bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Altered Light and Feeding Regimes on the Zooplankton Feeding Capability of Hydra viridis
Authors: Clayton William S. 
Published: February 2007

AbstractThe effects of light regime, feeding regime and tentacle number on the zooplankton feeding capability of Hydra viridis were tested in the laboratory. Feeding was measured by exposing Hydra to a known volume of Artemia salina nauplii and recording the number captured and ingested. In all cases there was a correlation between the number of Artemia captured and the number ingested. H. viridis with 7 tentacles captured and ingested more Artemia than Hydra with 6 tentacles. However, changes in light and/or feeding regimes did not alter the number of tentacles/Hydra. Varying light and feeding regimes altered the number of Zoochlorellae/cell and Hydra growth rate. There was no effect on the number of Artemia captured or ingested and no effect on the percent ingestion of captured Artemia. These data suggest that, under these conditions, zooplankton feeding by H. viridis is independent of nutritional history.
The Filtering Rates of Four Herbivorous Crustaceans on Nannoplankton and Net Plankton Fractions in an Acid Lake in West Virginia
Authors: Janicki Anthony , Decosta John 
Published: February 2007

AbstractFour experiments were conducted in Cheat Lake, West Virginia, to determine the filtering rates of zooplankton on the size fractions of phytoplankton in an acid lake. The results showed that Bosmina longirostris filtered significantly more net plankton than nannoplankton. Results for other species were not consistent in the size fraction selected. The dominance of Peridinium inconspicuum may have made the nannoplankton fraction unavailable as food for Bosmina.
Limnology of the Kern River (Southern California)
Authors: Hill Gary , Rai Hakumat 
Published: February 2007

AbstractThe Kern River, in Southern California, was studied for twenty months. Geological and morphological effects on water chemistry were noted. Chemically, the Kern River is a Ca‐Na‐HCO3 system with an average total filterable residue of 100 mg/l. Primary production in Kern River water was limited by nitrates and, occasionally, by phosphates. Planktonic biomass was highest in February–March and Melorisira granulata was the dominant species. Chlorophyll ‐α averaged 4.17 μg/1. Radioactivity was low. Carbon forms were influenced by runoff with labile carbon being associated with the saprobic bacteria (r = +0.90). Three habitat types of flora were encountered. Total fish potential was largely restricted to man‐made Lake Isabella.
Metabolic Similarity of Palaemon Populations from Different Brackish Waters (Short Note)
Authors: von Oertzen Jörg‐Andreas 
Published: February 2007

AbstractThe oxygen consumption rates (standard metabolic level) of three Palaemon adspersus populations from Fjords in the Belt Sea (Baltic) with different salinity regimes and of Palaemon elegans from the Black Sea measured under summer temperature conditions in a flow‐through respirometer are almost identical. A possible interpretation of these findings from the evolutionary standpoint and its practical importance for research into brackish water environments is briefly discussed.
Studies on the Genus Vaucheria (Xanthophyceae) in Iraq
Authors: Islam A. K. M. Nurul 
Published: February 2007

AbstractEight species of Vaucheria from southern Iraq, V. dichotoma, V. sessilis, V. erythrospora, V. verticillata, V. hamata, V. woroniniana, V. synandra, and V. longicaulis were studied and described. All but V. sessilis and V. longicaulis are recorded for the first time from Iraq.
Scaling of Microcosms and the Dimensional Analysis of Lakes
Authors: Uhlmann Dietrich 
Published: February 2007

AbstractIn this contribution, different possibilities for designing and operating microcosms have been reviewed. Examples of geometrical and of physiological similarity between systems of different sizes and the corresponding scaling functions have been considered. The simulation of the community metabolism (% BOD removal) of waste treatment lagoons by means of microcosms and the selection of proper similarity criteria yielded results which reasonably corresponded to the data directly measured in existing full‐scale ponds and dealt with in the literature. The change in phytoplankton primary productivity per unit volume of the epilimnion with change in mean depth of a variety of lakes to be expected from dimensional analysis was found to be in good agreement with empirical data recorded in the literature.
Selenium Requirement of the Dinoflagellate Peridinopsis Borgei (Lemm)
Authors: Lindström Kåre 
Published: February 2007

AbstractAn indispensable dependence on selenium (Se) was established for the dinoflagellate Peridinopsis Borgei (Lemm.) Lemm. The alga regularly blooms in semi‐meromictic lakes close to the Baltic Sea. A vitamin B12 requirement is indicated for the alga as well as increased levels of micronutrients. A culture medium specifically designed for P. Borgei is presented.
Veränderungen im Phosphatgehalt des Wassers in einem Prielsystem im Wattengebiet nahe der Nordstrander Bucht (östliche Nordsee) im Verlauf einer Tide Changes in the Phosphate Content of Water in a Tidal Channel through the Wadden Sea near Nordstrander Bight (Eastern North Sea) during a Tidal Cycle
Authors: Lillelund Kurt , Berghahn Rüdiger , Diercking Reinhard 
Published: February 2007

AbstractThe total phosphate content of the water in a well delimited region of the Wadden Sea (26.8 km2) was determined by multiplying the concentration by the water volume during each phase of the tide. When the weather is moderate, sharp but stable gradients are observed from the shore to the open sea resulting from the remineralization processes that occur most rapidly near the shore.
Bioaccumulation and Partitioning of Cadmium within the Freshwater Mussel Dreissena polymorpha Pallas
Authors: Bias Rüdiger , Karbe Ludwig 
Published: February 2007

AbstractKinetics of uptake, partitioning and elimination of cadmium were investigated in experimental studies with the freshwater mussel, Dreissena polymorpha. The radioactive cadmium isotopes 109Cd and 115Cd were used as tracers. Shells, soft parts and body fluid of the mussel exhibited considerable differences in accumulation and elimination. Accumulation factors up to more than 70,000 were calculated for the periostracum, whereas accumulation factors for the whole mussels ranging up to 3,000 were calculated. The shells bound a great deal of cadmium, but only loosely, and the metal could be readily eliminated after transfer to uncontaminated water. In contrast, no significant amounts of the cadmium incorporated in the soft parts were eliminated. The results indicate that the major portion of cadmium in the soft parts is strongly bound and cannot be eliminated by exchange processes.
The Development of Vertical Migration Patterns in the Sediments of Estuaries as a Strategy for Algae to Resist Drift with Tidal Currents
Authors: Heckman Charles W. 
Published: February 2007

AbstractThe phenomenon of massive algae migrations to the surface of mud flats at low tide was quantitatively investigated. Differences were noted in the behavior of the individual species. This adaptation to the tidal rhythm is obviously effective for preventing the algae from drifting to the sea, and its development can shed much light on the natural history of the species involved. Euglena obtusa and Caloneis amphisbaena var. subsalina apparently arose by a natural selection process among ancestors from lentic freshwater bodies, while Navicula salinarum, Cylindrotheca signata, and several other diatoms probably invaded the freshwater habitat from marine mud flats, where they were preadapted to the tides.
Eisen und Mangan in pazifischen Tiefsee‐Rhizopoden und Beziehungen zur Manganknollen‐Genese Iron and Manganese in Pacific Deep‐sea Rhizopods and Relationships to Manganese Nodule Formation
Authors: Riemann Franz 
Published: February 2007

AbstractThe Pacific deep‐sea bottoms are dominated by rhizopodan Protozoa. Their abundance on manganese nodules and in the associated sediments suggests a contribution to nodule formation, though direct evidence is still lacking. Attention is called to iron contents in solid excretion products of some sessile rhizopods that may contribute to the initiation of manganese deposition and nodule growth. Manganese is scarce in the faecal pellets of sediment‐dwelling rhizopods. This is discussed in context with questions regarding manganese mobilization in pelagic sediments.
Ecological Study of Freshwater Zooplankton of a Subtropical Pond (Karnataka State, India)
Authors: Patil C. S. , Gouder B. Y. M. 
Published: February 2007

AbstractFortnightly records of the biotic and abiotic conditions in a subtropical natural pond were made over a period of 14 months with a view to find out the abiotic causes of fluctuations in the zooplanktonic populations. Statistical analysis of simple correlations among the abiotic factors revealed direct relationships between water temperature, DO and pH and an inverse relationship between DO and ‐PO4 at statistically significant levels (P<0.01). The relationships between the physical and chemical factors and the zooplanktonic groups were evaluated by partial and multiple correlation coefficients. The causes for variation in the populations were established by stepwise multiple regression analysis. The populations of copepods and rotifers, respectively, were correlated at the 5 % and 1 % levels of significance to conductivity and ‐PO4 which might be indirectly affected by bicarbonates and phytoplankton growth. The occurrence of two peaks of zooplankton, one in winter and another in postsummer, were observed to follow the Microcystis aeruginosa bloom.
Some Physical and Chemical Properties of Water from an Undisturbed Tropical Catchment Area (Guma Dam, Sierra Leone)
Authors: Mtada Obed S. M. 
Published: February 2007

AbstractThe water had a very low content of total suspended solids (<1 mg l−1), but its transparency was high (5–8 Hazen units). The concentration of Mg++ and Ca++ were below 1 mg l−1, but that of SiO2 was 5.3 mg l−1. Free CO2 was abundant (15.3 mg l−1) and the pH was low (<6.5). These conditions were accompanied by low concentrations of PO4‐P, total iron and NO3‐N. The DO content of the water was always below 80 %, but the chloride concentration (8.4 mg l−1) seems relatively high for this type of freshwaters. It is, however, much lower than that known for arid areas. It is concluded that the geology and vegetation dominate the chemistry of the water from the Guma Dam catchment area. The influence of man is acknowledged only in as far as he has protected the catchment area.
Recording the Motor Activity of Aquatic Animals by Ultrasound
Authors: Rosenfeld Eike , Millner Rudolph , Grosse Wolf‐Rödiger , Schuh Joseph 
Published: February 2007

AbstractAn ultrasonic technique based on the Doppler effect is presented to allow the registration of aquatic animal movements. The method was tested on crucians (Carassius carassius) in an aquarium as part of chronobiological investigations. Comparison with light barrier measurements shows that the Doppler technique is suitable for detecting typical circadian and seasonal changes in the motor activity of the fishes. The features of the ultrasonic method are discussed.
Marine Benthos in Relation to Pore Water Chemistry and Sediment Geochemistry of Simulated Dredged Material
Authors: Maurer Don , Church Thomas M. , Wethe Charistian , Lord Charles 
Published: February 2007

AbstractDuring the course of study on vertical migration and mortality of benthos in simulated dredged material, changes in pore water chemistry and sediment geochemistry were also examined. Dissolved oxygen, ammonia, and sulfide showed significant changes between overlying water and pore water over the two week experimental period. Chemical effects in dredging operations can be important on infaunal organisms.
Primary Production and Effects of Enrichment with Nitrate and Phosphate on Phytoplankton in the Barra Bonita Reservoir (State of São Paulo, Brazil)
Authors: Henry Raoul , Hino Kozo , Gentil José Geraldo , Tundisi José Galazia 
Published: February 2007

AbstractPrimary productivity of the phytoplankton was evaluated by the 14C and dissolved oxygen methods in December 1981 at the Barra Bonita Reservoir (São Paulo State, Brazil). The primary production varied between 0.17 to 14.51 mg C m−3h−1 at 4 and 0 m depth, respectively. About 57 to 94% of the photosynthetic activity was due to phytoplankton > 50 μm. The highest value of assimilation rate (3.36 mg C mg Chl−1h−1) was found in the surface water. Dissolved nutrient concentrations were very high and consisted mainly of nitrate. Light penetration was low, the aphotic zone accounting for about 90% of the water column. Enrichment with nitrate and phosphate showed that both N and P stimulated the production of biomass (chlorophyll a), mainly due to the addition of phosphate. The enrichment experiment also indicated that phosphate addition has a significant stimulatory effect on the growth of Melosira sp. The limiting effect of light penetration on photosynthetic activity is more severe than that of nutrients.
Investigations into the Food Selectivity of the Planktic Crustaceans Daphnia hyalina, Eudiaptomus gracilis and Cyclops vicinus
Authors: Horn Wolfgang 
Published: February 2007

AbstractThe food selectivity of Daphnia hyalina, Eudiaptomus gracilis and Cyclops vicinus was investigated in laboratory experiments using algae of different sizes and at different concentrations as food sources. Vanderploeg and Scavia's (1979a, b) coefficient, which is most suitable for characterising selectivity, was selected from the literature and used to analyze the results. None of the three species was found to feed selectivity, however. The results show, on the other hand, that the leaky‐sieve model can be used to describe the feeding patterns of these species. There were clear differences between the particle size ranges consumed by our experimental species, and these showed that, during the experiments, Daphnia hyalina acted as a microfilter‐feeder, whereas Eudiaptomus gracilis and Cyclops vicinus acted as macrofilter‐feeders.
Methods of Modelling the Age Dependent Ration Changes of Plankton Crustaceans Feeding on Variable Quality Food
Authors: Gruzov Lev N. 
Published: February 2007

AbstractMethods of formalizing trophic interactions within plankton communities are discussed on the basis of correlations observed between prey size and specific and age‐dependent features of the consumer. The nature of the functional reaction of copepods to changes in food quality is specific to the different age groups. Allometric types of relation between food ration and body size cannot describe these phenomena. An alternative method based on the notions of minimum, maximum and optimum prey size changing in the course of ontogeny is suggested. The values of the parameters are identified for the species of Temoridae and Acartiidae (Copepoda, Calanoida), and a range of examples proves satisfactory reproducibility of the experimental data concerning mono‐ and polyphagy. This paper presents a biological interpretation of the parameters that suggest their functional connection with mesh size, mouth size and the ability of copepods to dismember large objects into portions. Optimum food size is expressed as a function of age and size of modal class particles that enabled “switching” of food as a result of changes in the component ratio in the environment and different capturing capabilities to be modelled. Some conclusions resulting from the model are discussed.
The Benthic Macrofauna Associated with the Oyster Reefs of the James River Estuary, Virginia, U.S.A.
Authors: Larsen Peter F. 
Published: February 2007

AbstractProductive, natural oyster reefs within the James River estuary, were quantitatively sampled for associated macrofauna for a year. The 192 samples yielded 142 taxa. Mean faunal density on these reefs ranged from 5,757 to 57,857 m−2. Over 770/0 of the individuals collected belonged to 11 taxa. The number of species and informational diversity (H') decreased up the estuarine gradient.The quality of available shell surface was deemed important in determining density. The spatial heterogeneity provided by the shell surface allowed development of a densely populated, diverse faunal assemblage which differs from soft‐bottom assemblages principally in quantitative aspects. The assemblage is not spatially or temporally homogeneous and undergoes significant changes in community structure both seasonally and along the estuarine gradient.
An Examination of Cell Volume in Dominant Phytoplankton Species of the Central and Southern Adriatic Sea
Authors: Viličić Damir 
Published: February 2007

AbstractThe phytoplankton biomass expressed as total cell volume is often of doubtful value due to cell size and volume variations in the organisms present. Cell volume calculations for 95 phytoplankton species and volume‐frequency diagrams for 25 dominant species were analyzed for the Adriatic Sea. Recommendations for more precise work dealing with phytoplankton cell volume and biomass are given. Temporal variations in the average microplankton cell volume are presented and discussed.
Limnological Observations on Rihand Reservoir (Uttar Pradesh) with Reference to the Physical and Chemical Parameters of its Water
Authors: Singh R. K. 
Published: February 2007

AbstractObservations in respect of Rihand Reservoir based on monsoon inflow, reservoir level, evaporation loss, air and water temperature, rainfall and wind velocity have been discussed in relation to the physical and chemical parameters of the water body. A weak thermocline has been observed, and the water showed a biogenic chemical stratification during the warmer months. Rihand is a monomictic tropical lake with a moderate nutrient supply, but is not very productive from the limnological point of view. The nutrient content of this lake declined from 1972 to 1974, but improved in 1975 and 1976 with the increase in rain and inflow of water. The productivity of the reservoir depends greatly on the nutrient level of the inflowing water from the catchment area, so that the monsoon inflow largely influences the water quality of the reservoir.
Desmids of Iraq
Authors: Nurul Islam A. K. M. , Yousuf Haroon A. K. 
Published: February 2007

AbstractForty species and varieties of desmids belonging to the genera Closterium (7), Pleurotaenium (1), Euastrum (3), Cosmarium (28) and Staurastrum (1) have been described from southern Iraq including two new varieties under Cosmarium (i.e. C. cyclicum Lund, var. mesopotamianum var. nov., and C. tyrolicum (Nordst.) Krieger & Gerloff var. minor var. nov.). Most of the taxa are new records for Iraq.
Seasonal and Spatial Distribution of Iron Precipitating Heterotrophs in Water and Sediments of Fish Ponds of Differing Farming Managements
Authors: Jana B. B. , Patel G. N. 
Published: February 2007

AbstractPopulation densities of primarily iron precipitating heterotrophs (metal‐precipitating non oxidizing bacteria) were estimated in water and sediments of ponds being used for polyculture, monoculture and traditional systems of fish farming over a period of two and a half years. Spatial differences in microbial density in the ponds were related to the organic loading of the farm site and the type of farming. The highest bacterial populations occurred in November and the lowest in summer. Nitrite concentration was mainly responsible for such seasonal changes.
Effects of Oil Refinery Effluents on Selenastrum capricornutum PRINTZ
Authors: Gaur J. P. , Kumar H. D. 
Published: February 2007

AbstractLaboratory‐based bioassay experiments using Selenastrum capricornutum PRINTZ as the test organism were conducted to evaluate the potentiality of refinery effluents to sustain algal growth. The raw effluents were remarkably toxic to the test alga, but satisfactory algal growth occurred in (diluted) 0.01 % effluents. The effluents from subsequent treatment stages required much less dilution to eliminate the toxicity. This study implicates oil and phenol in the reduction of algal growth in refinery effluents. A highly significant negative correlation was found between the final yield of the test alga and the concentration of oil or phenol in the culture suspension. The bioassay experiments therefore point to the toxic nature of refinery effluents. On the basis of these findings it is recommended that proper dilution of refinery effluents is necessary before they are discharged into any body of water.
Morphological Form Variation in a Loricate Rotifer, Keratella tropica APSTEIN from a Perennial Pond, Janaktal, Gwalior, India
Authors: Saksena D. N. , Sharma S. P. 
Published: February 2007

AbstractMorphological form variation in a loricate rotifer, Keratella tropica APSTEIN is decribed. Form variation in this rotifer involves appearance and development of the left postero‐lateral spine. The right postero‐lateral spine varies, too. It increases with increasing length of lorica and left postero‐lateral spine. Three morphological forms, viz. reducta, asymmetrica and heterospina are recognized.
Role of Unionidae and Sphaeriidae (Mollusca, Bivalvia) in the Eutrophic Lake Zbęchy and its Outflow
Authors: Kasprzak Krzysztof 
Published: February 2007

AbstractThe abundance, biomass, respiration, and filtration rate of the Unionidae and Sphaeriidae and their significance to the phosphorus cycle was estimated in an eutrophic lake in Poland, situated in an agricultural area, and in its outflow canal. A decrease in Unionidae biomass was compensated for the Sphaeriidae in terms of both biomass and filtration rate. Depending on the developmental state of the Unionidae and Sphaeriidae populations, the volume of pumped water, the amount of removed and assimilated seston and the phosphorus excretion changed significantly.
Deposition and Decomposition of Turtlegrass Leaves
Authors: Newell Steven Y. , Fell Jack W. , Miller Christine 
Published: February 2007

AbstractIn coastal zones where prevailing winds are onshore, seagrasses are regularly deposited at the shoreline, often forming large accumulations. We have compared the rates of output of dry matter, organic carbon, and nitrogen for turtlegrass (Thalassia testudinum) when it decays at the shoreline or continuously submerged nearby. Output rates were either delayed (by 30 days or more) or were significantly slower for decay under submerged conditions.
Interactions of Physical, Chemical and Biological Processes in Depth and Time within a Productive English Lake during Summer Stratification
Authors: Heaney S. I. , Smyly W. J. P. , Talling J. F. 
Published: February 2007

AbstractA survey is given of physical, chemical and biological events in the water‐mass of a productive lake (Esthwaite Water, N. England) during summer stratification. They are interrelated in terms of i) responses to meteorological changes (ii) susceptibility to density stratification (iii) participation in acid‐base and redox systems, with interactions of these (iv) modification due to the generation of particulate material from soluble precursors (v) limiting factors in such bio‐generation (vi) mechanisms of internal nutrient loading, and (vii) control by the characteristics of individual plankters. The significance is demonstrated of differential inputs of meteorological variables, and especially of biological production and degradation, for determining the overall structure and metabolism of the lake.