Ciliates are important components in planktonic food webs,but our understanding of their community structures in different oceanic water masses is limited.We report pelagic ciliate community characteristics in three seas:the tropical West Pacific,the Bering Sea and the Arctic Ocean.Planktonic ciliate abundance had"bimodal-peak","surface-peak"and"DCM(deep chlorophyll a maximum layer)-peak"vertical distribution patterns in the tropical West Pacific,the Bering Sea and the Arctic Ocean,respectively.The abundance proportion of tintinnid to total ciliate in the Bering Sea(42.6%)was higher than both the tropical West Pacific(7.8%)and the Arctic Ocean(2.0%).The abundance proportion of small aloricate ciliates(10–20μm size-fraction)in the tropical West Pacific was highest in these three seas.The Arctic Ocean had higher abundance proportion of tintinnids in larger LOD(lorica oral diameter)size-class.Proportion of redundant species increased from the Arctic Ocean to the tropical West Pacific.Our result provided useful data to further understand ecology roles of planktonic ciliates in different marine habitats. 相似文献
We studied the distribution of microphytoplankton, ciliates and mesozooplankton in relation to environmental factors in the coastal waters around the Kerkennah Islands. Diatom species were more abundant in winter, representing 74% of the total microphytoplankton abundance, whereas dinoflagellate abundance was higher in summer (58%). Naked ciliates dominated during the winter (73%) and loricate ciliates dominated during the summer (67%). Copepods were the most abundant mesozooplankton group present during the entire period of study, comprising 93%–98% of the total mesozooplankton community. The results indicate that (i) species distribution differed significantly between winter and summer, (ii) environmental factors such as temperature, salinity and nutrients influenced plankton assemblages; and (iii) the highest abundance of several pollution indicator species was due to direct exposure to the polluted coast of Sfax and the effect of tidal asymmetries generating nutrient‐rich inputs from the city. 相似文献
Since sewage treatment plants are most effective in Switzerland, the micro-benthic communities in receiving running waters have changed considerably. From January 1980 to September 1981 the periphyton communities in 13 Swiss streams and rivers were monthly investigated. The NH4-N concentration in these waters varied between 0.015 and 1.0 mg/l. Four typical communities of microorganisms were found:In unpolluted running waters mainly small vagile ciliates were abundant; in slightly polluted waters peritricha (in the presence of bacteria) were found; in moderatly polluted waters peritricha in combination of few hymenostomata and Sphaerotilus could grow when bacteria and some degredable organic material where present; in polluted waters the well-known Spaerotilus-community (after Liebmann) could be found.The microscopic as well as the macroscopic aspect should be considered to qualify the degree of pollution in streams and rivers. 相似文献
Meiobenthos (harpacticoids), microzoobenthos (ciliates) and microphytobenthos (epipelic diatoms and dinoflagellates) were collected during July 1999 using nested sampling at the scales of decimeters, meters and tens of meters. Similarity between samples decreased rapidly with distance for all groups, but unicellular organisms were distributed more heterogeneously at a large scale than meiobenthos. Microspatial (decimeter scale) variations contributed the main part of total variation of harpacticoid abundance, while the large-scale differences were less important. On the contrary, these differences yielded the main variability for ciliates and especially for microalgae. The relative role of temporal variability decreased steadily for the smaller-sized organisms. Stability of spatial structure at multiple scales was estimated by Mantel correlations, Rm, between the successive similarity matrices. For harpacticoids, the results showed intensive and chaotic turnover of microaggregations. For microbenthos, rather high Rm values were found in smaller scales: tens of meters—for ciliates, from meters on—for dinoflagellates, and already from decimeter scale and on—for diatoms. Thus, the general spatial pattern (that is the arrangement of micropatches) was more stable for microbenthos than for meiobenthos. Temporal variability of species structure, in contrast to the spatial one, was highest for the smallest organisms. Correlations between size groups, using both total abundance and species composition, differed for microspatial, meso-spatial or temporal distribution. At the microscale, there were slight but significant negative correlations between harpacticoids and microalgae. Meso-scale distribution of dinoflagellates and diatoms differed significantly due to their different preferences in sediment properties. Ciliates were strongly positively correlated with dinoflagellates. At the microscale, each group had an individual community pattern. At larger scales, species composition of diatoms, ciliates and harpacticoids varied in space in coordination, while dinoflagellates behaved independently. It is hypothesized that body size determines the spatio-temporal scale of the perception of environmental heterogeneity. 相似文献
The periphyton of acid, dystrophic bogs was investigated. Glass-slides were exposed in four different bog lakes about 100 km north of Berlin, Germany, in order to examine the species composition and the annual cycle of the protist community. The annual cycles of the periphyton in bog lakes were comparable to those in other mesotrophic lakes: During the winter months small heterotrophic flagellates (HF) dominated the periphyton community. Besides that bacterivorous ciliates were present as typical pioneer species. At the end of the ice covering, almost exclusively unicellular green algae colonized the slides. In May high abundances of ciliates and choanoflagellates were observed. At the same time, a maximum of species was reached. From August to October peritrich ciliates significantly contributed to the periphyton. Their number decreased when early frosts occurred.
The four investigated bog lakes exhibit very similar species compositions, almost all of the species were present in each of the four lakes. Differences were only distinct concerning the dominance of some protistan groups. The largest deflections, however, occurred not between two lakes, but between two habitats within one lake: The upper 30 cm of the Sphagnum mat comprise two very different protistan communities, determined by a strong vertical zoning. Due to the different light and nutrient conditions, the slides of the upper region exhibited a denser colonization, mainly consisting of autotrophic cryptomonads and vagile ciliates. In contrast to this, the slides of the deeper region were mainly colonized by heterotrophic flagellates and sessile peritrich ciliates. 相似文献
Glass-slides were exposed in four different bog lakes located in great forest areas in Northern Germany, about 100 km north of Berlin, in order to examine the protist community of these dystrophic, acid lakes. Species composition and succession of the periphyton were studied during one year. The four investigated bog lakes exhibit similar species compositions, most of the species were present in each of the four lakes. The periphyton was composed of a great variety of protist species. Specimens of all major flagellated protists and of most of the ciliate taxa were found on the slides. Many of these species are ubiquitous. Some species, however, like the flagellates Spongomonas sacculus, Rhipidodendron huxleyi, Cyathobodo sp., and Pseudodendromonas vlkii as well as the ciliates Ophrydium hyalinum, Leptopharynx costatus, Uroleptus caudatus, and Platyophrya sphagni are found more frequently in acid waters. A regular and common occurrence of these species partly characterizes the acid Sphagnum bogs. Besides that, common species like Bodo spp., Cryptomonas spp., Goniomonas truncata, Chilodonella uncinata, Vorticella sp., and Cyrtolophosis mucicola are represented in the periphyton. Examinations of the testate amoebae in the Sphagnum mats show a very different species composition compared to earlier studies.
The investigated bog lakes revealed mesotrophic conditions. In the upper regions of the Sphagnum mats and in the center of the larger bog lakes, oligotrophic conditions still prevail. The lower regions of the Sphagnum mat and the smaller lakes, however, are influenced by the partly degradation of plants and the run-off water from surrounding land. In comparison to earlier studies, the species composition indicates a beginning eutrophication of the bog lakes. A direct anthropogenic impact can be excluded. 相似文献