The gross growth efficiency GGE of Strombidium sp. The carbon contents per cell for Strombidium sp. Protistan growth rate can be modeled as linear functions of temperature Atkinson et al. However, Kimmance et al. The difference in ingestion rates between oligotrich ciliates might be related to the size of grazers and the temperature used in the studies Yang et al. Hence, the grazing rates were not normalized in the present study.
Table 1. Parameters of growth rates for oligotrich ciliates in previous studies laboratory culture. Table 2. Parameters of ingestion rates for oligotrich ciliates in previous studies laboratory culture. The numerical response of Strombidium sp. Figure 1. Growth rate of Strombidium sp. The half-saturation constants K G for two culture conditions were similar, indicating the same requirement of prey concentration to achieve half of the maximum growth rate.
The threshold value x 0 of Strombidium sp. Figure 2 shows the functional response of Strombidium sp. For Strombidium sp. In contrast, the ingestion rate of Strombidium sp. Figure 2. Ingestion rate of Strombidium sp.
As for Strombidium sp. The maximum ingestion rate of Strombidium sp. The GGE at low prey concentration with negative growth and ingestion rates is shown as 0. Figure 3. Gross growth efficiency GGE of Strombidium sp. Ciliates can generally undergo 1—2 binary fissions per day Pierce and Turner, ; Perez et al. Both species of ciliate appear to have similar numerical responses at the same prey T-ISO concentrations.
The growth rate parameters for Strombidium sp. However, as the concentration of bacteria increased, the maximum growth rate of Strombidium sp. The ingestion rate parameters for oligotrich ciliates as recorded by previous studies are shown in Table 2 , with a maximum ingestion rate I max between 7. I max and K I of Strombidium sp.
The gross growth efficiency GGE of Strobilidium sp. Since these two ciliates have similar growth curves with the same prey T-ISO as mentioned above Table 1 , the high GGE at low prey concentrations makes it reasonable to speculate that Strobilidium sp. I max was 9. The half-saturation constant K I of Strombidium sp. Since Strombidium sp. In Figure 4 , the data points, where other two points representing negative ingestion rate were avoided in advance, showing the proportion of ingested carbon derived from bacteria versus the proportion of the carbon content in the environment i.
This shows that the ciliate Strombidium sp. Figure 4. Percentage of total ingested prey carbon content of bacteria when grazing on the haptophyte Isochrysis galbana in the presence of bacteria. The diagonal line means Briefly stated, Strombidium sp.
Gross growth efficiencies of the choreotrich ciliate Strobilidium sp. It is reasonable to assume that these authors did not control for the presence of bacteria in the algal culture medium Figure 5.
Figure 5. Lee and Fuhrman reported the coefficient of carbon content conversion of marine bacteria as approximately 20 fg C cell —1 and Kroer found that the carbon content of estuarine bacteria is fg C cell —1. Bacteria with a carbon content of fg C cell —1 were used in the present study. Figure 6 , in which a conversion coefficient of 20 fg C cell —1 for the bacteria was used, in accord with general practice in marine microbial ecology Lee and Fuhrman, , shows the same result as in Figure 4 where bacterial carbon content fg C cell —1.
In the present study, large bacteria were collected from coastal water, not small bacteria like those in the open ocean, and cultivated in a non-nutrient-limited environment. This makes as estimate of fg C cell —1 for bacterial cell carbon content is more appropriate than one of 20 fg C cell —1.
Figure 6. Percentage composition of total ingested prey carbon content for Strombidium sp. Figure 7. Previous studies have speculated that the concentration of bacteria in the natural environment is not enough to provide sufficient energy for ciliates even if the latter are capable of ingesting them Fenchel, ; Rassoulzadegan and Etienne, ; Capriulo and Carpenter, ; Jonsson, ; Fenchel and Jonsson, , and have therefore assumed that bacteria are not the main source of prey for ciliates Kamiyama, However, bacterial concentrations in coastal waters and lakes are high enough to provide ciliates with sufficient energy for growth Sherr et al.
In the open ocean, the low biomass of bacteria may not be enough to support the growth of ciliates, whose dietary carbon mainly comes from grazing on nano-sized plankton. However, in the coastal zone and especially in culture, carbon obtained from grazing on bacteria should be taken into account.
Ophelia 5 , — Structure and function of the benthic ecosystem. Ophelia 6 , 1— Hydrobiologia 46 , — Small: Structure and function of the oral cavity and its organelles in the hymenostome ciliate Glaucoma.
Ferguson, R. Rublee: Contribution of bacteria to standing crop of coastal plankton. Finlay, B. Oecologia Berl. Freshwater Biol. Heinbokel, J. Grazing and growth rates in laboratory cultures. Grazing rates of field populations. Beers: Studies on the functional role of tintinnids in the Southern California Bight. Grazing impact of natural assemblages. Handbook of Nutrition and Food, Sect. CRC Press, Cleveland in press.
Laybourn, J. Finlay: Respiratory energy losses related to cell weight and temperature in ciliated protozoa. Oecologia Beri. Stewart: Studies on consumption and growth in the ciliate Colpidium campylum Stokes. Porter, K. Pace, and J. Battey: Ciliate protozoans as links in freshwater planktonic food chains.
Nature , — Article PubMed Google Scholar. For ingestion of diatoms, desmid Closterium and Arcella, the mechanisms involving ciliary action alone were sufficient for ingestion, since these preys are smaller than the ciliate under study. The autecological data registered for F. Os dados de auto-ecologia registrados para F. Feeding behavior of Frontonia leucas Ehrenberg Protozoa, Ciliophora, Hymenostomatida under different environmental conditions in a lotic system. E-mail: rjuniodias yahoo.
For ingestion of diatoms, desmid Closterium and Arcella , the mechanisms involving ciliary action alone were sufficient for ingestion, since these preys are smaller than the ciliate under study. Frontonia leucas Ehrenberg, is found in running and stagnant water throughout the year, living in sediments at depths of up to five centimeters, and also in plankton.
Although it forms resting cysts, there are no reports of its occurrence in terrestrial habitats. It is rare in marshlands, estuaries and sewage treatment plants. DEVI reported cannibalism in this species. The most important characteristic in identifying F. GOLDSMITH observed alterations in its original oval body shape according to the food ingested and the various mechanisms involved in ingesting desmids and cyanobacteria.
Frontonia leucas is included in the saprobic system, indicating environments that range from betamesosaprobic to alphamesosprobic. Because it is a eurythermic, euryoxibiontic and omnivorous species, it can be found in diverse environments and tolerates wide variations of physical and chemical parameters FOISSNER et al.
The objective of this study was to record and describe the morphological changes and the ingestion mechanisms of F. We obtained sediment samples using mL beakers. We then took the samples to the laboratory, placed them in Petri dishes and examined them under a stereoscopic microscope. We selected the specimens of F. We then prepared cultural media of the specimens containing filtered water from each collection point and the types of food observed inside them cyanobacteria, diatoms, desmids and testate amoebas.
To observe the morphological changes and the ingestion mechanisms in vivo , we selected specimens of F. We monitored the physical and chemical qualities of the water at each collection point with portable equipment, recording the dissolved oxygen concentration, pH, conductivity and water temperature. Statistical treatment of the physical and chemical data was by multivariate distance analysis Euclidean distance. We observed the ciliates of F. This work presents the first report of the ingestion of testate amoebas of the genus Centropyxis by F.
Blaise W. Corotto , University of North Georgia Follow. Ciliates also feed via phagocytosis, but instead of enveloping particles the way amoebae do, ciliates take up particles through a complex, permanent, funnel-shaped feeding apparatus.
It is unclear whether receptor-ligand interactions are needed to trigger the process. The literature includes few reports of such selectivity in ciliates. To further investigate this issue, we chose to study feeding selectivity in the ciliate Tetrahymena pyriformis Ehrenberg,
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