Laboea Strobila Research Articles

Strombidiid ciliates from coastal waters near Kingston Harbour, Jamaica (Ciliophora, Oligotrichia, Strombidiidae)

Fifteen marine strombidiid species were measured and identified after protargol staining of bottle-cast samples collected during an annual study of the ciliate microzooplankton in the Caribbean Sea. Nine of these are described herein as new species. One new species from the genus Tontonia, T. simplicidens sp. nov., is defined, based on the pattern of the girdle and ventral kinety. Six new species of Strombidium, S. bilobum sp. nov., S. eurystomum sp. nov., S. ioanum sp. nov., S. maedai sp. nov., S. pollostomum sp. nov. and S. sphaericum sp. nov. are defined, based on cell size and shape, the arrangement of the oral ciliature, and the nature of the macronucleus. One new strombidiid genus Cyrtostrombidium gen. nov., is defined by the presence of a unique oral ‘basket’ and the absence of the ventral polykinetidal zone. Two species of Cyrtostrombidium, C. longisomum sp. nov. and C. wailesi sp. nov., are distinguished, based on cell size and macronuclear structure. Assemblages of six previously-described strombidiid species, S. constrictum, S. dalum, S. epidemum, S. inclinatum, S. wulffi, and Laboea strobila are also briefly described.

Metabolism of photosynthate in the chloroplast-retaining ciliate Laboea strobila

Metabolism of photosynthate in the chloroplast-retaining ciliate Laboea strobila

An experimentally determined carbon : volume ratio for marine “oligotrichous” ciliates from estuarine and coastal waters

The biomass of marine “oligotri chous” ciliates has often been estimated by measuring the cell volume of preserved samples and converting to units of carbon based on theoretical carbon: volume (C: vol) ratios of 0.07–0.11 pg µm−3. Using laboratory cultures of several strains of Laboea strobila, Strombidium spp., and Strobilidium spiralis, we experimentally derived a C: vol conversion factor of 0.19 pg µm−3 for cells preserved with 2% vol : vol Lugol’s iodine. Cell volume estimates of Lugol’s‐preserved cells averaged 76% of cell volume estimates of Formalin‐preserved cells. Hence a C : vol ratio of 0.14 pg µm−3 applies to Formalin‐preserved cells. Our study indicates that the biomass of oligotrichous ciliates in marine systems has been significantly underestimated by the use of inappropriate C: vol ratios.

Abundance of autotrophic, mixotrophic and heterotrophic planktonic ciliates in shelf and slope waters

During early summer, the density of microplanktonic ciliates in the euphotic zone on Georges Bank (Northwest Atlantic) ranged from 600 to 13 000 cells 1 ' ; in the slope waters to the southeast of the bank, densities ranged from 1900 to 2800 cells 1 ' . Myrionecta rubra, a photosynthetic autotroph ciliate with a reduced algal endosymbiont, numerically comprised an average of 30 % of the microplanktonic ciliate fauna at stations in < 100m depth, but 3 % or less of the ciliate fauna at the deeper stations. Oligotrichous ciliates with chloroplasts are estimated to have contributed 34 O/ O of the ciliate fauna and were abundant at both shallow, unstratified stations on the bank and at deeper, stratified stations on the slope of the continental shelf and in the Gulf of Maine. Overall, about 50 O/O of the ciliates in the euphotic zone contained chlorophyll. At the shallow water stations, 2 species, M. rubra and Laboea strobila (a mixotrophic oligotrich) accounted for over 50 % of the biomass of ciliates with chlorophyll. At an irradiance of 100 pE m % l , M. rubra and L. strobila had photosynthetic rates of 85 and 465pg C fixed c e l l l h l , respectively. During summer, when phytoplankton biomass is low, autotrophic and mixotrophic ciliates may make an important contribution to photosynthesis in the larger size fractions and be an important source of food for larger organisms that rely on high quality, 2 15 to 20 pm food particles.

Taxonomic Descriptions of One New Species and Redescription of Four Species in the Family Strombidiidae (Ciliophora, Oligotrichida)1

ABSTRACT Five ciliate species collected from the Woods Hole area were examined by protargol silver impregnation and scanning electron microscopy. These ciliates have been shown to sequester and use chloroplasts obtained from flagellate prey. One new species, Strombidium chlorophilum, is described. Four other species, Strombidium capitatum (Leegaard, 1915) Kahl, 1932, Strombidium conicum (Lohmann, 1908) Wulff, 1919, Strombidium acutum (Leegaard, 1915) Kahl, 1932, and Laboea strobila Lohmann, 1908, are redescribed. Characters used in describing the Strombidiidae include cell size and shape, anterior and ventral polykinetids, macronuclear shape and size, the kinetid “girdle,” the ventral kinety, the trichites, and the paroral kinety. The rationale for using these characters as taxonomic criteria is discussed.

Photosynthetic pigments in the ciliate Laboea strobila from Long Island Sound, USA

Photosynthetic pigments in the ciliate <i>Laboea strobila</i> from Long Island Sound, USA