Mingzhuang Zhu

An approach to analyzing spatial patterns of planktonic ciliate communities for monitoring water quality in Jiaozhou Bay, northern China.

Spatial patterns of planktonic ciliate communities for assessment of marine environmental status were studied from June 2007 to May 2008 in Jiaozhou Bay, Qingdao, northern China. Ciliate communities were sampled biweekly at five sampling sites with a spatial gradient of environmental stress. Multivariate/univariate analyses demonstrated that: (1) the planktonic ciliate community structures represented significant differences among the five sites; (2) spatial patterns of the ciliate communities were significantly correlated with environmental variables, especially the nutrients nitrate nitrogen (NO₃-N) and soluble reactive phosphates (SRP); (3) five dominant species (e.g., Rimostrombidium veniliae, Strombidium capitatum, Mesodinium pupula and Strombidinopsis acutum) were significantly correlated with nitrogen and/or SRP; and (4) both species richness and species diversity indices were correlated with NO₃-N and salinity. These results suggest that planktonic ciliated protozoa might be used as a robust bioindicator of marine water quality.

An approach to determining the sampling effort for analyzing biofilm-dwelling ciliate colonization using an artificial substratum in coastal waters

A new approach to determining sampling effort for analyzing biofilm-dwelling ciliate colonization was studied in the coastal waters of the Yellow Sea, northern China, from May to June 2010. The optimal sample size for evaluating biofilm-dwelling ciliate colonization increased with shortening exposure time, and can be determined according to the probability of recovering those species with a specified cumulative contribution to communities. More slide-replicates were required at a depth of 3 m than at 1 m to recover equivalent proportions of the ciliate communities. For routine colonization dynamics analyses, 10 slide-replicates (175 cm2) were sufficient to achieve a 95% probability of recovering those species with a cumulative contribution of >90% to the ciliate communities at a depth of 1 m. These results suggest that 10 slide-replicates immersed at a depth of 1 m may be an optimal sampling strategy for analyzing the colonization dynamics of biofilm-dwelling ciliate communities in marine habitats.

Colonization dynamics of periphytic ciliate communities on an artificial substratum in coastal waters of the Yellow Sea, northern China

Colonization dynamics of periphytic ciliate communities were studied in coastal waters of the Yellow Sea, northern China from May to June 2010, using an artificial substratum. Samples were collected at two depths of 1 and 3 m. The temporal patterns of ciliate colonization had similar dynamics and were fitted to the MacArthur–Wilson and logistic models in colonization and growth curves at both depths, respectively. The ciliate communities reached equilibrium in species composition within at least 10-days exposure time. However, they differed in both structural and functional parameters between the two layers, despite similar species composition. The species diversity, evenness, the colonization rate (G) and maximum abundance (Amax) were distinctly higher, but the time for reaching 90% equilibrium species number (T90%) was shorter at the depth of 1 m than those at a deeper layer. Results suggest that it is an optimal strategy to collect the ciliate communities within shorter exposure time at 1 m for ecological research and a monitoring programme in marine ecosystems.

Morphology and morphogenesis of a soil ciliate, Rigidohymena candens (Kahl, 1932) Berger, 2011 (Ciliophora, Hypotricha, Oxytrichidae), with notes on its molecular phylogeny based on small-subunit rDNA sequence data.

The morphology and morphogenesis of the stylonychine hypotrich Rigidohymena candens (Kahl, 1932) Berger, 2011, isolated from garden soil in Qingdao, China, were investigated using live observation and protargol impregnation methods. The Qingdao isolate possesses all diagnostic morphological characters of R. candens. The main events during binary fission are as follows: (i) the proter retains the parental adoral zone of membranelles entirely, whereas the old undulating membranes dedifferentiate into an anlage that gives rise to the leftmost frontal cirrus and the new undulating membranes of the proter; (ii) five streaks of fronto-ventral-transverse cirral anlagen are segmented in the pattern 3 : 3 : 3 : 4 : 4 from left to right, which form two frontal, four frontoventral, one buccal, five ventral and five transverse cirri, respectively; (iii) dorsal morphogenesis is in the typical Oxytricha pattern; (iv) three caudal cirri are formed, one at the posterior end of each of dorsal kineties 1, 2 and 4; and (v) the postoral ventral cirrus V/3 is not involved in primordia formation. The morphological and morphogenetic observations and phylogenetic analyses based on the small-subunit rDNA sequence data support the validity of Rigidohymena Berger, 2011 and its systematic position in the subfamily Stylonychinae.

Are non-loricate ciliates a primary contributor to ecological pattern of planktonic ciliate communities? A case study in Jiaozhou Bay, northern China

The contribution of non-loricate ciliate assemblage to the ecological pattern of a ciliated protozoan community was studied based on a 1-year (June 2007―May 2008) dataset collected from Jiaozhou Bay, northern China. Samples were collected biweekly from five sampling sites. Results showed that: ( 1 ) the non-loricate ciliate assemblages were the primary components and significantly correlated with the total ciliate communities in terms of species number, abundance and biomass; ( 2 ) the ecological pattern of non-loricate ciliate assemblages was significantly related to that of both total ciliate communities and variations in environmental variables; and ( 3 ) spatio-temporal variations in biodiversity (richness, diversity and evenness of species) indices of non-loricate ciliate assemblages were significantly correlated with those of total ciliate communities and the environmental conditions, especially nutrients nitrate nitrogen, nitrite nitrogen and soluble reactive phosphorous. These results suggest that the non-loricate ciliates are a primary contributor to the ecological pattern of total ciliate communities and might be used as a potential bioindicator for bioassessment in marine ecosystems.

Morphology and small-subunit rRNA gene sequences of two novel marine ciliates, Metanophrys orientalis spec. nov. and Uronemella sinensis spec. nov. (Protista, Ciliophora, Scuticociliatia), with an improved diagnosis of the genus Uronemella.

The morphology and infraciliature of two novel marine scuticociliates, Metanophrys orientalis spec. nov. and Uronemella sinensis spec. nov., collected from sandy beaches at Qingdao, China, were investigated using live observation and protargol-staining methods. Metanophrys orientalis spec. nov. is distinguished by the following characteristics: marine habitat and a slender to elongate oval body with pointed anterior end and rounded caudal end, in vivo about 25-50 µm long; buccal field about a quarter to a third of body length; nine or ten somatic kineties with dikinetids approximately in anterior half of body, monokinetids in posterior half; membranelles 1 and 2 almost equal in length and composed of two and three longitudinal rows of kinetids respectively; paroral membrane with zigzag structure extending anteriorly to middle portion of membranelle 2; contractile vacuole pore located at posterior end of somatic kinety 1. The genus Uronemella is redefined as follows: marine form with an elongate-elliptical or inverted pear-shaped body; apical plate conspicuous; buccal field about two-thirds of body length, cytostome subequatorially located; oral apparatus Uronema-like; somatic kineties comprising a mixture of dikinetids and monokinetids. Uronemella sinensis spec. nov. is recognized by having an elongate-elliptical body with truncated apical frontal plate, size in vivo about 25-35 × 15-20 µm, nine or ten somatic kineties, membranelle 1 consisting of two or three basal bodies, contractile vacuole pore at posterior end of somatic kinety 1. This study also compared the small-subunit rRNA gene sequences of these two species with other closely related species to show the sequence divergence, which ranged from 3.53 to 9.60%. Phylogenetic analyses support the contention that the genus Uronemella is monophyletic, while Metanophrys is non-monophyletic.

Temporal distributions of microplankton populations and relationships to environmental conditions in Jiaozhou Bay, northern China

To analyse temporal distributions of microplankton populations and relationships to environmental conditions in marine ecosystems, a dataset of microplankton communities was investigated using a range of statistical methods. A total of 164 microplankton species comprising 100 microalgae and 64 ciliates were identified from 120 samples, respectively. Both planktonic microalga and ciliate assemblages showed temporal patterns and were significantly correlated between their temporal variations in abundance. The microplankton communities were characterized by 14 ciliates (e.g. Strombidium sulcatum, Tintinnopsis tubulosoides and Strombidium cheshiri) and 18 microalgae (e.g. Skeletonema costatum and Alexandrium tamarense). Multiple regression analyses showed that the interspecies correlations among these dominant species represented a complex network with a clear seasonal shift. Temporal pattern of microplankton communities was significantly correlated with the environmental variables such as temperature, salinity and nitrate nitrogen. The results suggest the clear species distribution and temporal dynamics of microplankton communities in response to environmental changes, and multivariate statistical approaches were a useful tool to reveal the species distribution patterns and complex microplanktonic interspecies correlations in marine ecosystems.

Morphology and infraciliature of Holosticha bradburyae nov. spec. (Ciliophora, Hypotrichida) from the Yellow Sea, China

The living morphology and infraciliature of a new marine hypotrichous ciliate, Holosticha bradburyae nov. spec., collected from the coastal water off Qingdao (Tsingtao), China, are investigated. This species is characterized by: body size 150–320 × 25–75 μm with brownish to dark brown cell colour, ca. 53 adoral membranelles and 1 anteriorly positioned buccal cirrus; 3 frontal, 2 frontoterminal and 20–26 transverse cirri; midventral rows comprising 27-32 pairs of cirri; one conspicuous gap always present between anterior and posterior parts of AZM, and 2–5 distinctly elongated membranelles are always present at the posteriormost end; cortical granules conspicuous, round and flattened with central depression, arranged in about 10 lines on dorsal side; 28–33 irregularly arranged macronuclear nodules; 9–11 complete dorsal kineties; caudal cirri absent.

Studies on an endoparasitic ciliate Boveria labialis (Protozoa: Ciliophora) from the sea cucumber, Apostichopus japonicus

The morphology and infraciliature of an endoparasitic ciliate, Boveria labialis, isolated from respiratory trees of the sea cucumber, Apostichopus japonicus, were investigated using living observation and silver impregnation methods. Based on the present and previous studies, an improved diagnosis is supplied: marine Boveria, size in vivo about 30-100×15-30 μm, body slender and flask-shaped, with a protruding lobe measuring 5-15 μm in length; one ovoid macronucleus and one micronucleus; single contractile vacuole positioned in posterior 1/4 of body length; 17-26 somatic kinetics; paroral membrane and membranelle 2 forming a double anticlockwise spiral of nearly two turns.