Consulta: creatorFacets:"Tackx, M.L.M."
Registros recuperados: 6
Data/hora: 09/06/2024 04:39:27

Interpretation of particle spectra of electronic counters by microscopical methods
Provedor de dados: 27
Autores: Bakker, C.; Prins, T.C.; Tackx, M.L.M.
1. Using monocultures or single species dominated natural phytoplankton, cell counts and volume estimations obtained by visual and electronic methods show reasonable agreement.Calibration seems possible (Figs.1-2).2. Further examples given (Fig. 3-4) show that microscopical identification of the volume peaks in electronic counter spectra of natural seston is not quite simple. Phytoplankton peaks may not be detected in the Counter spectrum. Shifts of Counter peaks to the left side of the visual spectrum may be found when cylindrical, elongated or needle- like phytoplankton dominate the sample.3. Both visual and electronic methods include potentially large errors. Possibly particle volume is either overestimated by the microscope and / or underestimated by...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Detritus; Grazing; Measuring devices; Particle counters; Particle size; Phytoplankton; Zooplankton.
Ano: 1985
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3195

Calculations of results in grazing experiments using the counting method
Provedor de dados: 27
Autores: Tackx, M.L.M.; Van de Vrie, E.M.
Different formulae used in the literature for calculation of ingestion rates are reviewed. Their applicability is discussed in relation to two criteria: the occurrence of saturation of the feeding and/or growth of the food particles. It is shown by simulations that the differences in results obtained by calculating ingestion following a linear or an exponential model are restricted to a few percent. Calculation of ingestion rates by substantial over- or underestimation depending on the growth constant of the food particles and the grazing time.The formula I = Vk(C&lt;sub&gt;zt&lt;/sub&gt;C&lt;sub&gt;zo&lt;/sub&gt;e&lt;sup&gt;kt&lt;/sup&gt;)/N(I-e&lt;sup&gt;kt&lt;/sup&gt;) is proposed for the calculation of ingestion rates under saturated circumstances.It...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Food intake; Food intake; Grazing; Ingestion; Mathematical analysis; Measuring devices; Phytoplankton; Zooplankton.
Ano: 1985
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3212

Plankton size distributions and trophic relations before and after the construction of the storm-surge barrier in the Oosterschelde estuary
Provedor de dados: 27
Autores: Tackx, M.L.M.; Herman, P.M.J.; Van Rijswijk, P.; Vink, M.; Bakker, C.
Phytoplankton and zooplankton biomass distributions were calculated on a carbon basis for the inland part of the Oosterschelde, in the period before (1983), during (1984, 1986) and after (1987, 1988) the construction of the storm-surge barrier. In all years studied, both phytoplankton and zooplankton distributions are very irregular, and little consistent patterns emerge. The data were used to test the model of Sheldon et al. (1977). The observed standing stock ratios of zooplankton to phytoplankton agree with the model predictions in 1983, and are slightly higher during the period 1984-1987. In 1988, the model predictions are very different from the observed values, because of important changes in the zooplankton species abundance occurring in this year.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Particles; Particles; Particles; Plankton; Size distribution; Spectra; Zooplankton; Netherlands.
Ano: 1994
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2675

Image analysis as a tool for measuring particulate matter concentrations and gut content, body size, and clearance rates of estuarine copepods: validation and application
Provedor de dados: 27
Autores: Billiones, R.G.; Tackx, M.L.M.; Flachier, A.T.; Zhu, L.; Daro, M.H.
The performance of image analysis in measuring suspended particulate matter concentrations was compared with that of the Coulter counter in different samples including latex spheres, diatoms and natural estuarine waters. The two techniques gave comparable numerical concentrations. Image analysis results also correlated positively with dry weight measurements of estuarine suspended particulate matter samples. The conversion of particle areas measured by image analysis into volumes was addressed by trying to determine the average height of the particles. This was done by plotting volume concentrations from the Coulter counter against area concentrations from image analysis. The resulting linear relationships were found to be significant in homogeneous...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Image analysis; Image analysis; Image analysis.
Ano: 1999
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3992

Measuring selectivity of feeding by estuarine copepods using image analysis combined with microscopic and Coulter counting
Provedor de dados: 27
Autores: Tackx, M.L.M.; Zhu, L.; De Coster, W.; Billones, R.G.; Daro, M.H.
Although estuarine zooplankters are generally believed to be detritivorous, high clearance rates by the estuarine copepods &lt;i&gt;Eurytemora affinis&lt;/i&gt; and &lt;i&gt;Acartia tonsa&lt;/i&gt; on natural estuarine microplankton have been reported in the literature. In order to enable detection of possible selectivity for these microplankton organisms over detritus, a method that measures clearance rates on total particulate matter is proposed. Image analysis is used to measure copepod gut contents, and combined with Coulter counter measurements of total particulate matter concentration, allows one to calculate clearance rates on the latter. The first results indicate that, in the Westerschelde estuary (SW Netherlands), both &lt;i&gt;E....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Estuarine organisms; Feeding behaviour; Image processing; Selective feeding; Acartia tonsa; Copepoda [copepods]; Eurytemora affinis.
Ano: 1995
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2632

Size and phytoplankton selection by Oosterschelde zooplankton
Provedor de dados: 27
Autores: Tackx, M.L.M.; Bakker, C.; Francke, J.W.; Vink, M.
Grazing of adults of the copepods &lt;i&gt;Acartia&lt;/i&gt; spp., &lt;i&gt;Temora longicornis, Centropages hamatus&lt;/i&gt; and nauplii of &lt;i&gt;Balanus&lt;/i&gt; spp. on natural particulate matter from the Oosterschelde was studied using a Coulter counter. Two types of particulate matter distributions were found to occur in the Oosterschelde: 1. distributions with distinct peaks in the &gt;20 µm size range (A) and 2. more flattened distributions which were bell-shapened or contained multiple small peaks spread over the entire 4-100 µm size range (B). In A-type distributions, peak tracking was performed in all species studied, especially in &lt;i&gt;Acartia&lt;/i&gt; spp. and &lt;i&gt;T. longicornis&lt;/i&gt;. In B-type distributions, the animals...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Zooplankton ANE; Netherlands; Oosterschelde.
Ano: 1989
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3190