mm or a 0.5 mm sieve) or a taxonomic basis (i.e. particular animal groups such as Nematoda, Harpacticoida, Gastrotricha, Kinorhyncha, Tardigrada, Foraminifera etc. which consist exclusively or mainly of small species living in sediments). In most circumstances, nematodes are numerically the dominant group of the meiofauna. In fact, they... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ecology; Systematics; Taxonomy; Nematoda [Nematodes]. |
| Ano: 1982 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3417 |
| |
|
| |
|
| |
| Registros recuperados: 19 | |
|
|
|
