Laboea Strobila Research Articles

In situ imaging of a kleptoplastidic ciliate thin layer indicates traditional sampling underestimates oceanic mixotroph biomass

Planktonic mixotrophs, including ciliates, are abundant, yet understudied, mediators of primary and secondary production in aquatic food webs. Here, we report high-resolution in situ observations of a thin layer—a vertically limited patch of high organism abundance—of the ciliate, Laboea strobila. Within the thin layer, peak L. strobila abundances were as high as 62,000 cells/L, six times higher than previously reported, and were strongly positively correlated with co-measured chlorophyll a concentrations, indicating that the organism indulged in kleptoplasty, retaining plastids from ingested algae. Estimates indicated L. strobila contributed to ~63–78% of chlorophyll a within the layer, in sharp contrast to conventional expectations that phytoplankton dominate this signature, suggesting that mixotroph biomass, and consequently, their contribution to marine ecosystems is widely underestimated. These observations also highlight the importance of pairing traditional approaches such as chlorophyll a measurements with high-resolution imaging for proper attribution of biomass proxies.

Spring Distribution of Ciliate Plankton in the Southeastern Yellow Sea in 2019

As planktonic ciliates have been recognized as important players in marine microbial food webs, relevant studies have been conducted in the western coastal waters of the Yellow Sea. However, little is known about ciliate distributions from the eastern coast of the Yellow Sea near the Korean Peninsula. A spring cruise in April 2019 was carried out to investigate vertical and horizontal distributions of ciliate plankton at 18 stations that form three zonal sections in the eastern area. Biological (picoplankton, nanophytoplankton, and mesozooplankton) and hydrological (water temperature and salinity) environments were also analyzed to understand relationships between the ciliate distributions and the environments. High abundance (ca. 2400 cells L−1) of a large ciliate species, Laboea strobila, was observed at the surface water of Stn. 37–5. Abundance peak of large (> 50 μm) ciliates coincided with the peak of mesozooplankton abundance. Spatial distribution of the large ciliates was associated with nanophytoplankton distribution while a smaller (20–50 μm) ciliate group was associated with picoplankton distribution. Therefore, the spring distribution of ciliate plankton in the southeastern coast of the Yellow Sea indicates that food size for the ciliates is one of the important factors controlling ciliate compositions as well as their abundances. Further investigations need to be carried out to understand seasonal differences of ciliate distributions in the eastern Yellow Sea.

Kapıdağ Yarımadası’nın (Marmara Denizi) İki Körfezinde Siliyatların Çevresel Parametrelere Göre Dağılımı

This study was carried out seasonally in order to determine the environmental variables affecting the ciliate species and their distribution in Gulfs of Erdek and Bandırma by using three stations in each gulf between 2006 and 2008. At the end of the study, a total of 14 ciliates taxa were identified, but three of them were the genus level. Epiplocyloides sp., Proplectella ovata, Laboea strobila and Tiarina fusus species identified are the new records for the Sea of Marmara. The maximum number of species belonged to the Choreotrichida ordo with 11 taxa. The Choreotrichida ordo showed the highest diversity in summer season. The ecological data used in this study were obtained from the previous study concurrently conducted in the same region. According to the Spearman’s rank-correlation, it was determined that the salinity, DO, Chl-a and NO3+NO2-N levels affected the distribution of the ciliates and the salinity was increased and species abundance was decreased based on the rise in depth. The highest similarity between the stations was observed in stations 2 and 3 in the Gulf of “Bandırma at a depth of 0.5 m (96.5%) and all the depths of the stations were found to be 23.6% similar.

The genetic diversity of plastids associated with mixotrophic oligotrich ciliates

AbstractMixotrophic oligotrich ciliates use plastids sequestered from algal prey to acquire energy and metabolic products from photosynthesis. We isolated mixotrophic oligotrichs from coastal waters off Massachusetts (MA) and California (CA), as well as from two freshwater ponds in MA, and identified associated plastid 23S rRNA genes. Ciliates were identified using a combination of microscopy and 18S rRNA phylogeny, and included Laboea strobila and various Pseudotontonia, Spirotontonia, and Strombidium species from marine waters, and Limnostrombidium viride from freshwater. Overall, nearly half of all plastid sequences recovered from ciliates were haptophytes, followed by 15–20% for stramenopiles and chlorophytes, and < 10% originating from cryptophyte algae. No plastid sequences were from dinoflagellates. Cells of Strombidium ‘biarmatum’ collected from coastal MA in spring and fall possessed mostly Micromonas plastids, but during spring also possessed cryptophyte sequences. During spring, L. strobila were found to have a mix of chlorophyte, cryptophyte, haptophyte, and stramenopile sequences, while a co‐occurring Strombidium sp. had mostly chlorophyte and haptophyte sequences. Mixotrophic Pseudotontonia and Spirotontonia spp. were sampled during summer from coastal MA and in Monterey Bay, CA, and cells from both populations were dominated (> 70%) by haptophyte plastids of similar phylogenetic origin. L. viride were also evaluated from two freshwater ponds and possessed mostly Chrysochromulina sp. (haptophyte) and synurid (stramenopile) sequences. These results are the first survey of the genetic diversity of plastids associated with pelagic mixotrophic oligotrich ciliates and suggest that some species may selectively retain plastids from certain algal groups, while others appear to be generalists.

Differences in planktonic ciliate spatial distribution in spring and autumn in the southern Yellow Sea

Seasonal variation of marine plankton spatial distribution is important in understanding the biological processes in the ocean. In this study, we studied spatial distribution of planktonic ciliate abundance and biomass in the central deep area (station depth greater than 60 m) and the coastal shallow area (station depth less than 60 m) of the southern Yellow Sea (32°–36.5°N, 121°–125°E) in spring (April) and autumn (October–November) of 2006. Our results showed that both ciliate abundance and biomass in the surface waters were higher in spring ((1 490±2 336) ind./L; (4.11±7.81) μg/L) than in autumn ((972±823) ind./L; (1.11±1.18) μg/L, calculated by carbon). Ciliate abundance and biomass in the surface waters of the coastal shallow area were similar in spring and autumn. However, in the central deep area, those values were much higher in spring ((1 878±2 893) ind./L; (5.99±10.10) μg/L) than in autumn ((738±373) ind./L; (0.74±0.76) μg/L). High values of ciliate abundance and biomass occurred in the central deep area in spring and in the coastal shallow area in autumn. Mixotrophic ciliate Laboea strobila was abundant in the central deep area in spring, when a phytoplankton bloom occurred. However, in autumn, L. strobila was abundant in the coastal shallow area. Boreal tintinnid Ptychocyli obtusa was found in spring. Both L. strobila and P. obtusa were concentrated in the surface waters when their abundance was more than 1 000 ind./L. Peaks of these species were in the subsurface waters when their abundance was less than 400 ind./L. This study showed that both high abundance and biomass of ciliates occurred in different areas in southern Yellow Sea seasonally.

Using ciliates to monitor different aquatic environments in Daya Bay, South China Sea

Spatial patterns of planktonic ciliate communities were studied to monitor marine water quality during winter, spring, summer, and autumn of 2014 in Daya Bay, South China Sea. A total of 41 species, with eight dominant species, were identified. Multivariate and univariate analyses demonstrated that spatial taxonomic pattern of planktonic ciliate communities was significantly correlated with environmental condition; ciliate abundance, species diversity, and species richness were significantly correlated with NO3– and salinity or temperature. Additionally, two dominant species (Tintinnopsis minuta Wailes, 1925 and Tintinnopsis beroidea Stein, 1867) were significantly positively correlated with nutrients, particularly with nitrogen nutrients. Three dominant species (Strombidium conicum (Lohmann, 1908) Wulff, 1919; Spirotontonia turbinata (Song & Bradbury, 1998) Agatha, 2004; Laboea strobila Lohmann, 1908) showed more sensitivity to salinity, whereas Mesodinium rubrum (Lohmann, 1908) was significantly correlated with temperature. Our findings suggest that planktonic ciliate communities can be considered a favorable bioindicator of marine water quality.

自然海区混合营养浮游鞭毛虫和纤毛虫生态学

海洋浮游生物的混合营养是指一种生物既能进行光合自养，又能进行摄食营养。混合营养使得这种生物既是生产者，又是消费者，因此对传统的食物链和生态模型研究是个挑战。混合营养的海洋浮游生物在自然海区的分布是理解它们在自然海区生态功能的基础，本文综述了自然海区混合营养浮游生物的重要类群--鞭毛虫和纤毛虫的计数方法和结果。混合营养鞭毛虫在不同海区占含色素鞭毛虫的比例多小于50%。混合营养寡毛类纤毛虫的种类大约十余种，其中球果螺体虫(Laboea strobila)是混合营养纤毛虫的重要类群，多分布在温带和极地海区;不同海区混合营养纤毛虫丰度和生物量所占比例多低于70%。总体来看，混合营养型海洋浮游生物生态特征在自然海区的研究较少，我国在这方面的研究才刚起步。 Mixotrophic microplankton are those that can carry out photosynthesis and ingestive behavior simultaneously. Mixotrophy makes mixotrophic microzooplankton be producer and consumer. Thus it’s a challenge for traditional phytoplankton-zooplankton dichotomy and the study of eco-logical model. The distribution of mixotrophic microzooplankton in the sea is the foundation to understand their ecological function. In this study, we summarized the counting method and the result of mixotrophic flagellate and ciliate in the sea in previous studies. For mixotrophic flagellate, its percentage of abundance in flagellate with plastid in different sea regions was mostly less than 50%. Taxonomically, more than ten mixotrophic ciliates species were identified up to now. As the most easily identified mixotrophic ciliates, Laboea strobila mainly appeared in temperate zone and polar sea region. Percentage of mixotrophic ciliates abundance and biomass in different sea regions was mostly less than 70%. Overall, the research about taxonomy and ecology of mixotrophic flagellate and ciliate in natural sea region was scarcely carried out. In China the knowledge gap of mixotrophic microzooplankton has been indentified and is being focused on in some related research.

Planktonic Microbes in the Gulf of Maine Area

In the Gulf of Maine area (GoMA), as elsewhere in the ocean, the organisms of greatest numerical abundance are microbes. Viruses in GoMA are largely cyanophages and bacteriophages, including podoviruses which lack tails. There is also evidence of Mimivirus and Chlorovirus in the metagenome. Bacteria in GoMA comprise the dominant SAR11 phylotype cluster, and other abundant phylotypes such as SAR86-like cluster, SAR116-like cluster, Roseobacter, Rhodospirillaceae, Acidomicrobidae, Flavobacteriales, Cytophaga, and unclassified Alphaproteobacteria and Gammaproteobacteria clusters. Bacterial epibionts of the dinoflagellate Alexandrium fundyense include Rhodobacteraceae, Flavobacteriaceae, Cytophaga spp., Sulfitobacter spp., Sphingomonas spp., and unclassified Bacteroidetes. Phototrophic prokaryotes in GoMA include cyanobacteria that contain chlorophyll (mainly Synechococcus), aerobic anoxygenic phototrophs that contain bacteriochlorophyll, and bacteria that contain proteorhodopsin. Eukaryotic microalgae in GoMA include Bacillariophyceae, Dinophyceae, Prymnesiophyceae, Prasinophyceae, Trebouxiophyceae, Cryptophyceae, Dictyochophyceae, Chrysophyceae, Eustigmatophyceae, Pelagophyceae, Synurophyceae, and Xanthophyceae. There are no records of Bolidophyceae, Aurearenophyceae, Raphidophyceae, and Synchromophyceae in GoMA. In total, there are records for 665 names and 229 genera of microalgae. Heterotrophic eukaryotic protists in GoMA include Dinophyceae, Alveolata, Apicomplexa, amoeboid organisms, Labrynthulida, and heterotrophic marine stramenopiles (MAST). Ciliates include Strombidium, Lohmaniella, Tontonia, Strobilidium, Strombidinopsis and the mixotrophs Laboea strobila and Myrionecta rubrum (ex Mesodinium rubra). An inventory of selected microbial groups in each of 14 physiographic regions in GoMA is made by combining information on the depth-dependent variation of cell density and the depth-dependent variation of water volume. Across the entire GoMA, an estimate for the minimum abundance of cell-based microbes is 1.7×1025 organisms. By one account, this number of microbes implies a richness of 105 to 106 taxa in the entire water volume of GoMA. Morphological diversity in microplankton is well-described but the true extent of taxonomic diversity, especially in the femtoplankton, picoplankton and nanoplankton – whether autotrophic, heterotrophic, or mixotrophic, is unknown.

Community structure and trophic role of ciliates and heterotrophic nanoflagellates in Rhone River diluted mesoscale structures (NW Mediterranean Sea)

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 57:263-277 (2009) - DOI: https://doi.org/10.3354/ame01339 AME Special: 'Rassoulzadegan at Villefranche-sur-Mer: 3 decades of aquatic microbial ecology' Community structure and trophic role of ciliates and heterotrophic nanoflagellates in Rhone River diluted mesoscale structures (NW Mediterranean Sea) Urania Christaki1,*, Claude Courties2, Fabien Joux3, Wade H. Jeffrey4, Jacques Neveux3, Jean-Jacques Naudin3 1Univ Lille Nord de France, ULCO, LOG, CNRS, UMR 8187, 32 Avenue Foch, 62930 Wimereux, France 2UMPC Univ Paris 06, FRE 3247, MBCE, CNRS, Observatoire Océanologique, 66651 Banyuls-sur-mer, France 3UMPC Univ Paris 06, FRE 3247, MBCE, LOBBCNRS, UMR 7621, Observatoire Océanologique, 66651 Banyuls-sur-mer, France 4Center for Environmental Diagnostics and Bioremediation, 11000 University Parkway, University of West Florida, Pensacola, Florida 32514, USA *Email: urania.christaki@univ-littoral.fr ABSTRACT: Studies of the Rhone River plume, and in particular its diluted mesoscale structures, have shown over recent years that low salinity water (LSW) is characterised by both high primary and high secondary productivity. Here we compare the structure and grazing activity of the hetorotrophic community (nanoflagellates, ciliates) in the LSW and the surrounding marine water (MW) of the northwestern Mediterranean Sea. Furthermore, we report on the temporal variability of these characteristics all along a Lagrangian track in the LSW. In May 2006, salinity of the LSW ranged from 31.41 to 38.25 down to a depth of 35 m, and surface chlorophyll a concentration reached 15.5 µg l–1. The ciliate community structure was similar in both the LSW and the MW, characterised by the dominance of the mixotrophic ciliates Laboea strobila and Myrionecta rubra. The ciliate biomass was approximately 6 times greater in the LSW, compared to the MW. This difference was due to the mixotrophic ciliates, which were about 4- to 5-fold more important in terms of abundance and biomass in the LSW, while heterotrophic ciliates only increased by a maximum of 2-fold. M. rubra was the most abundant species reaching 4600 cells l–1, while L. strobila was dominant in terms of biomass, accounting for 47% of total biomass in the LSW. Ciliates, in particular mixotrophs, were very active in the LSW where they grazed on phytoplankton at rates near their maximum clearance capacities. Mixotrophic and heterotrophic ciliates in LSW consumed about 50 and 10% of the nanophytoplankton stock per day, respectively. The mixotrophic ciliate L. strobila was found to be an efficient grazer of nanophytoplankton. In contrast to the ciliates, the biomass of heterotrophic nanoflagellates was similar in both the LSW and the MW; thus, we suggest that the transfer of bacterial biomass in the LSW towards higher trophic levels was moderate. KEY WORDS: Bacterivory · Grazing · Mixotroph · Laboea strobila · Picoeucaryotes · Rhone River plume Full text in pdf format PreviousNextCite this article as: Christaki U, Courties C, Joux F, Jeffrey WH, Neveux J, Naudin J (2009) Community structure and trophic role of ciliates and heterotrophic nanoflagellates in Rhone River diluted mesoscale structures (NW Mediterranean Sea). Aquat Microb Ecol 57:263-277. https://doi.org/10.3354/ame01339 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 57, No. 3. Online publication date: November 24, 2009 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2009 Inter-Research.

Importance and nutritional value of large ciliates for the reproduction of Acartia clausi during the post spring-bloom period in the North Sea

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 50:261-277 (2008) - DOI: https://doi.org/10.3354/ame01168 Importance and nutritional value of large ciliates for the reproduction of Acartia clausi during the post spring-bloom period in the North Sea Jörg Dutz1,3,*, Janna Peters2 1Department of Biological Oceanography, Institute for Baltic Sea Research Warnemünde, Seestraße 15, 18119 Rostock, Germany 2Department of Marine Zoology, University of Bremen, PO Box 330440, 28334 Bremen, Germany 3Present address: Department of Marine Ecology and Aquaculture, Danish Institute for Fisheries Research, Kavalergården 6, 2920 Charlottenlund, Denmark *Email: jdu@difres.dk ABSTRACT: Shipboard experiments were performed to examine the qualitative importance of large marine microzooplankton for the reproduction of Acartia clausi in the North Sea. Feeding and egg production were compared in 2 treatments in which females were fed natural seston or natural seston selectively enriched with large prey (>20 µm). The mineral (C, N) and lipid contents of the food suspensions were determined for size-fractionated samples to characterize the nutritional composition of prey. Large oligotrich ciliates and Strobiliidae dominated the seston biomass. Ciliates, particularly the oligotrich Laboea strobila, were the preferred food and made up more than 86% of the diet (2.9 µg C female-1 d-1) in the natural treatment. Small thecate dinoflagellates composed the remaining part. Egg production was high (>25 eggs female-1 d-1), achieving maximum rates recorded for this species in the North Sea. Ingestion and egg production of females increased equally in the enriched treatment, largely due to ingestion of additional ciliates. This allowed calculation of the gross growth efficiency for egg production on a diet of mixed ciliates, which was high at ~30%. Measurements of the mineral and lipid content confirmed a high seston nutritional quality. The 20 to 48 µm fraction reflected the composition of female diets and indicated an enrichment of N and polyunsaturated fatty acids (PUFA) in the diet compared to total seston. The fraction >48 µm consisted mostly of ciliates (>97%) and was particularly important in providing N to copepods. Ciliates were also rich in PUFA and eicosapentaenoic acid (EPA), which is normally characteristic of diatoms. We conclude that large ciliates constitute an excellent food source for the reproduction of A. clausi. The occurrence of biomass peaks of large ciliates following the spring diatom bloom probably contributes substantially to the spring recruitment of the species in the North Sea. KEY WORDS: Acartia clausi · Feeding · Egg production · Ciliates · Laboea strobila · Biochemical composition · Polyunsaturated fatty acids · North Sea Full text in pdf format PreviousNextCite this article as: Dutz J, Peters J (2008) Importance and nutritional value of large ciliates for the reproduction of Acartia clausi during the post spring-bloom period in the North Sea. Aquat Microb Ecol 50:261-277. https://doi.org/10.3354/ame01168 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 50, No. 3. Online publication date: March 26, 2008 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2008 Inter-Research.

Use of species‐specific primers and PCR to measure the distributions of planktonic ciliates in coastal waters

We developed a method to extract environmental DNA and amplify target portions of the internal transcribed spacer region (ITS) of the ribosomal gene (ITS1‐5.8S‐ITS2) from individual species of oligotrich and choreotrich ciliate microzooplankton. To date, we have lab‐ and field‐tested primers specific to the tintinnid Favella ehrenbergii, the oligotrich Laboea strobila, and the choreotrich Strombidinopsis sp. For all three species, the primers were both species‐specific (not producing PCR product from non‐target DNA) and comprehensive (able to amplify from different populations of the target species). The method is both time‐efficient and sensitive, compared with microscopy. In seawater samples amended with both target and non‐target DNA, we were able to detect the targets at < 1 cell L−1. Some difficulties we encountered resulted from PCR‐inhibitory compounds that co‐extracted with the environmental DNA, and the rarity of the target DNA within natural plankton assemblages. Comparisons with microscopic counts were qualitatively similar to PCR (presence/absence of the species in different amounts of extract). We are evaluating ways to make the method fully quantitative by investigating the degree to which copy number for this gene may vary among individuals.

Microbial assemblage during the spring‐summer transition on the northeast continental shelf of New Zealand

The northeast shelf of the North Island of New Zealand was sampled on four occasions from early spring to late summer in 1996–97. During this period, tight linkages between the physical and chemical forcings and the response from the microbial food‐web were observed. During bloom conditions in early spring the phytoplankton population was dominated by large diatoms with the picophytoplankton contributing an average of 8% of the phytoplankton biomass. The picophytoplankton fraction increased to contribute a mean of 57% of the phytoplankton biomass in late summer when upwelling had ceased, the water column was strongly stratified and dissolved inorganic nitrogen concentrations were negligible. The changes in the phytoplankton assemblage were accompanied by changes in the microzooplankton population. In early spring the microzooplankton population was dominated by larger species, including copepod nauplii and >20 μm aloricate ciliates, with copepod nauplii contributing up to 50% of the microzooplankton biomass in early and late spring. Peak microzooplankton biomasses of 880–2093 μg C m‐2 in the mixed layer occurred in early and late spring, depending on the station. The large ciliate Laboea strobila was an important component of the microzooplankton biomass, and increased substantially at three out of the five stations between early and late spring. Strong upwelling in early summer resulted in substantial decreases in picophytoplankton and microzooplankton abundance. In late summer the composition of microzooplankton population had changed substantially, with the <20 μm aloricate ciliates increasing from 35 to 90% of the total biomass. The overall increase in the importance of the microbial components of the food‐web between early spring and late summer was closely linked with changes in the physical and chemical drivers of the system.

Reframing the ‘Everything is everywhere’ debate: evidence for high gene flow and diversity in ciliate morphospecies

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 41:55-65 (2005) - doi:10.3354/ame041055 Reframing the ‘Everything is everywhere’ debate: evidence for high gene flow and diversity in ciliate morphospecies Laura A. Katz1, 2, *, George B. McManus3, Oona L. O. Snoeyenbos-West1, 5, Autumn Griffin1, Katarzyna Pirog1, Barbara Costas3, Wilhelm Foissner4 1Department of Biological Sciences, Smith College, College Road, Northampton, Massachusetts 01063, USA2Program in Organismic and Evolutionary Biology, University of Massachusetts-Amherst, 611 N. Pleasant Street, Amherst, Massachusetts 01003, USA3Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Rd., Groton, Connecticut 06340, USA4Institut für Zoologie, Universität Salzburg, Hellbrunnerstr. 34, 5020 Salzburg, Austria5Present address: Dept of Plant, Soil and Insect Sciences, Fernald Hall, UMASS Amherst, Amherst, Massachusetts 01003, USA *Email: lkatz@smith.edu ABSTRACT: Current debate on microbial diversity contrasts the ‘cosmopolitan’ hypothesis, which argues for high gene flow and low diversity, with the ‘endemism’ hypothesis, which argues for high diversity and geographically restricted gene flow. Our analyses of genetic variation in ciliate morphospecies isolated from ephemeral environments (freshwater ponds and tide pools) redefine this debate. In 2 different clades of oligotrich ciliates (in the genera Halteria/Meseres and Strombidium), we found both high levels of diversity and evidence of high gene flow as indicated by the presence of identical haplotypes across broad geographic ranges. Five recognizable morphospecies of Halteria/Meseres were found to be composed of 7 different clades, differing by as much as 7.6% sequence divergence at the ITS locus (ITS1, ITS2 and 5.8S rDNA). Two recognizable morphospecies of Strombidium (S. oculatum and S. stylifer) resolved into 10 distinct clades, differing by as much as 15.7% at the same locus. For both groups of ciliates, the genetic divergence underlying these morphospecies may be related to cycles of isolation in their ephemeral habitats (freshwater lakes and ponds for Halteria/Meseres and tide pools for Strombidium). By comparison, there is both low diversity and highgene flow in published data on ciliates from open coastal water (Laboea strobila and several species of tintinnids), a more stable environment over evolutionary time-scales. Our analyses indicate that models of microbial diversity must test for ecologically driven patterns in the interactions of gene flow and species richness to account for observed patterns of high dispersal and high gene flow. KEY WORDS: Ciliate phylogeography · Endemism · Cosmopolitanism · Gene flow · Cryptic species Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 41, No. 1. Online publication date: November 11, 2005 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2005 Inter-Research.

New observations on the tontoniid ciliate Spirotontonia grandis (Suzuki and Han, 2000) Agatha, 2004 (Ciliophora, Oligotrichida, Tontoniidae); comparison with the similar Laboea strobila

Spirotontonia grandis (Suzuki and Han, 2000) Agatha, 2004 belongs to the family Tontoniidae Agatha, 2004 because it has a contractile tail. It is the type of the genus Spirotontonia Agatha, 2004, which is characterized by a sinistrally spiralled girdle kinety. Supplementary observations on protargol-impregnated and, especially, live specimens of S. grandis from the Irish Sea are provided. These new findings are included in an improved species diagnosis. Furthermore, they contribute to a better separation of the tontoniid S. grandis from the strombidiid Laboea strobila, which also has a screw-like appearance, a sinistrally spiralled girdle kinety, and multiple macronuclear nodules, but lacks the tontoniid tail. Since the tail of S. grandis, the main distinguishing feature between the two species, is highly contractile and easily lost, further differences are emphasized, e.g., the lower number of girdle kinety whorls (3.0–3.5 vs. 4.5–5.0), the larger cell size (∼110–170×55–80 μm vs. ∼80–110×40–60 μm after protargol impregnation), the relatively larger size of the ventral portion of the membranellar zone (∼51% vs. ∼40% of body length), and the overlapping cortical platelets (present vs. absent). The record of S. grandis from the Irish Sea is the first record outside the East China Sea and the second worldwide.

Morphologic and genetic variability in the marine planktonic ciliate Laboea strobila Lohmann, 1908 (Ciliophora, Oligotrichia), with notes on its ontogenesis.

Laboea strobila Lohmann, 1908 is a conspicuous oligotrich ciliate in the marine plankton. In order to compare different populations, the morphology of specimens from the Mediterranean Sea, North Sea, and Irish Sea was investigated using live observation, protargol impregnation, and scanning electron microscopy. Furthermore, the PCR-amplified products of the SSrRNA gene from a monoclonal culture of L. strobila from the Mediterranean Sea were sequenced and aligned with sequences of other oligotrichs, including a population of L. strobila from the Atlantic coast of the USA. Finally, the data from the ecological literature were summarized and the cultivation methods were described. The SSrRNA gene sequences of the two distantly located L. strobila populations from the North Atlantic are identical. Likewise, the morphometrics of most populations so far investigated after protargol impregnation (i.e. from the North Atlantic) do not show obvious differences. In all computed phylogenetic trees, L. strobila groups with Strombidium species, forming a monophyletic taxon corresponding to the subclass Oligotrichia. These results are corroborated by the ontogenetic comparison. Since no type species was fixed for Laboea Lohmann, 1908, L. strobila was designated in the present paper.

Spatial distribution of ciliates, copepod nauplii and eggs, Engraulis japonicus post-larvae and microzooplankton herbivorous activity in the Yellow Sea, China

The abundance of anchovy Engraulis japonicus larvae, >20 mum ciliates, copepod eggs and nauplii, and microzooplankton herbivorous activity were studied in the Yellow Sea in June 2000. Anchovy juveniles and larvae were found in only 6 of the 19 stations sampled. The ciliate communities were dominated by 2 species: Laboea strobila and Strombidium compressum. In the surface waters, the abundance of L. strobila ranged between 0 and 560 ind. l(-1). S. compressum only appeared at Stns 15 to 18 (20 to 3300 ind. l(-1)). L. strobila was found mainly in the top 20 m. The abundance of L. strobila was less than 50 ind, l(-1) in waters deeper than 25 m. S, compressum showed subsurface abundance peaks at the salinity abnormality. Tintinnids occurred occasionally with abundance lower than 100 ind. l(-1), The total ciliate abundance fell in the range of 40 to 3420 ind. l(-1). The ciliate biomass in the surface water and the water column ranged between 0,15 and 6.76 mug C l(-1) and 0.4 and 134.4 mg C m(-2), respectively, In the surface waters, the abundance of copepod eggs and nauplii ranged from 0,3 to 3.1 and 1,1 to 15.6 ind, l(-1), respectively. The average abundance of copepod eggs and nauplii in 4 depth (0, 5, 10 and 20 m) fell in the range of 0.2 to 2.8 and 1.0 to 29.4 ind. l(-1), respectively. As a food item of the E. japonicus post-larvae, the abundance of copepod nauplii and eggs appeared to be low. The abundance peaks of ciliate and E, japonicus post-larvae coincided. Although not found in the gut of E, japonicus post-larvae, aloricate ciliates might be ingested by first-feeding anchovy larvae, preventing initial starvation and prolonging the time to irreversible starvation. On the basis of dilution experiments with positive microzooplankton grazing rates, microzooplankton grazed at rates of 0 to 0.61 d(-1). Grazing pressure of microzooplankton on chlorophyll a standing stock (P-i) and potential chlorophyll a primary production (P-p) were 17 to 46% and 35 to 109% d(-1), respectively.

Seasonal variations of photosynthetic ciliates at a Mediterranean coastal site

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 23:163-175 (2001) - doi:10.3354/ame023163 Seasonal variations of photosynthetic ciliates at a Mediterranean coastal site M. Modigh* Stazione Zoologica ŒA. Dohrn¹, Villa Comunale, 80121 Naples, Italy *E-mail: modigh@alpha.szn.it ABSTRACT: Standing stocks of ciliated protozoa were analyzed in weekly samples over 3 yr at a Mediterranean coastal site (Gulf of Naples, Tyrrhennian Sea). Photosynthetic ciliates contributed 49% of total ciliate biomass; heterotrophic naked choreotrichs and tintinnids contributed 25 and 16%, respectively. The present paper focuses on the occurrence and succession of the autotrophic ciliate Mesodinium rubrum and of aloricate mixotrophic and heterotrophic choreotrichs. A very diverse assemblage of Strombidium spp. dominated the mixotrophic choreotrich populations, while Tontonia spp. contributed 14.3% and Laboea strobila 4.7% to plastidic ciliate abundance. The annual pattern of occurrence of these 3 genera of mixotrophic ciliates was similar over the 3 years of this study. Autotrophic and mixotrophic ciliates differed in the periods of maximum relative contribution to the ciliate assemblage. Mixotrophic choreotrichs dominated the ciliate populations in spring and summer while the maximum contribution of autotrophic ciliates occurred in winter. M. rubrum occurred in 2 forms‹the larger form was the only Mesodinium observed in winter, while it was absent during summer, when the smaller Mesodinium was at times observed. The contribution of M. rubrum to annual primary production in the Gulf of Naples was about 3%. Aloricate choreotrich populations were dominated by small cells; 92% of the aloricate heterotrophs were <30 μm equivalent spherical diameter (ESD), and for the mixotrophic ciliates 73% were <30 μm ESD and 24% were between 30 and 50 μm ESD. Notwithstanding a very wide range of variation in aloricate choreotrich densities, 135 to 48800 cells l-1, the relative contribution of different size classes was remarkably stable at any level of abundance. The calculated production for aloricate choreotrichs was between 2.3 and 3.3 g C m-3 yr-1 for the surface layer, about 50% of which was estimated to rely on ciliate grazing of bacterio- and picoplankton, as well as on photosynthesis covering, in part, the carbon demand of mixotrophic ciliates. KEY WORDS: Planktonic ciliates · Mixotrophic choreotrichs · Mesodinium rubrum · Mediterranean coastal site Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 23, No. 2. Online publication date: January 31, 2001 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2001 Inter-Research.

Annual succession of marine pelagic protozoans in Disko Bay, West Greenland, with emphasis on winter dynamics

The succession of pelagic ciliates and heterotrophic dinoflagellates was investigated in Disko Bay, West Greenland, from April 1996 to June 1997. In terms of biomass they contributed equally. Their annual distribution was bimodal with maxima in May/June and August. Summer lev- els were similar to those reported at lower latitudes. Winter dynamics were different. Due to 2 mo of polar darkness, food concentrations for ciliates and heterotrophic dinoflagellates were below thresh- old concentrations for growth. Nonetheless, small populations persisted throughout the winter. Both protozoan groups had a concentration of ~0.25 〈 10 3 cells l -1 . The succession patterns showed that all individual species peaked at different times during the summer months. However, diversity of the winter community was not different from that observed during summer. Even in the polar winter, the autotrophic ciliate Myrionecta rubra and the obligate mixotrophic ciliate Laboea strobila were recorded. Different strategies for winter survival of protozoans are discussed.

Plankton community structure and carbon cycling on the western coast of Greenland during the stratified summer situation. II. Heterotrophic dinoflagellates and ciliates

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 16:217-232 (1999) - doi:10.3354/ame016217 Plankton community structure and carbon cycling on the western coast of Greenland during the stratified summer situation. II. Heterotrophic dinoflagellates and ciliates Henrik Levinsen1,*, Torkel Gissel Nielsen1, Benni Winding Hansen2 1National Environmental Research Institute, Department of Marine Ecology and Microbiology, Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark 2Roskilde University, Department of Life Sciences and Chemistry, PO Box 260, DK-4000 Roskilde, Denmark *E-mail: hle@dmu.dk ABSTRACT: The structure and ecological role of protozooplankton (ciliates and heterotrophic dinoflagellates) were studied in Disko Bay, West Greenland, from mid-July to mid-September 1994. Heterotrophic dinoflagellates dominated the protozooplankton biomass. When diatoms formed subsurface blooms, heterotrophic dinoflagellates averaged 70% of the integrated protozooplankton biomass. After the diatoms declined, large heterotrophic dinoflagellates became less abundant. Ciliates followed the same vertical distribution as heterotrophic dinoflagellates. However, in contrast to heterotrophic dinoflagellates, maximum ciliate biomasses developed in surface water after the diatom blooms, when the large copepods (Calanus spp.) migrated to the deeper water. Mixotrophic oligotrich ciliates, mainly Laboea strobila, contributed on average 20% to the integrated ciliate biomass. Growth experiments revealed similar specific maximum growth rates for ciliates and heterotrophic dinoflagellates. Maximum growth rates were allometrically related to cell volume. Ciliates and heterotrophic dinoflagellates appear to be key organisms in the cycling of organic matter in this Arctic pelagic ecosystem. KEY WORDS: Arctic pelagic food web · Protozooplankton structure · Ciliates · Heterotrophic dinoflagellates Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 16, No. 3. Publication date: February 24, 1999 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 1999 Inter-Research.

Seasonal distributions of the photosynthesizing ciliates Laboea strobila and Myrionecta rubra (= Mesodinium rubrum) in an estuary of the Gulf of Maine

Seasonal distributions of the photosynthesizing ciliates Laboea strobila and Myrionecta rubra (= Mesodinium rubrum) in an estuary of the Gulf of Maine