bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experiments on Nitrogen and Phosphorus Release by Chironomus ex gr. plumosus from the Sediments of Lake Balaton, Hungary
Authors: Tátrai István 
Published: February 2007

AbstractSediment‐water systems of Lake Balaton mud and tap water were constructed in plexiglass tubes and boxes for evaluation of changes in the nitrogen and phosphorus contents of overlying water as influenced by chironomid density and light conditions.Nitrogen flux from sediment was greatly influenced by denitrification process. The amount of TN released by chironomids amounted to about half of the yearly nitrogen fixation rate in Lake Balaton.Omnivorous chironomids increased the phosphorus content of the overlying water. The rate of release was density dependent. TP release rates ranged between 1–17 mg m−2 day −1 over a range of densities 500–20,000 larvae m−2.It became evident that aerobic sediment cores can be an important nutrient source in lakes where chironomids inhabit them at densities above 1,000 larvae m−2.
Enzymatic Evaluation of Oxidation Pond Performance
Authors: Hosetti B. B. , Patil H. S. 
Published: February 2007

AbstractA one year study on a waste oxidation pond was undertaken to observe the behaviour of four enzymes, viz catalase, phosphatase, protease and amylase with respect to other ecological factors. The increase in solar radiation from March to May enhanced phytoplankton growth resulting in increased pH and DO and considerable reduction in nutrients and BOD. Variations in the activity of enzymes seemed to be directly related to bacterial number. The activity of catalase and phosphatase seemed to be related to the microbial density and nutrient status of the pond. The activity of protease and amylase could be used as a measure of degradation of organic matter.
A Remark on Microorganisms in Lake Sediments with Emphasis on Polyphosphate‐accumulating Bacteria
Authors: Uhlmann Dietrich , Bauer Hans‐Dietrich 
Published: February 2007

AbstractBacteria which are able to store large amounts of phosphorus as polyphosphate (PP) under aerobic conditions and to release it under anaerobic conditions are utilized for the advanced treatment of sewage. This note presents some results which indicate that PP‐accumulating bacteria which possibly participate in the immobilization and release of dissolved phosphate may also be present in lake sediments.
Comparison of the Benthic Size Structure Between Sublittoral, Upper‐slope and Deep‐Sea Areas of the Western Pacific
Authors: Shirayama Yoshihisa , Horikoshi Masuoki 
Published: February 2007

AbstractBenthic size structures were compared between sublittoral, upper‐slope and deep‐sea areas of the Western Pacific using the mesh‐size fractionated distribution of organisms. The average size of the individuals became smaller with increasing water depth, suggesting that the dwarfism is a more common phenomenon than the gigantism in the deep sea. Nonetheless, the mesh size of 0.037 mm was fine enough to retain meiobenthic specimens quantitatively. When the whole benthos was divided into macro‐ and meiofauna, the size distributions overlapped considerably in a mesh‐size fraction between 1.0 and 0.5 mm. In this fraction, the meiofauna predominated over macrofauna in the deep sea, while the opposite applied to the shallower depths. From these results, recommended mesh sizes of the sieves for the studies of macro‐ and meiobenthos were proposed.
Herbivores and the Spatial Distributions of the Phytoplankton. I. The Plankton Market
Authors: Wirick Creighton D. 
Published: February 2007

AbstractPlanktonic herbivores forage on phytoplankton cells which were produced at some earlier time and at a distant place. A steady state, one dimension model of the birth, death and eddy diffusion of phytoplankton illustrates phytoplankton smooth both temporal and spatial variations as they are transported. When the eddy diffusivity is k and the phytoplankton doubling time is b, the average distance traveled by a phytoplankton cell is (kb)1/2 and the average time spent doing so is b. Only those spatial variations with wavelengths greater than 2π(kb)1/2 and temporal variations with periods greater than 2πb will be observed in the phytoplankton distributions at more than half their original amplitude. Both k and b control the length scale of phytoplankton distributions in a cartesian coordinate system. Planktonic herbivores view the phytoplankton from a diffusing coordinate system in which the spatial scales of the phytoplankton distribution are transformed into time scales.
Variation of Phytoplankton in a Tropical Estuary (Vellar Estuary, Bay of Bengal, India)
Authors: Krishnamurthy K. , Mani P. , Krishnamurthy K. 
Published: February 2007

AbstractThe phytoplankton species composition and community structure were studied at two stations in the Vellar estuary from January to December, 1983. A total of 117 species of phytoplankton belonging to various groups, namely diatoms (90), dinoflagellates (21), Chlorophyceae (3), Cyanophyceae (2) and silicoflagellates (1) were observed during the study. The species diversity, richness and evenness values varied from 0.7 to 4.2 units/individual, 0.9 to 5.7 and 0.19 to 0.75 respectively. Dominance index values varied between 32.6 and 96.4 during the study period.
ATP as an Index of Phytoplankton Productivity. The Chl a/ATP Quotient
Authors: Nωges Tiina 
Published: February 2007

AbstractThe seasonal changes in the adenosine triphosphate (ATP) and chlorophyll a (Chi a) concentrations in two eutrophic lakes (Lake Peipus, Lake Vōrtsjärv; Estonia) were studied in the course of two years. Comparative measurements were performed in the Baltic Sea. The main task was to examine how the ATP content of the water characterizes the functional state of the phytoplankton community. Primary production, total phosphorus and total nitrogen were measured as supplementary parameters. The under‐ice bloom in Lake Vōrtsjärv was also observed. The under‐ice bloom, consisting mainly of the diatom Melosira islandica spp. helvetica, started at the bottom of the water body and spread over the whole water column in a few days. The ATP content correlated well with changes in the chl a concentration of the bottom water, but in the uppermost regions of the water column no correlation was found. Obviously most of the cells had died before reaching the surface layers. Seasonal observations showed an accumulation of “dead” chlorophyll in autumn. The Chi a/ATP ratio increased in the following order: sea—eutrophic lake—hypereutrophic lake. The values of the index increased exponentially as the phytoplankton standing stock increased.
Perch, Perca fluviatilis L., in Small Lakes: Relations between Population Characteristics and Lake Acidity
Authors: Rask Martti 
Published: February 2007

AbstractPerch population characteristics of small lakes were examined with a special reference to lakes which have acidified recently due to atmospheric deposition of air pollutants.The population density and biomass of perch were higher in an acid (pH 4.5) clear water lake with low aluminium concentration than in recently acidified (pH 4.3–4.7) clear water lakes with higher aluminium levels. The structure of perch population in an acid (pH 4.4) humic lake was similar to recently acidified clear water lakes.The population density and the biomass of perch were significantly higher in 6 lakes with pH>5.0 than in 6 lakes of pH<5.0 whereas the mean age and length at a given age were higher in the more acid lakes.
Amphipoda (Crustacea) in the Littoral Zone of Lake Balaton (Hungary). Qualitative and Quantitative Studies
Authors: Muskó Ilona B. 
Published: February 2007

AbstractSpecies composition, size distribution, egg number and biomass of different amphipod species on littoral submerged aquatic vegetation (Myriophyllum, spicatum and Potamogeton perfoliatus stands) and on the stony shores of Lake Balaton at Tihany were estimated in August 1983 and 1985. Three species occurred in the material: Corophium curvispinum, Dikerogammarus haemobaphes and Dikerogammarus villosus. The bulk was formed by C. curvispinum. The mean number of eggs per female of the three investigated species showed differences at the different sampling stations and ranged between the following values: C. curvispinum from 3.3 to 8.8, D. haemobaphes from 16.4 to 22.8 and D. villosus from 8.0 to 17.5. The total biomass of amphipods was 1.8 and 3.5 mg dry weight/g fresh weight of macrophytes in 1983 and 1985 respectively, and 4.7 mg animal per dm2 stone surface in the stony littoral zone in 1983.
Daphnia and Toxic Blooms of Microcystis aeruginosa in Bautzen Reservoir (GDR)
Authors: Benndorf Jürgen , Henning Manfred 
Published: February 2007

AbstractAs a part of a whole‐lake, long‐term experiment in biomanipulation in. the hypertrophic Bautzen reservoir (G.D.R.), during three years (1984–1986) the dynamics of mouse‐related LD 50 of Microcystis aeruginosa was compared with the biomass development of this blue‐green and the grazing pressure exerted by Daphnia galeata. Since the three summer averages of the biomass of D. galeata revealed strong differences due to decreasing predation activity of fish from 1984 to 1986, the effects of different grazing pressure on Microcystis toxicity could be investigated under field conditions. Microcystis was nontoxic at the beginning of the growing season and developed high toxicity during its first strong biomass increase in summer in all three years. But this decrease of the LD 50 together with the first biomass increase of the season is found in quite different periods in different years (1984: August, 1985: July, 1986: June). It is obvious that the higher the mean effective filtration rate of D. galeata during summer is found the faster the toxicity of Microcystis is formed. If these observations are combined with findings of other authors, the conclusion can be drawn that the development of toxic Microcystis blooms seems to be promoted by a combination of five conditions:(1) Presence of a mixture of toxic and nontoxic Microcystis strains at the beginning of the growing season even if the portion of toxic strains is very low, (2) physical and chemical growth conditions which favour Microcystis over other phytoplankton, (3) high grazing pressure by zooplankton on edible food particles over a rather long period, (4) patchy distribution of the different Microcystis strains if nonselective filtrators such as Daphnia dominate the zooplankton, and (5) absence of defense mechanisms of Microcystis against grazing which are not coupled with toxicity (e.g. large colony size). These conclusions contribute to a better understanding of the possibilities and limits of in‐lake eutrophication control by biomanipulation and emphasize the need to combine top‐down and bottom‐up control mechanisms in eutrophic and hypertrophic waters.
The Effect of pH on Copper Toxicity to Blue‐Green Algae
Authors: Lüderitz V. , Nicklisch A. 
Published: February 2007

AbstractThe effect of pH on copper toxicity to two planktonic blue‐green algae, Aphanizomenon gracile and Oscillatoria redekei, was investigated. Growth rates of the algae without copper treatment decrease with pH, Aphanizomenon is earlier and more affected than Oscillatoria. On the other hand, pH‐lowering leads sooner to a toxicity enhancement in Oscillatoria. In the acid range, toxicity retardation occurs in Aphanizomenon. At pH 5.1, shortening of the interval between copper toxicity and copper stimulus is characteristic for both species.
Some Observations on the Irradiance and Carbon Fixation in Grane Langsø
Authors: Nygaard G. 
Published: February 2007

AbstractPhotosynthetically active radiation (PAR) was registered daily in 0.25 m and 11.25 m in 3 years. Upwards irradiance of green light was 1 % of downward irradiance. Incubator 14C experiments showed that the phytoplankton enhanced its carbon uptake substantially with increasing concentrations of the carrier CO2 in the ampoules. Severe carbon limitation of photosynthesis occurred in spring and summer 1961, where the real carbon fixation was only about 34 % of that calculated by the usual procedure. Utilization of light and DIC by the phytoplankton and its compensation depth was determined. Photoinhibition occurred down to 10–11 m, and net primary production was nearly always positive in any depth down to the lake bottom.
Field and Laboratory Studies on Nile Phytoplankton in Egypt III. Some Physical and Chemical Characteristics of Aswan High Dam Lake (Lake Nasser)
Authors: Ahmed Ahmed M. , Mohammed Ahmed A. , Springuel  , El‐Otify Ahmed M. 
Published: February 2007

AbstractSeasonal, local and monthly vertical variations in physical and chemical characteristics of Aswan High Dam Lake (AHDL) were followed during the period from March 1982 to February 1984. The results show that there were distinct seasonal thermal variations. Similarly, thermal stratification was evident from late spring through early autumn. Oxygen content appeared to vary with the changes in pH value. Water transparency in the southern part was greatly reduced by the incoming silt laden flood especially in summer months. Consequently, nitrate‐nitrogen and total residue increased considerably in this part during summer. The recorded minimum N‐concentration (2.35μg l−1) was certainly limiting the growth of phytoplankton. Suspended and organic matter exhibited somewhat irregular variations at least during the period of this study.
Field and Laboratory Studies on Some Photosynthetic Bacteria in Aswan High Dam Lake I. Some Physical and Chemical Characteristics
Authors: Shoreit A. A. M. , Ahmed A. M. , Shabeb M. S. A. 
Published: February 2007

AbstractSeasonal variations in some physical and chemical characteristics of samples collected from summer 1984 to spring 1985 and vertically from the surface to the bottom at two sites along the main body of Aswan High Dam Lake and in two side Khors were studied. Water temperature showed seasonal as well as vertical variations. The pH values were in the vicinity of 8.0. Dissolved oxygen concentrations were higher at the surface than at the bottom. The total dissolved solids showed seasonal as well as irregular vertical variations. Bicarbonates, nitrates, and silicates showed a marked increase with depth, while sodium, potassium, calcium and magnesium showed generally a slight or, sometimes, marked increase with depth. Phosphates and sulfates showed a slight or marked decrease with depth. Chlorophyll a decreased with depth while bacteriochlorophyll a increased.
A Mathematical Model for 137Cs Uptake and Release by Filamentous Algae
Authors: Švadlenková Marie , Dvořák Zdenêk , Slávik Ondrej 
Published: February 2007

AbstractA mathematical model of the dynamics of radiocaesium transport in the aquatic phase—algae system is suggested in this work. Allowance is made for algae growth and for both reversible and irreversible absorption of this radionuclide by the algae. The algae biomass is divided hypothetically into two compartments with different exchange kinetics. The parameters of the model are time dependent. The model is quantified using experimental data for the concentrations of 137Cs in Cladophora glomerata filamentous algae and in water, obtained in situ in the environment of a nuclear power station. The model fits the data reasonably well and can be applied, for example, in bioindication of radioactivity in aquatic recipients in the environment of nuclear power stations.
Reproduction and Larval Ecology of the Blue Swimming Crab Portunus pelagicus in Ragay Gulf, Philippines
Authors: Ingles Jose A. , Bkaum Erich 
Published: February 2007

AbstractThe Ragay Gulf situated at the southeastern part of Luzon is an important fishing area especially for the blue crabs. Commercial landings are caught by traps, gillnets and trawls. Most prevalent catching method is by means of baited traps called “Bubo” in Pilipino. Landings fluctuate yearly and were 641 t in 1984 and 210 t in 1985. The hydrographic situation especially the current system changes seasonally with existing monsoon periods. Females of the blue swimming crab in the Gulf reach maturity at a mean carapace width of 10.5 cm. In tank experiments they spawned 13 days after copulation. Though berried females were found throughout the whole year, two main spawning periods exist namely, one from February to April and another from July to October. Larvae hatched 5 to 6 days after oviposition at 29.5 °C and 4 zoea stages were observed. The horizontal and vertical distribution as well as the possible transport mechanism of zoeae are discussed in relation to the existing current systems and the orientation behaviour of the larvae. Because of the very few megalopa samples caught in this study, its distribution pattern has only preliminary character.
Collembola in the Bed Sediments of an Alpine Gravel Stream (RITRODAT‐Lunz Study Area, Austria)
Authors: Bketschko G. , Christian E. 
Published: February 2007

AbstractIn the creek “Oberer Seebach”, 355 springtails belonging to 42 species were collected from the water‐filled pore space of the bed gravel proper and the adjacent bank sediment. Almost 10 % of 2094 samples contained Collembola, with a mean density of 1.8 specimens per positive sample. The topographic distribution of the most abundant species Lepidocyrtus lignorum, Agrenia bidenticulata, and Folsomia quadrioculata suggests that riparian and eurytopic forms are frequently washed into the channel and transported down to a considerable sediment depth without injury to the animals. The rising groundwater table in the bank sediment traps no riparian, but predominantly hemiedaphic species. Euedaphic springtails are rare, especially in the groundwater samples.
Fish Community Structure on a Deep Ocean Outfall, Barber's Point, Oahu, Hawaii
Authors: Russo Anthony R. 
Published: February 2007

AbstractThe Barber's Point, Oahu, Hawaii sewer outfall structure attracts large numbers of fish (500 — 1000 per 336 m2 bottom area) and fish species (23—29) not normally seen over flat, soft bottoms characteristic of the diffuser (66 m) isobath. Except for fish species strictly associated with corals, the adult fish community parameters (species richness, abundance, and composition) were similar to shallower natural Hawaiian reef environments. The adult fish species composition at the diffuser changed significantly during the discharge of heavy flocculated pre‐treated sewage (15 mgd). High rates (15 mgd) of pre‐treated sewage may cause decreases in total fish abundance and species richness when compared with the discharge of primary effluent with little or no flocculation between 0 and 19 mgd. Two fish species, which were generally abundant in Hawaiian waters during the years of observation, were absent at the outfall during discharge of heavy flocculated pre‐treated effluent.
Ecology of Some Ricefields in Japan as Exemplified by Some Benthic Fauna, with Notes on Management
Authors: Kurihara Yasushi 
Published: February 2007

AbstractThe role of tubificids and mud snails in the ricefield ecosystem was elucidated using their ecology as a basis for highlighting problems in the strategy of recycling between agricultural and urban activities.Tubificid oligochaetes occur in high densities in ricefields where irrigation water is polluted with sewage, high organic matter content is present in the soil and when highly toxic insecticides are not used. High tubificid densities reduce and even eliminate weeds, change the composition and density of bacteria and increase the density of zooplankton. Also they serve as a high quality source of food for fish comparable to that of insects. Conditions that promote a healthy growth of tubificids obviate or reduce the need for weedicides and high levels of inorganic fertilizers.Mud snails which thrive in ricefields have been used as an important source of protein food for humans in rural Japan. The snails can consume a sludge‐reed compost mixture used as a fertilizer in ricefields. However the high heavy metal content in the sludge is accumulated by the snails which are thus unfit for human consumption. Based on these results and the known ecology of tubificids and the snails, a possible recycling system comprising sewage sludge, reeds, fish, insects and egrets using these two kinds of benthic organisms is proposed.
Live Algae in Deep Sediment Layers
Authors: Wasmund Norbert 
Published: February 2007

AbstractExamination of sediment cores taken from shallow coastal regions of the Baltic showed that some algae were still alive at depths beyond the depth of light penetration. Their cells contained chlorophyll and photosynthesis resumed when they were exposed to light. Photosynthesis was detected by simultaneous measurement of oxygen production and 14C uptake. Autoradiography was used to detect incorporated 14C. The autoradiographic method was improved by a few modifications.
Response of Phytoplankton to Copper Treatment with Reference to Species Sensitivity
Authors: Lüderitz Volker , Nicklisch Andreas 
Published: February 2007

AbstractResponses of different planktonic algae species to copper treatment were tested using semi‐continuous culture and compared with studies on copper‐induced changes in species composition of phytoplankton samples. Blue‐green algae exhibit lowerEC100‐values than diatoms andScenedesmus.The four tested strains ofMicrocystis aeruginosashowed different copper sensitivity.Four response types can be distinguished.1. rapid biomass loss after copper application but subsequent growth recovery.2. fluctuations of growth but no loss of biomass at sublethal concentrations3. continuous recovery of growth rates after initially affected growth.4. growth inhibition (dormancy) and recovery after inoculation into a copper‐free medium.Species response to copper application within a phytoplankton sample agrees with pure culture behaviour.
Sediment Chemistry of Lake Bhim Tal, U. P., India
Authors: Gupta P. K. , Pant M. C. 
Published: February 2007

AbstractCertain chemical constituents (NO3‐N, bio‐available P, Ca, Na, K, Mn, Cu, Co and organic matter) together with pH, Eh and clay content of surface sediments at various depths of the overlying water in Lake Bhim Tal were examined during 1977—1978. In addition, NH3‐N and dissolved oxygen at the mud‐water interface (water immediately above the sediments) were measured.The values of Eh, pH and NO3‐N in the sediments showed a negative relationship with water depth and positive relationship with dissolved oxygen at the interface. The other variables of the sediment were positively related to water depth and negatively related to dissolved oxygen at the interface. Organic matter, K, Na and Ca showed positive relationship with the amount of clay while the cations (K, Na, Ca) and trace metals (Cu, Mn, Co) showed a positive relationship with the amount of organic matter in the sediments.
Toxicity of Piperonyl Butoxide — Carbaryl Synergism on the Snail Lymnaea acuminata
Authors: Singh D. K. , Agarwal R. A. 
Published: February 2007

AbstractEffects of piperonyl butoxide and carbaryl synergism were studied on the metabolism of the snail Lymnaea acuminata. Snails were exposed to 40 % and 80 % of the 48 h LC50 of carbaryl or carbaryl + piperonyl butoxide mixture (1:5). The amount of carbaryl present in the LC50 mixture was only 0.23 % of the LC50 of carbaryl alone. The treatments caused a dose‐dependent decrease in glycogen and protein levels and acetylcholinesterase (AChE) and alkaline phosphatase activity; simultaneously, there was an increase in levels of lactic acid, reducing sugars and amino acid and the activity of acid phosphatase. Significant differences in AChE and phosphatase activity were also observed between the effects of equivalent concentrations of carbaryl and carbaryl‐synergist.