Study of the feeding ecology of brackish-water nematodes
Vanaverbeke, J. (1993). Study of the feeding ecology of brackish-water nematodes. Belg. J. Zool. 123(Suppl. 1): 74-75
In: Belgian Journal of Zoology. Koninklijke Belgische Vereniging voor Dierkunde = Société royale zoologique de Belgique: Gent. ISSN 0777-6276; e-ISSN 2295-0451, more
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| Keywords |
Ecology
Feeding
Water > Brackish water
Nematoda [WoRMS]
ANE, Netherlands, Westerschelde [Marine Regions]
Brackish water |
| Abstract |
In the first pan of this work, vertical profiles of nematodes in a brackish-water mudflat were correlated with the environmental variables. Three stations in the Westerschelde were sampled. In the second part of this study, tracer experiments on agar were carried out to measure grazing of nematodes on diatoms and bacteria. The highest number of nematodes were found between 0.5 and 1 cm depth. Individual biomass was maximal between 1 and 1.5 cm in one station, in another one between 3 and 4 cm depth. Density of nematodes we re positively correlated with the concentration of chlorophyl a (except one station) and fucoxanthine and with the number of bacteria in the sediment. In two stations, a significant correlation with the median grain size was found. In each station densities were significantly correlated with the redox potential. No correlations were found between the individual biomass and any other variable. The vertical profiles of the nematodes are most influenced by the food supply: bacteria and diatoms. The most important chemical variable seems to be the redox potential. In the experimental part of the thesis was studied if grazing of nematodes on bacteria and diatoms in agar plates could be measured. Therefore, food was labeled and radioactivity in grazing nematodes was measured. Control-experiments were carried out as described by Montagna (1). When diatoms were used as food, the up take of radioactivity by nematodes was as described by Montagna (2). In experiments were bacteria were used as food, the model of Montagna (2) could not be found. The reason is that working with bacteria on agar plates is very difficult. Abiotic uptake of label by nematodes was measured in formalin-poisoned experiments. Abiotic uptake was very low. Uptake of label due to non-grazing activity was measured in dark-controls and non-grazing experiments. Non-grazing experiments seem to be the best experiments to control for non-grazing uptake.(I) P.A. MONTAGNA (1983). Mar. Ecol. Prog. Ser. 12:43-46.(2) P.A. MONTAGNA (1984).,Mar. Ecol. Prog. Ser.18:119-130. |
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