The colonization features of ciliate communities have proved to be a useful tool for indicating water quality status in aquatic ecosystems. To determine an optimal water depth for bioassessment using these ecological bioindicators, the colonization process of periphytic ciliates was studied at four depths of 1, 2, 3.5 and 5 m in Chinese coastal waters. Samples were collected at time intervals of 3, 7, 10, 14, 21 and 28 days using glass slides. The periphytic ciliate communities represented similar colonization dynamics from a depth of 1 to 3.5 m: (1) the temporal variability was well fitted to the MacArthur-Wilson and logistic models; (2) the species composition reached an equilibrium during the exposure time periods of 10–14 days; and (3) the maximum abundances were definitely higher at a depth of 1 m than those at 3.5 m. PERMANOVA test revealed that the colonization pattern at 1 m depth was significantly different from those at the other three depths. Results suggest that the colonization dynamics of periphytic ciliates may be influenced by water depth in coastal waters. These findings provide an important reference for establishing an optimal sampling strategy for bioassessment on large spatial/temporal scales in marine ecosystems.

Diatoms are a primary producer and play an important role in the functioning of microbial food webs. Temporal variations in community patterns of planktonic diatom assemblages were studied during a 1-year cycle (June 2007–May 2008) in Jiaozhou Bay, northern China. Samples were collected biweekly at a depth of 1 m from five sampling stations. A total of 75 diatom species representing 40 genera, 28 family, 19 orders and three classes were recorded. Of these species, 11 distributed in all four seasons, while 27, 35, 56 and 28 forms occurred only in spring, summer, autumn and winter season, respectively. The species number and total abundance peaked in autumn, with minimum values in May. All three species biodiversity measures (Shannon diversity, Pielou's evenness and Marglef's richness) peaked in spring and autumn. There was a significant difference in diatom community patterns among seasons, except the pair of spring and winter. The environmental variables, especially temperature and the nutrients, could significantly drive the seasonal variation in diatom community patterns. Of 11 dominant species, four (Paralia sulcata, Skeletonema costatum, Guinardia delicatula and Nitzschia lorenziana) were significantly related with temperature, pH and/or nutrients. These findings suggest that the seasonal shift in community pattern of planktonic diatoms was driven by both temperature and nutrients in this eutrophic basin ecosystem.

Ciliates are a primary component of the periphyton microfauna and play a crucial role in the functioning of microbial food webs. Seasonal variation in community structures of periphytic ciliate communities was studied, using glass slides as an artificial substratum, during a 1-year cycle (August 2011–July 2012) in coastal waters of the Yellow Sea, northern China. Samples were collected monthly at a depth of 1 m from four sampling stations. A total of 144 ciliate species representing 78 genera, 43 families, 17 orders and eight classes were recorded. Among these species, 31 distributed in all four seasons, while 11, 11, 13 and two forms occurred only in spring, summer, autumn and winter season, respectively. The species number and total abundance peaked in spring and autumn, with minimum values in winter. Ciliate community structures differed significantly between seasons, and were significantly correlated with the changes in environmental variables, especially temperature, pH, dissolved oxygen (DO) and the nutrients. Of 36 dominant species (top 15 ranked contributors in each season), nine (e.g. Pseudovorticella paracratera, Trochilia minuta and Zoothamnium sp.) were significantly correlated with pH, DO or nutrients. Species richness, evenness and diversity measures were significantly correlated with temperature, pH, DO or soluble reactive phosphates. Results demonstrated that periphytic ciliates exhibited a clear seasonal variation in community structures in response to environmental conditions and potentially might be used as a robust bioindicator for assessing environmental quality status in coastal waters.

To determine potential surrogates of littoral macroinvertebrate communities for marine bioassessment and for evaluating biological conservation, the different taxonomic resolutions as surrogates were studied based on six datasets collected from intertidal zones of the Yellow Sea, near Qingdao, northern China, during the period of 1989–1998. Samples were collected yearly at five stations with different bottom types during the summer season (June). The genus- and family-level resolutions maintained sufficient information to analyse the ecological patterns of the macroinvertebrate communities for assessing ecological quality status in littoral ecosystems. The mollusc assemblages, alone or in combination with arthropod assemblages, may be used as a surrogate of littoral macroinvertebrate communities, at both species- and genus-level resolutions. The results suggest that the use of simplifications in macroinvertebrate fauna at genus-level resolutions or using smaller taxonomic assemblages (e.g. molluscs and arthropods) are time-efficient and would allow improving sampling strategies of large spatial/temporal scale bioassessment programmes and biological conservation researches in littoral ecosystems.

The diatoms are an ecologically important group of algae that have been extensively studied by ecologists and taxonomists. However, the large-scale patterns of diatom distribution and the factors underlying this distribution are largely unknown. The aims of this study were to identify the large-scale spatial patterns of benthic diatom assemblages in Korean streams and rivers, and to assess the importance of numerous environmental factors on diatom distribution. We classified 720 study sites based on diatom flora. Benthic diatoms, water chemistry, altitude, and riparian land cover and use were characterized by multivariate analyses, Monte Carlo permutation tests, and indicator species analysis. In total, we identified 531 diatom taxa. Diatom assemblages were mostly dominated by species of the genera Achnanthes, Navicula, Nitzschia, Cocconeis, Fragilaria (Synedra included), Cymbella, Gomphonema, and Melosira. Cluster analysis partitioned all 720 sites into eight groups based on diatom species composition. Canonical correspondence analysis indicated that altitude, land cover and use, current velocity, electrical conductivity, and nutrient levels explained a significant amount of the variation in the composition of assemblages of benthic diatoms. At the national scale, a downstream ecological gradient was apparent, from fast-flowing, mostly oligotrophic highland streams to slow-flowing, mostly eutrophic lowland rivers. Our data suggest that spatial factors explain some of the variation in diatom distribution. The present investigation of the spatial patterns of benthic diatoms, the ecological determinants of diatom occurrence, and the identification of diatom indicator species contributes to development of a program for assessing the biological integrity of lotic ecosystems in Korea.

Taxonomic diversity and temporal patterns in abundance of periphytic ciliate communities across taxonomic levels were studied to monitor water quality in Korean coastal waters during April 2007. Specifically we compared two methods based on an artificial substrate (glass slide): the polyurethane foam enveloped slide (PFES) and the conventional slide (CS) systems. The results demonstrated that: (1) the colonization patterns of the ciliate communities at all taxonomic levels showed a lower variability in the PFES system than those of the CS system; (2) The taxonomic diversity (Δ) and taxonomic distinctness (Δ*) were significantly higher in the PFES system than those in the CS system; and (3) all four taxonomic diversity/distinctness indices represented lower variability in the PFES system than those of the CS samples. These findings suggest that the PFES system is more effective than the CS system for measuring the colonization patterns and taxonomic distinctness parameters that are increasingly used as potential indicators of water quality. This conclusion supports our previous suggestion that the PFES system is a better tool than the CS system for monitoring water quality in the marine ecosystem, using periphytic ciliates.

Des bioessais avec l'algue Selenastrum capricornutum Printz ont été intégré en 1991 à un programme d'étude élaboré par le département Environnement de la société Elf Aquitaine Production de Boussens ; ils étaient destinés à l'évaluation en milieu d'eau douce, du potentiel eutrophisant du phosphore des lixiviats de trois boues de forage pétrolier. Le paramètre suivi est la biomasse maximale produite. Les résultats obtenus sont discutés en vue d'une évaluation et d'une correction éventuelle du potentiel d'eutrophisation des lixiviats des boues de forage. Ceci permet d'optimiser la stratégie de gestion de ces types de déblais. Les lixiviats de ceux-ci ont un potentiel eutrophisant relativement faible.