bluuebunny/crossref_metadata_2025_split huggingface dataset:
Die Trichoptera‐Emergenz im Mittellauf eines Bergbaches des Thüringer Waldes (Insecta, Trichoptera)
Authors: Mey Wolfram 
Published: February 2007

AbstractFifty‐seven species of caddisflies were identified in samples taken over a 7‐month period from a large emergence trap placed on the mid‐reach of a forested mountain stream in the Thuringian Forest, East Germany, in 1984. A total of 4,673 specimens were obtained during the sampling period. The community was dominated by collectors and shredders (52 % and 35.6 % of biomass) indicating a high input of allochthonous organic material from the bank trees as well as from upper stretches of the stream. The emergence periods and patterns of the common species are described and compared. Some species showed significant departures from a balanced sex‐ratio. An explanation is proposed to account for the general unpredictability of sex‐ratios in emergence traps. Unusual emergence patterns of 5 species are discussed in detail.
Species Composition and Habitat Preference of Watermolds in the Nainital District of Kumaun Himalaya, India
Authors: Mer G. S. 
Published: February 2007

AbstractA total of thirty two species of watermolds have been identified from the entire study area. Of these, 22 % species were restricted to water, 44 % to soil and 34 % occurred in water and soil both. The maximum number of species were found during rainy season in both the ecosystems. Pythium s pp. were dominant in terrestrial ecosystem whereas Pythium s pp. and Saprolegnia spp. were dominant in water system. There were two clusters indicative of presence of two distinct communities in both the systems.
The Structure of Molar Surfaces of the Mandibles of Sidoidea (Crustacea: Daphniiformes). 1. Holopediurn gibberum ZADDACH, 1848
Authors: Glagolev Sergey M. , Korovchinsky Nikolay M. 
Published: February 2007

AbstractThe morphology of mandibles of Holopedium gibberum was studied using scanning electron microscopy. They are strongly asymmetric and differ with that of Anemia and Podonidae and similar with that of Branchinecta and Daphniiformes especially Penilia.
Deep‐sea Environmental Disturbance and Recovery Potential
Authors: Thiel Hjalmar 
Published: February 2007

AbstractMining the abyssal seafloor for manganese nodules will destroy the hard substrate and it will severely disturb the seabed and the benthic soft substrate community. Recolonization will occur from unmined areas. Reestablishment of a community similar to that originally present is, however, not possible, since the nodules will be removed and epigrowth on hard substrates is thereby precluded. Small scale experiments using azoic sediment in trays exposed to ambient deep‐sea conditions, may not be appropriate models for large scale recolonization processes.Results of such experiments and general knowledge of deep‐sea ecology suggest that decades may be required for reestablishment of a balanced community.With respect to evaluation of some ecological consequences of mining an ongoing large scale experiment, termed DISCOL (DIS‐turbance and re‐COL‐onization) is shortly described as a new approach in deep‐sea risk assessment.
Hydrobiological Studies on Suraj Kund and Chandrama Kund, Hot Springs of Rajgir, Bihar, India
Authors: Jha Mahendra 
Published: February 2007

AbstractThe hot water of Rajgir springs is used for drinking and bathing purposes by tourists. Certain physico‐chemical characteristics (temperature, pH, NO, PO, etc.) of the water along with phycological parameters viz. community composition, species diversity, standing crop etc. were measured from June 1986 to April 1987. The water was deficient in Na, NO and PO ions. The hot springs were mainly dominated by algae belonging to Cyanophyceae and Bacillariophyceae. The algal community comprised 18 species, with dominance of Cyanophyceae over Bacillariophyceae. While Mastigocladus laminosus and species of Phormidium were dominant in Suraj Kund, species of Oscillaroria and Synechococcus dominated in Chandrama Kund. Diatoms comprised about 10 % of the algal community. Though there was a considerable seasonal change in species diversity of the algal community the total biomass (chlorophyll a extracted per unit area from the algal mat) remained constant.
Considerations on Representative Water Quality Data
Authors: Håkanson Lars 
Published: February 2007

AbstractThe aim of this paper is to give a brief summary concerning important methodological aspects in establishing the reliability of empirical water quality data. These considerations are relevant for applied work e.g. monitoring programmes, as well as theoretical research, e.g. to validate models. The paper concerns data from Swedish lakes on Hg in pike, perch, water and sediments, and a broad set of limnological data (pH, Secchi depth, temperature, alkalinity, total‐P, conductivity, Fe, Ca, hardness, chlorophyll‐a and colour). These standard parameters generally vary in a lake, both temporally and areally. The focus of this paper is on such variations and how to express lake‐typical values. There are large differences in analytical reliability for different parametres; e.g. Hg (in fish and sediments but not in water) and lake pH can generally be determined with a comparatively great accuracy; the average relative standard deviation (V) is only about 2‐3% for pH. Colour, Fe‐, total‐P‐concentration and alkalinity, on the other hand, generally give high V‐values. In natural lakes, the variability is often at least twice as large as the “methodological” variability for parameters such as colour, P, Fe and alkalinity (V‐values ranging between 20 and 40% on average in our lakes). This implies that for most parameters one must analyse many samples to obtain representative, lake‐typical values with a given statistical reliability. A general furmula expressing how many samples are required to establish lake‐typical mean values is discussed as well as statistical aspects concerning the range of empirical data in models based on such data.
Nutrient Interactions and Phytoplankton Growth during the Spring Bloom Period in Lake Erken, Sweden
Authors: Eriksson Cecilia , Forsberg Curt 
Published: February 2007

AbstractFactorial enrichment experiments with nitrate‐N, phosphate‐P and selenite‐Se, were conducted in situ, with natural phytoplankton assemblages, during two consecutive spring‐bloom periods (1983 and 1984) in Lake Erken, Sweden. Nutrient conditions, biomass indicators and algal physiological status, in experiments and in lake water, were compared. Characteristic peaks of phytoplankton, dominated by diatoms, developed in the lake in both years. In 1984, chlorophyll a biomass (30 μgl−1) reached almost twice that of 1983 (17 μgl−1). Inorganic P resources were depleted in both years, but inorganic N was exhausted only in 1984. In 1983, Stephanodiscus hantzschii GRUN v. pusillus GRUN. KRIEGER completely dominated the biomass peak. In 1984, Melosira islandica v. helvetica O. MÜLL occurred in great numbers along with S. hantzschii v. pusillus. The growth rate of S. hantzschii v. pusillus, surplus phosphorus dynamics and potential alkaline phosphatase activity were different during the two spring periods. In the experiments, eight alternative nutrient situations were tested during four phases of the natural phytoplankton development. The algae responded to enrichments during the entire phytoplankton bloom in 1983 and 1984. Nutrient interactions were important, especially in 1983, and occurred most frequently during the late exponential phase, biomass maximum and declining phase in both years. Interactions between N and P were most common in 1983, occurring during the late exponential phase and biomass maximum. N and Se interaction occurred occasionally. Interactions between P and Se were more frequent in 1983 than in 1984. When nutrients interacted, the combined effect was generally smaller than the sum of their individual effects. P deficiency indicators and the experiments showed clearly that the bloom of 1983 was P limited. In 1984 no such clear pattern was found.
Effets du retard dans la première alimentation sur le développement de la larve planctotrophe de l'oursin Paracentrotus lividus
Authors: Fenaux Lucienne , de Greef Yves , Cellario Christiane 
Published: February 2007

AbstractThe growth of the skleleton and changes in biochemical constituents (proteins, carbohydrates and lipids) were observed in embryos (days 0 and 1) and larvae (2‐8 days) of the sea urchin Paracentrotus lividus that were starved (C 0) or fed low (1,000 cells of Hymenomonas elongata, C 1) or high (5,000 cells, C 5). Different batches of C 1 and C 5 larvae were fed first the 2nd, 3rd, 4th or 5th day after fertilization. Initiation of feeding 24 h after hatching slowed down the rate of increase in length of the larval appendages. A differential growth of skeletic rods (somatic and postoral rods) and variations in proteins weights shows the existence of a mixotrophic phase between endotrophic and planktotrophic phases. Best development occured in larvae which were first fed at the lower food level 24 h after hatching.On the 2nd and the 3rd day the somatic/postoral rod ratio is ≥1. This higher ration can be used to estimate the age of natural populations of larvae.
Sedimentary Losses in the Reservoir Saidenbach: Flux and Sinking Velocities of Dominant Phytoplankton Species
Authors: Horn Heidemarie , Horn Wolfgang 
Published: February 2007

AbstractSedimentation of phytoplankton was studied in the meso/eutrophic reservoir Saidenbach for two years and measured as biovolume in a sedimentation trap near the bottom. It comes to an annual average of 2.76cm3/m2 × d (0.4… 10.9) and is statistically significant dependent on the free water concentration measured 14 days before. This allows flux to be reliably calculated without any direct measurement. The bottom is reached above all by diatoms which form 90% of the deposited algae. The sinking velocity of the diatoms is mainly determined by their physiological state: During growth phases low sinking velocities (0.1 … 2m/d) were found, while in decline phases they increased considerably (>6m/d). The highest average sinking velocities found among large diatoms were calculated for Fragilaria crotonensis (3…4m/d), the lowest for Melosira italica (1.5…2m/d). The values for Asterionella formosa, Synedra acus and Diatoma elongatum were between them. Turbulence has no influence on sinking velocity (usually, spring full circulation sees the highest sedimentary losses), but plays an essential part in the survival of the population in free water. Permanent redistribution prevents diatoms from sinking out from the euphotic layer, this “inoculation” making further development possible. On an annual average, phytoplankton forms approximately only one quarter of the whole trap sediment (max. 62%). The flux of the dry weight of seston (2.33g/m2 x d on an average) reflects the changes in phytoplankton flux negligibly only and does not reveal any relation to it. so that seston flux is not suitable for determining phytoplankton sedimentation. But it is possible to calculate this at a probability of 65 to 94%, by using the free water concentration measured 14 days before.
Macrozoobenthic Assemblages of the Evros Delta (North Aegean Sea)
Authors: Gouvis N. , Koukouras A. 
Published: February 2007

AbstractThe composition of the macrozoobenthic assemblages of the Evros Delta (North Aegean Sea) has been investigated by means of 4 replicate quantitative samples, collected at 35 sites. The information obtained from the numerical analysis of the faunal samples and the analysis of other data (values of the main physico‐chemical parameters) revealed the presence of a single community. The faunal composition of this community varies locally according mainly to the salinity and secondly to the particle size of the substrate. The community is described on the basis of its biological parameters and compared with corresponding assemblages from other areas.
Influence du Régime Alimentaire sur la Composition Chimique Elémentaire de Nebalia bipes (Crustacea, Leptostraca)
Authors: Kerambrun P. , Guerin J.‐P. 
Published: February 2007

Effect of Diet on the Elementary Chemical Composition of Nebalia bipes (Crustacea, Leptostraca)Changes in carbon, hydrogen and nitrogen contents of Nebalia bipes were studied under different artificial feeding conditions. Using a multifactor ANOVA, highly significant variations were observed according to diet. C:N ratio, which was 4.99 ± 0.31 in control animals, exhibited extreme values of 3.96 ± 0.09 and 5.52 ± 0.49. From a trophic point of view, the results demonstrate the large possibilities of N. bipes to exploit very different resources. The variability of its elementary chemical composition expressed in C:N ratio is compared to other generalist species.
Calcite Precipitation in Hard Water Lakes in Calculation and Experiment
Authors: Proft G. , Stutter E. 
Published: February 2007

AbstractCalcite precipitation in model solutions and natural waters depends on the magnitude of saturation (saturation index ≫ 1). Continuous lye addition should simulate the CO2 decrease through assimilation by algae and the experiments can be applied to the autochthonic calcite precipitation in lakes. It seems possible to restore lakes with artificial calcite precipitation. Basic data for this experiment are given in this paper.
Sublittoral Protistan Communities of the Shores of the Sea of Cantabria (Bay of Biscay)
Authors: Fernandez‐Leborans Gregorio , Novillo Apolonia 
Published: February 2007

AbstractThe composition of the protist communities of three coastal areas of the Sea of Cantabria were studied, and the seasonal variation of the larger groups of these organisms described, with respect to the productivity. Also, the annual dynamics of consumption and degradation of organic matter achieved by the ciliate species were analyzed.
The Biogeography of Tropical Phytoplankton Species in the Pacific Ocean
Authors: Semina Halina J. , Levashova Sophia S. 
Published: February 2007

AbstractThe ranges of 10 tropical Pacific phytoplankton species are shown in the maps. Five types of these ranges are discussed. Except for broadly tropical species some species with much narrower ranges are characterized. The bases of ranges and the expatriation areas are given. The bases of ranges of all the species studied fall into similar temperature and salinity limits. Most of the species inhabit a wide range of nutrients concentration, but Climacodium frauenfeldianum and Hemiaulus hauckii are only found at low phosphate and silicate concentrations. These peculiarities determine the geography of ranges of these two species. Among the species investigated only Ceratium gravidum belongs to the shade flora.
Distribution and Species Composition of Zooplankton in Himalayan Ecosystems
Authors: Raina H. S. , Vass K. K. 
Published: February 2007

AbstractThe zooplankton communities of lakes, Sars, wetlands and ponds in Jammu‐Kashmir Himalayas were examined. The waters are situated between 600–3800 m a. s. l. and, in the ordinates 30°–36° N. Significant variations in Rotifers and Crustacean distribution patterns were encountered. Some species having wide tolerance limits are more frequent while a few species due to their rigid environmental demands are restricted to few water bodies. Such species serve as good indicators of trophic evolution. The general distribution of these groups and their ecological implication have been discussed in the paper.
Phytoplankton — Community Structure, Succession and Chlorophyll Content in Lake Müggelsee from 1979 to 1990
Authors: Nixdorf Brigitte , Hoeg Sigrid 
Published: February 2007

AbstractOne aspect of the present work on Lake Müggelsee has been a quantitative assessment of phytoplankton changes over the annual cycle and from year to year as a basis for primary production measurements. The investigations of plankton analysis were carried out in Lake Müggelsee (Großer Müggelsee, Berlin), a eutrophic, polymictic shallow lake with an area of 7.2 km2, a mean depth of 4.9 m. The lake was described as a species rich water with partially considerable developments of diatoms and blue‐green algae as was shown by plankton analyses from the beginning of this century. Since the end of the 60s, when macrophytes disappeared, Lake Müggelsee has been recognized as a lake with extensive phytoplankton development characterized by dense and irregular development of blue green algae and diatoms. Especially solitary centric diatoms increased in number and in biovolume from 1979 to 1990 and occurred with greater diameters in spring during the seasonal course.The specific content of chlorophyll a was estimated according to the algal composition. It is suggested that the observed decrease in Chl a per unit biovolume is associated with species size rather than the time of development depending on the unknown portion of inactive algal cells resuspended from the sediment surface.
Long‐term Annual and Seasonal Changes of Meta‐ and Protozooplankton in Lake Müggelsee (Berlin): Effects of Eutrophication, Grazing Activities, and the Impact of Predation
Authors: Arndt Hartmut , Krocker Maria , Nixdorf Brigitte , Köhler Antje 
Published: February 2007

AbstractAnnual changes of rotifers, copepods, cladocerans, the ciliate Epistylis rotans, and larvae of Dreissena polymorpha were analysed for the period 1908–1990. Though food resources increased 6–10 fold in the course of eutrophication, only rotifers and Epistylis increased accordingly. Probably as a result of increased predation pressure crustaceans increased only twice.The seasonal pattern of metazoans and protozoans (flagellates, sarcodines, ciliates) were analysed for 12 and 3 years, resp. During winter and spring, large heterotrophic flagellates and ciliates dominated the zooplankton and were responsible for a pronounced ‐ formerly underestimated ‐ grazing pressure on phytoplankton. In early summer, metazoan filter‐feeders were often able to cause a significant reduction of phyto‐ and protozooplankton. However, during some years, phytoplankton declined in the absence of a pronounced grazing pressure. Field data and experiments revealed that predators were able to regulate the density of cladocerans in early summer (mainly cyclopoids) and summer (mainly Leptodora, smelt and fish juveniles).
Seasonal Changes in the Plankton Dynamics of a Eutrophic Lake Including the Microbial Web
Authors: Nixdorf Brigitte , Arndt Hartmut 
Published: February 2007

AbstractDuring 1989 and 1990 the carbon dynamics in the shallow eutrophic Lake Müggelsee (Berlin) were investigated by analysing the seasonal succession of phytoplankton, metazooplankton, protozooplankton and bacteria. Size fractionated algal primary production and exudation were measured as well as bacterial production in order to calculate the amount of carbon covering the bacterial carbon demand by primary production. The impact of bacterivorous protozoans and metazoans was estimated by comparison of the calculated feeding rate and the bacterial production. Our results show a shift within the metabolic interactions of the microbial food web from winter/spring to summer, indicating a high significance of the protozooplankton as a regulator on bacteria during the colder season, whereas from early summer the influence of metazooplankton dominated by cladocerans was evident in this eutrophic lake.
Lake Oxygenation: Application of a One‐box Model with Ice Cover
Authors: Livingstone David M. 
Published: February 2007

AbstractA one‐box exponential model with constant coefficients is capable of giving a good description of the winter oxygen uptake of a lake not subject to freezing over. A simple modification of the model accounts well for the effects of ice cover. The modified model predicts that, all else being equal, the oxygen regimes of eutrophic lakes will tend to be affected more by ice cover than those of oligotrophic lakes; that a short period of ice cover is of no great consequence for the oxygen regime of the lake, whereas a long period of ice cover results in a disproportionately large decrease in the mean lake oxygen concentration; and that the later break‐up occurs, the greater will be the effect of the ice cover on the oxygen regime of the lake.
Changes in the Benthic Macroinvertebrate Community in Two Years of Colonization of New Experimental Ponds
Authors: Christman Van D. , Voshell J. Reese 
Published: February 2007

AbstractThe objective of this study was to determine if the benthic macroinvertebrate community structure in a set of experimental ponds changed significantly during the second year of their existence. This is an important factor in pesticide registration testing using this type of facility. One year has been established as sufficient time to develop a complete community but this has never been tested. Comparison of the community at the end of year 1 to the community at the end of year 2 showed no significant differences for community summary measures (total density, taxa richness, diversity, Bray‐Curtis similarity index); however, some individual taxa densities were significantly lower at the end of year 2. Physicochemical parameters measured indicated that the ponds were oligotrophic. Submerged macrophytes colonized and became established in most of the ponds during year 2. With the exception of a few noninsect taxa, the experimental pond communities appeared similar to mature communities in shallow lentic environments. Additionally, the seasonal changes observed in the pond communities followed expected patterns.
Tube‐dwelling Meiofauna in Marine Sediments
Authors: Nehring Stefan 
Published: February 2007

AbstractTube‐dwelling has been recognized previously as a life‐style for several meiobenthic species, but behavioural observation of living specimens has rarely been reported. The extent to which tube‐building and tube‐dwelling occurs within meiofauna, and how they have influenced evolutionary and ecological processes as well as morphology within these organisms, is relatively unknown but potentially of great significance. In addition to direct observation of tube‐building and the occurence of tubes in natural habitats, the internal anatomy associated with tube‐building in two nematode species (Ptycholaimellus jacobi, P. ponticus) and one harpacticoid copepod species (Stenhelia palustris) is the focus of this study. Special attention is given to the secretory products, glands, and their association with secretory pores. Also, the role of meiobenthic tube‐dwelling activities in relationship to their environment is extensive discussed.
Participation of a Specific Substrate Degrading Strain in a Mixed Bacteria Culture as a Result of Ciliate Grazing
Authors: Macek Miroslav , Hartmann Petr , Škopová Ivana 
Published: February 2007

AbstractParticipation of nitrilotriacetic acid degrading bacterial strain NTA‐1 in the continuous‐cultivated mixed culture was studied under different conditions including predation pressure of the ciliate Dexiostoma campyla (STOKES, 1886). From the viewpoint of dispersed/flocculated biomass distribution, significant relationships between NTA‐1 and total bacteria ratio, and dispersed and total biomass ratio were proved in the systems without high concentrations of ciliates. The ciliate concentrations reaching 104 ml−1 stabilized flocculated biomass growth without directly affecting NTA‐1 portion. Using fluorescently labelled NTA‐1 bacteria, filter feeding rates of ciliates were evaluated (maximum individual uptake rate upon NTA‐1 bacteria as a number of bacteria per ciliate per hour being 120 h−1 and 260 h−1 under ciliate division rate of 0.3 day−1 and 1 day−1, respectively). Biomass balance showed that dispersed NTA‐1 bacteria should not serve as the sole feeding source for these free‐swimming ciliates. The role of diversity of mixed bacterial diet in ciliate growth and the role of ciliate predation in stabilizing bacterial assemblage structure was proved.