Zooplankton community changes between forest and meadow sections in small headwater streams, NW Poland

Headwater streams are important resources in production of organic matter, but zooplankton of headwater streams has rarely been studied. In the present study spatial changes in zooplankton communities between upper headwater forest section and downstream meadow section of four small streams were examined (NW Poland). The environmental conditions of stream riparian zone, e.g., the presence of leaf litter, pools, slackwaters and wetlands had a great influence on the spatial changes in zooplankton. Low gradient of stream bed, longer water residence time and larger surfaces of wetlands and slackwaters also positively affected zooplankton communities, especially in the meadow section. Along the streams, from the stream headwater to the downstream-meadow section, significant spatial changes in zooplankton communities were observed. Significantly higher number of taxa and density of zooplankton were observed in meadow sections than in headwater forest sections. In the forest sections, there was a definite domination of benthic and littoral rotifers in the zooplankton composition, while in the meadow sections, planktonic rotifers dominated. Cladocerans were observed only in downstream meadow section; two littoral species Coronatella rectangula and Peracantha truncata and one planktonic Daphnia magna which probably were washed from close pools of small stagnant water bodies. Copepods were noted along the entire length of streams. The occasional presence of planktonic rotifers in the forest section was probably caused by their washout from a few small stagnant water bodies.     

Zooplankton feeding on seston in the Rhone River plume area (NW Mediterranean Sea) in May 1988

In the Rhone delta area the seston concentration was maximum in the plume waters where small-sized particles dominated, while marine waters were characterized by large particles. The food conditions were optimal for grazers in the interface layer, where the high chlorophyll concentration contrasted with the low values found under the plume.The mesozooplankton specific composition did not show marked difference in and outside the plume. No special pattern for particle size selection by grazers appeared in the plume, contrary to marine waters, where largest particles were the most intensively grazed. The calculations of specific ingestion and filtration rates show that the plume waters (particularly at the salinity interface) were more favourable to zooplankton feeding than the marine ones (outside and under the plume). Nevertheless, taking into account the high level of seston biomass in the whole area studied, the daily grazing pressure of mesozooplankton was very low.     

Zooplankton communities in the Southern Weddell Sea (Antartica)

Summary Standardized abundances of 40 frequently occurring macrozooplankton taxa collected by double-oblique bongo net hauls between the surface and 200 m depth were submitted to an agglomerative hierarchical cluster analysis, to characterize surface zooplankton communities in the southern and eastern Weddell Sea. The sensitivity of the analysis concerning reduction of the number of considered taxa (especially stages of species) was tested. Dominant taxa in the entire area over the whole period were copepods Metridia gerlachei and Calanoides acutus. Calanus propinquus, Appendicularia spp. and calyptopis-1 larvae of krill, Euphausia superba were abundant at 73°S/19°W. Euphausia crystallorophias and larval fish Pleuragramma antarcticum dominated at 77°S/40°W on the southern shelf. The cluster analysis revealed marked similarities between the southern shelf community and the January community further to the northeast. E. crystallorophias, and larval Pleuragramma antarcticum are thought to be transported in surface layers of the coastal current to the southwest. Oceanic species such as Thysanoessa sp. and E. superba are probably not transported in the same way. Possible mechanisms for the maintenance of the community structures are discussed. A simplified method of characterizing communities, based on analysis of euphausiids, is presented.     

Phytoplankton community structure in non-stratified lakes of Pomerania (NW Poland)

Hydrobiologia - The species composition, abundance and biomass of autotrophic picoplankton and larger phytoplanktonic organisms were analysed in 17 non-stratified lakes of Pomerania. Water samples...     

Distribution and production of Chironomidae (Diptera) in the lower course of the Grabia River (Central Poland)

SUMMARY.

• 1 A fifth-order section of the Grabia River was investigated over two years: 1984/85 (low water level) and 1985/86 (high spate). Chironomidae (thirty-nine species) dominated the macrobenthos in both years.
• 2 In 1984/85 (mean annual water temperature 10.2°C), the number of Chironomidae species in coarse sediment was highest in spring (thirty-three species) while in sand it was highest in summer (fifteen species). A decrease in species richness was recorded in autumn and winter at each of the established sites. The estimated Chironomidae production for the whole river section was 5.37 g dry wt m^?2 yr^?1, but it differed widely amongst the study sites, ranging from 3.75 to 12.07 g m^?2 yr^?l.
• 3 In 1984/85 (mean annual temperature 8.1°C) there occurred a summer spate which was more intense than any recorded over the previous 20 years. This substantially reduced the number of species, the greatest reduction being in the coarse sediment, which was buried with sand during the spate. Production for the whole section decreased to 1.17 g m^?2 yr^?1, and the variability amongst sites ranged from 1.04 to 1.45 g m^?2 yr^?1.

     

Diversity measurements in shrubland communities of Galicia (NW Spain)

Diversity was studied in 10 communities, including the understory of native oak woodland, planted woodlands (pine and eucalypt), and shrublands in the strict sense (heathlands, broom shrublands, gorse shrublands).In each community, species richness, diversity, dominance and evenness were analysed. Differences were observed among communities with regard to species composition, richness in annual herbs, perennial herbs and shrubs, dominant plant families (Ericaceae, Papilionaceae) and diversification of shrub species.The possible relations between environmental stress and/or human influences on differences in diversity are discussed.     

Benthic communities on a sandy Ligurian beach (NW Mediterranean)

The different components of the benthic community of a sandy microtidal beach (Arenzano) in Liguria (NW Mediterranean) were investigated during late spring (May) 2002 and 2003. Sampling was carried out in two transects, chosen in order to represent the characteristics of the entire beach and their eventual spatial variations. Each transect included two stations: one placed in the swash zone (SW) and one in the surf zone (SF). Although no significant differences were found in the sediment texture over the 2 years (t-tests p > 0.1 for all the granulometric fractions), notwithstanding an increase in the mean grain size (from 0.8 to 1.1 mm) between the sampling periods, 2002 was characterised by a higher quantity of organic matter (on average 14.4 vs. 3.6 gC m⁻² for the sum of proteins, carbohydrates and lipids) and higher bacterial biomass (on average 1.9 vs. 0.9 gC m⁻²). The metazoan assemblages (meiofauna and macrofauna) were also richer (density = 2.9 × 10⁵ vs. 1.0 × 10⁵ ind. m⁻², biomass = 0.09 vs. 0.03 gC m⁻² for meiofauna; density = 1988 vs. 739 ind. m⁻², biomass = 0.14 vs. 0.03 gC m⁻² for macrofauna) in 2002. A significant quantitative reduction (t-test for proteins, carbohydrates and lipids, at least p = 0.004) in the food supply in 2003 affected the abundance of the metazoans, as confirmed by a multivariate analysis that clearly differentiated the 2 years, and seemed to inhibit their relationships within the benthic food web. The bacterial biomass was always dominant, even under the least favourable trophic conditions, due to the ability of bacteria to adapt to a very harsh environment. Our results suggest that the food supply played an important role in the benthic community structures of the beach during late spring, bacteria being the key organisms within the benthic system. The communities seemed to be bottom-up controlled, while predation seemed to be irrelevant.     

Zooplankton in a Danube River Arm near Rusovce (Slovakia)

Poor quantity of zooplankton was recorded in a Danube arm situated on the right side of the Danube River in Slovakia (river km 1857) in 2002 and 2003. All over the year the arm is significantly influenced by groundwater by reason of seepage. Because of low mean water temperature (12°C) and poorly developed macrovegetation in particular, the arm reminds gravel pit-like. The annual average of zooplankton biomass was low and ranged from 0.35 g m⁻³ (2002) to 1.28 g m⁻³ (2003), because of low crustacean abundance. Total cladoceran abundance was excessively low in both years and ranged from 3.5 N L⁻¹ (2002) to 16.6 N L⁻¹ (2003). Small species, Bosmina longirostris and Chydorus sphaericus were dominant. Only four adult Copepoda — Cyclops vicinus, Thermocyclops crassus, Eurytemora velox and Eudiaptomus gracilis — were recorded in quantitative samples of both years. In the zooplankton assemblage dominated rotifers (Synchaeta pectinata, Synchaeta oblonga, Polyarthra dolichoptera and Keratella cochlearis) which represented 78% and 67% of total abundance respectively. The total of 19 species of rotifers, 34 Cladocera species and 16 taxa of Copepoda were found.     

Dynamics of Anguillicola crassus larval infections in a paratenic host,the ruffe (Gymnocephalus cernuus) from the Oder River on the border of Germany and Poland

The course of infection of 2-year-old ruffe (Gymnocephalus cernuus L.) from the Oder River (Germany/Poland) with third-stage larvae (L3) of Anguillicola crassus (Nematoda: Anguillicolidae) was investigated at monthly intervals between March 1994 and March 1995. Of 230 fish examined, 152 (66%) harboured viable L3. Monthly prevalences fluctuated between 12 and 96%; mean intensities ranged from 1.0 to 5.6 L3 per infected fish. Temperature-dependent differences in infection were noted with the prevalence and mean intensity of infection being significantly higher (Chi-Square test and Mann-Whitney-U-test, respectively; ) at water temperatures less than 10 degrees C (cold period) than at those above (warm period). These differences remained significant even after the division of fish samples into two size classes (8.5-10.5 cm, 11-13 cm). Although the paratenic hosts may acquire infections year round, the results suggest that ruffe become infected mainly during the cold season and that the host's feeding ecology determines the final course of infection.     

Zooplankton versus phyto- and bacterioplankton in the Maltanski Reservoir (Poland) during an extensive biomanipulation experiment

Qualitative and quantitative analyses of plankton were carriedout during biomanipulation studies conducted in 1993–1996in the Malta     

The diversity and longitudinal changes of zooplankton in the lower course of a large, regulated European river (the lower Vistula River, Poland)

The diversity and longitudinal variation of zooplankton in the lower Vistula River were analyzed. Samples were taken from 40 stations located along a 272-km long section of the lower river course. During the study the unique technique of taking samples from “the same water” was used. The zooplankton community was dominated by rotifers and nauplii — larval stages of copepods. The most abundant species were: Brachionus angularis, Brachionus calyciflorus and Brachionus budapestiensis. The zooplankton species diversity in the main channel of the lower Vistula River was similar to other large European rivers; however, its abundance was lower. The diversity, abundance and biomass of potamoplankton steadily decreased downstream. This could be related both to scarcity of storage zones for potamoplankton development in the river due to the extensive regulation processes, and changes in hydrological conditions of the main channel (by the straightening of riverbed) where the samples were collected.     

Organic matter in the River Krutynia (Masurian Lakeland,Poland)

The chemical composition of drift in the lake-river system of the Krutynia River was investigated in May and August of 1987–1989. The main chemical component of drift was organic carbon, four fractions of which were distinguished: dissolved (DOC), fine particulate (FPOC), coarse (COPC) and large particulate organic carbon (LPOC). The most important of these was DOC, representing 88–100% of the TOC transported. Among the POC, the finest fraction (FPOC) prevailed, constituting as much as 98.3% of dry weight of the particulate matter. There were no significant differences between the average content of CPOC and LPOC, although significant seasonal changes were observed. Concentrations of both dissolved and particulate forms of carbon decreased with distance downriver, but that of POC diminished faster, possibly because of the effect of the lake.     

Paramecium aurelia species complex in the River Raba (southern Poland)

This report reveals a significant acidity of the River Raba at all the investigated sampling points, and rather poor differentiation of the zooplanktonic organisms. At one sampling point the presence of Paramecium biaurelia was registered.     

北京白河与温榆河浮游动物调查

2004～2006年对北京地区白河和温榆河浮游生物群落进行调查.结果显示:白河浮游动物137种,隶属于78个属,其中原生动物最多,共计73种,其次是轮虫55种,枝角类7种,桡足类2种;温榆河浮游动物135种,隶属于83个属,其中原生动物共计65种,轮虫类53种,枝角类13种,桡足类4种.两河浮游动物种类组成大部分相同,以原生动物为主,但两河大型浮游动物的种类组成差别较大.据两条河流浮游动物的生态状况和凋查结果综合分析,白河的水质较好,多数站点水体清洁,只有少数站点水体达轻度污染,温榆河水质较差,大多数站点水体属轻度污染,个别站点属中度污染.     

新安江（新溪口段）浮游动物调查报告

本文通过对新安江（新溪口段）浮游动物组成的定性和定量研究,鉴定出浮游动物２８属４３种;初步探讨了该江段浮游动物的季节变化规律,并评价了水质营养状况。     

Zooplankton dynamic of Lake Prespa (Macedonia)

The composition and temporal abundance patterns of zooplankton community in Lake Prespa pelagic zone were studied throughout an annual cycle (October 2008–September 2009). Eighteen species (10 Rotifera, 5 Cladocera, 2 Copepoda, 1 Mollusca) were evidenced. It includes Arctodiaptomus steindachneri, an endemic calanoid of the Western Balkans. The zooplankton density varied during the investigated period and certain seasonal successions in temporal transpositions of their maximal development were noticed. The total zooplankton density was much higher in spring and summer period. The representatives of subclass Copepoda were dominant during the whole year. The dominant species was A. steindachneri. At the second place (with exception of the winter period) were the Cladocera representatives. The dominant species was Daphnia cucullata. At the third and fourth place were rotifers and larval form of Dreissena polymorpha, respectively. The quantitative presence of the Copepoda representatives was significantly lower in terms of the previous investigations. The Cladocera quantity reached high values during this period, particularly in summer. Such altering in the quantitative ratio between Copepoda and Cladocera in favor of the Cladocera, especially high quantitative presence of D. cucullata, typical for eutrophic lakes, imply of significant changes in zooplankton community and changes of the water quality in Lake Prespa pelagial.     

Seasonal variation in composition and production of planktonic communities in the lower River Rhine

1. The composition and activity of phytoplankton, zooplankton and bacterioplankton in the lower River Rhine were measured in 1990 as part of an international biological inventory of the river. A seasonal study was carried out on two stations: one in the river mouth (km 1019) and one at the German/Dutch border (km 863). 2. High densities of phytoplankton (with up to 140 μg chlorophyll a 1-^?1) and occasional depletion of dissolved silicate were observed at the upstream station. Phosphate concentrations were also lowered during blooms. 3. Phytoplankton blooms, dominated by a few species of centric diatoms, declined one order of magnitude during downstream transport. During non-bloom conditions (low) algal densities were maintained during transport, or increased slightly, indicating the suitability of the river reach for algal growth. 4. Bacterial cell number and production (measured by the ³H-thymidine method) showed a broad summer maximum with activity peaks (0.5 nK < M thymidine h^?1) coincident with declining phytoplankton blooms. Winter values of bacterial production (0.02–0.05 n < Mh^?1) were substantial, probably as a result of allochthonous input of organic matter. 5. Rotifers and crustaceans made up the greater part of the zooplankton biovolume, but at the upstream station the contribution of Dreissena larvae and rhizopods was also substantial. High zooplankton biovolumes, of over 500 × 10⁶μm³1-^?1, were observed only during the phytoplankton spring bloom. 6. Quantitative relationships between the high phytoplankton production (2.1–3.4 gCm^?2 day^?1), the high bacterial substrate uptake (0.5–1gCm^?2 day^?1), and grazing were analysed for the growing season 1990. Algal grazing by metazoan herbivores was substantial only during spring, while the role of phagotrophic microplankton and cell lysis were indicated as major factors responsible for the downstream decline of phytoplankton blooms in the lower Rhine.     

Algal communities of the Hadera River (Israel) under dramatic niche changes

The Hadera River is the most polluted among the Mediterranean coastal rivers of Israel due to abundant E. coli, high concentrations of heavy metals and nutrients, and high temperatures. In 2003–2008 we found 191 species of algae and cyanobacteria belonging to seven taxonomic divisions. The upper reaches were dominated by cyanobacteria and exhibited levels of toxic pollution. Downstream, the ecological niches of algal communities dramatically changed: upper stream diversity first increased and then decreased due to the influx of rainwater in the tidal zone during winter. On one hand, seasonal dynamics show that in winter, inorganic contamination was reduced because of dilution by the influx of rainwater, but, on the other hand, organic pollution increased from agriculture. Down the river, diversity increases and the community composition undergoes considerable change. In summer, algal blooms indicate a reduction of stress and aid in the river’s self-purification. The WESI indices and RPI show steady year-round stressful conditions for algal photosynthesis with increasing instability in the river. Perpetuation of the current situation would disturb the self-purification capacity of the river ecosystem through destruction of biotic components. Statistical analysis (CCA) reveals the impact of wastewater as the most important stress factor for the Hadera River ecosystem, which is an exceptionally strong example of self-purification.     

Response of macroinvertebrate communities to anthropogenic pressures in Tajan River (Iran)

The Tajan River was investigated for one year in seven stations, analyzing the relationships between physical properties, water chemistry and aquatic macroinvertebrates. Biotic and diversity indices were compared with canonical unconstrained (CA) and constrained (CCA) ordination to test different methods able to estimate river ecology status. An upstream-downstream gradient was emphasized, in presence of anthropogenic stressors, coming from trout farms, paper factory, agriculture, urbanization, river regulation; the first CCA axis emphasized a natural gradient, bound to altitude, source distance, water temperature, the second CCA axis a pollution gradient. Biotic and diversity indices detected three polluted stations: S3, downstream the Korcha tributary, S6 downstream a paper factory and S7 situated after the Sari town. S4 showed high macroinvertebrates densities, which were attributed to the presence of a dam. Both multimetric and multivariate methods emphasized the need to separate the influence of natural variables from anthropogenic stressors in the Tajan River. To separate the influence of longitudinal gradient from the influence of pollution, it was suggested to evaluate the anthropogenic impact as deviation from a regression line, considering a multimetric index as dependent variable and source distance as predictor variable. The definition of reference sites was problematic in this poorly investigated area and a progress in taxonomic resolution is in any case recommended to better define the ecological status of these waters.