bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulations in a Plankton Model
Authors: Hendrickson William H. , Reddy Karri S. B. , Shar Albert O. 
Published: February 2007

AbstractA technique for analyzing the stability of a zooplankton, phytoplankton, nutrient interaction model is described. This is an extension of a two‐dimensional predator‐prey model, incorporating a nutrient food source. In this study difference equations, rather than differential equations, are used to simulate the system since the systems are more easily studied in this formulation. Using only a few reasonable constraints on the system, a remarkable stability is obtained.
An Analysis of the Biotic Community in a Kumaun Himalayan Lake, Nainital (U. P.), India
Authors: Pant M. C. , Sharma A. P. , Sharma P. C. , Gupta P. K. 
Published: February 2007

AbstractA comprehensive study of phyto‐ and zooplankton and macrozoobenthic components in Lake Nainital showed that species richness was high for plankton and low for macrozoobenthos. The algal biomass was dominated by greens (54 %) and blue‐greens (31 %), the zooplankton population by copepods (84 %), and the macrozoobenthic community by a Tubifex‐Chironomus association constituting≥95 % of the annual number of the macrobenthic invertebrates. Respiration (807.5g C m−2 year−1) surpassed gross production (630.5 g C m−2 year−1). The mean annual ratio between phyto‐ and zooplankton biomass is 3.3 and between phytoplankton and herbivores it is 4.6. If biomass is treated as a measure of crude production, the relationship among the three trophic levels suggests that herbivory is inefficient while carnivory is efficient, because part of the primary production remains unutilized by dominant herbivorous zooplankters, whereas Mesocyclops leuckarti, the sole carnivore, feeds efficiently on rotifers and juveniles of other copepods. The low diversity of different biotic components and the P/R ratio of less than 1 perhaps suggest that the lake is passing through the stage of heterotrophic succession.
Chemical and Microbiological Processes as Regulators of the Exchange of Substances between Sediments and Water in Shallow Eutrophic Lakes
Authors: Ryding Sven‐Olof 
Published: February 2007

AbstractIt is generally believed that excessive P release from lake sediments, i. e. internal P load, is only a problem in deep lakes with stagnant anaerobic bottom waters. However, substantial amounts of P can also be released from sediments in shallow, well‐mixed lakes. The dynamics and magnitude of P release from sediments in these types of lakes are affected primarily by physical factors, such as seasonal variations in water temperature and year‐to‐year differences in water renewal. These factors, in turn, induce chemical and microbiological processes which regulate the exchange of substances between sediments and water. The fractional distribution of sedimentary P and the chelating capacity of the water are also important factors that can provide insights to the processes involved and their quantitative impact on the P status in shallow, eutrophic lakes.
Results Regarding the Food of the Planktic Crustaceans Daphnia hyalina and Eudiaptomus gracilis
Authors: Horn Wolfgang 
Published: February 2007

AbstractThe graph of maximum filtering and grazing rates versus particle size shows that Daphnia hyalina is a microfiltrator and Eudiaptomus gracilis is a macrofiltrator. In contrast to Eudiaptomus gracilis, Daphnia hyalina is also able to utilize larger bacteria (c. 1 μm3) as a food source.
Juvenile Anadromous Atlantic Salmon of Three Lakes of Newfoundland
Authors: Pepper V. A. , Oliver N. P. , Blundon R. 
Published: February 2007

AbstractAnadromous Atlantic salmon parr (Salmo salar) were captured from three Newfoundland lakes. Yearling and 2 year parr were captured most often in shallow water <2 m deep around lake perimeters and were not abundant at greater depths. The 3+ and 4+ parr age groups were rarely found inshore (<2 m) but were captured in deeper offshore areas. Though the parr population in one deep lake was too small to be estimated by mark‐recapture, estimates of the yearlings plus 2+ age groups in two shallower lakes were 55 and 63 parr ha−1. respectively. No under yearlings were found in lake habitats. Parr density in the three study lakes varied inversely with mean lake depth. Lacustrine parr growth rate was greater than or equal to that of stream dwelling parr. It is concluded that some shallow lakes of Newfoundland provide major rearing areas for juvenile anadromous Atlantic salmon.
Some New and Rare Freshwater Algae from Iraq
Authors: Nurul Islam A. K. M. 
Published: February 2007

AbstractOne new species of Sphaeroplea (S. bourrellyii Islam), and six taxa, hitherto unrecorded from Iraq, namely, Dichotomosiphon tuberosus (A. Br.) Ernst, Johannesbaptistia pellucida (Dickie) Taylor & Drouet, Microcoleus chthonoplastes Thuret ex Gomont, M. lacustris (Rab.) Farlow, Gloeotrichia longiarticulata G. S. West, and Ammatoidea (?) normanni W. & G. S. West are described and illustrated.
A Bloom of the Planktonic Diatom, Cerataulina pelagica, off the Coast of Northeastern New Zealand in 1983, and its Contribution to an Associated Mortality of Fish and Benthic Fauna
Authors: Taylor F. J. , Taylor N. J. , Walsby J. R. 
Published: February 2007

AbstractA bloom of Cerataulina pelagica dominated the sea area off the north‐east coast of New Zealand for three months in the summer of 1982–83, and has been related to unusually calm conditions associated with an unusually low Southern Oscillation Index. Deaths of benthic shellfish during the bloom were attributed to anoxia induced by the bacterial decay of the diatom cells. Death of bony fish caught on long‐lines was attributed to anoxia and the clogging of the gills with mucilage produced by the diatoms.
Evolution des populations bactériennes dans les sédiments des marais maritimes de l'Ile Grande pollués par I'Amoco Cadiz Evolution of Bacterial Populations in Salt Marsh Sediments of Ile Grande Polluted by Amoco Cadiz
Authors: Vacelet Eveline , Mille Gilbert 
Published: February 2007

AbstractMicrobial investigations on heterotrophic bacteria (MPN counts, adenylates charge, growth rate and enzymatic activities) and hydrocarbon utilizing microorganisms (MPN counts) were carried out during three years in the salt marshes of Ile Grande. The aim was to follow their recovery after oil pollution.Oil degradation is related to bacterial activity (depending on site, depth in the soil, redox level and hydrocarbon concentrations). The results for the three years show a significant enhancement of the microflora during the first year (corresponding to removal of n. alkanes) followed by a decrease in bacterial activity which persisted for over two years. The activity of the heterotrophic bacterial population is deeply disturbed compared with unoiled sites, and these shifts remain detectable three years after oiling. This study does not modify our previous estimation regarding the recovery of the salt marshes.
Food Size Spectra and Species Replacement within Herbivorous Zooplankton
Authors: Hessen Dag Olav , Nilssen Jens Petter , Eriksen Tone Oksum 
Published: February 2007

AbstractThe relationship between two commonly co‐occurring filter‐feeders; Bosmina longirostris and Eudiaptomus gracilis at different nutrient levels, was investigated in bag experiments in Lake Gjersjøen. At the start of the experiment, the numerical relationship between Bosmina and Eudiaptomus was less than 1 : 10, but during the experimental period, a strong increase in Bosmina and a corresponding decrease in Eudiaptomus and medium‐sized algae (5–25 μm) was observed. The shift from Eudiaptomus to Bosmina was probably due to strong competition on mediumsized algae while Bosmina in addition may utilize smaller algae and bacteria, not available to Eudiaptomus. Their coexistence in the lake at much lower densities is probably due to a strong selective fish predation, suppressing Bosmina.Daphnia longispina, not naturally occurring in the lake, showed strong competitive abilities in a fish‐free bag.
Fatty Acids in Lipids from Particulate Organic Matter in a Eutrophic Lake, Lake Nakanuma, Japan
Authors: Miyazaki Tatsuo , Irie Junko , Ogawa Yoshio , Ichimura Shun‐Ei 
Published: February 2007

AbstractThe depth profiles and seasonal abundance of fatty acids in lipids from the particulate organic matter in the eutrophic Lake Nakanuma, Japan, were closely related to both photosynthetic activity and the distribution of phytoplankton. The changes in the relative proportions of the fatty acids suggest that their synthesis is directly related to the photosynthetic activity of phytoplankton.
Analysis of the Inshore Macrozoobenthic Community in Lake Naini Tal, U. P., India
Authors: Gupta P. K. , Pant M. C. 
Published: February 2007

AbstractCertain parameters of the zoobenthos community structure, viz., population density, species richness, diversity, dominance and similarity indices in the inshore area (0–1 m stratum) of Lake Naini Tal were examined during 1978–1979. Significant changes in community structure were found both in space and time. A classification applied on similarity index values of the data from different sampling occasions showed two clusters of species–winter and summer clusters. Similar analysis of the sample data from different sites suggested three clusters of species for polluted water, clean water and intermediate sites. It is suggested that variation in the benthos community structure over the season is primarily related to temperature, availability of food and life cycle pattern, while its variation in space is related to sediment texture and degree of pollution.
On the Breeding Biology of Glyphidrilus annandalei MICHAELSON (Haplotaxida: Glossoscolecidae) and its Relation to the Various Physical and Chemical Factors
Authors: Sobhana S. , Nair N. Balakrishnan 
Published: February 2007

AbstractGlyphidrilus annandalei Michaelson exhibits a pronounced breeding period extending from September to November. Breeding individuals achieve their maximum frequency in September, when 50 per cent of the whole population was with fully developed clitellum. Studies on the physical and chemical conditions of the habitat revealed that breeding in this worm depends the monsoon of the area creating optimum conditions for the life and activities of the organism.
Ecology and Bioproduction in the Microphytobenthos of the Chain of Shallow Inlets (Boddens) South of the Darss‐Zingst Peninsula (Southern Baltic Sea)
Authors: Wasmund Norbert 
Published: February 2007

AbstractThe significance of epipsammic microphytobenthos bioproduction in a shallow estuary was investigated by the oxygen method. Bioproduction reached a maximum in May or June. A close correlation was found between the gross production rate and algal biomass at station K. The biomass and production rates were distinctly lower at station B than at station K as station B was more exposed. Circadian variations and depth profiles of the gross production rate correlated best with irradiation intensity. Mean gross production from April to October was 1761 O2.m−2 and 75 g C·m−2.
Periphyton (Aufwuchs) Communities of Ciliated Protozoa in Salt‐Polluted Running Waters of the Weser River Basin — Their Structure and Indicator Value (Including Model Ecosystems)
Authors: Albrecht Jürgen 
Published: February 2007

AbstractThe ciliates in aufwuchs communities on glass slides exposed to different amounts of salt pollution at several locations in the Weser River system were investigated. The results were compared with those from the study of model ecosystems exposed to salts. A comparison of the ciliate occurrence with a number of physical and chemical parameters showed that it is primarily the amount of salt present that determines which species are dominant. The number of species present decreases in the presence of high salt concentrations and in water flowing at a high velocity. A halobic index was formulated to indicate salt pollution quantitatively but turned out not to be useful due to the euryhaline potency of most of the ciliate species. The saprobic index can be used in rivers polluted with salt only if biological indicator species are present in sufficient number.
Community Structure of Macrobenthic Invertebrates in Sandy Beaches of the Jordan Gulf of Aqaba, Red Sea
Authors: Ismail Naim S. 
Published: February 2007

AbstractSix sandy beach stations along the Jordan Gulf of Aqaba were selected for macrofaunal examination during November 1980. Fifteen core samples (0.01 m2 to a depth of 10–15 cm) were taken at each station; five at the high tide line, five at the low tide line, and five midway.Twenty‐two taxa were encountered from all stations. Polychaetes were the most diverse group with seven taxa, followed by molluscs and crustaceans with six and five taxa respectively. Animal diversity, using the Shannon‐Wiener Index, was generally low. Based on the biological index value of McCLOSKEY (1970), seven taxa were considered the community dominants. These are: the polychaetes, Glycera tesselata, Pisione remota, Saccocirrus sp., and Perinereis nuntia; the isopod Eurydice arabica; a nemertean and an oligochaete.
Light/Dark Cycle and Temperature‐Their Impact on Phosphate‐Limited Growth ofOscillatoria redekeiVANGOORin Semicontinuous Culture
Authors: Wernicke P. , Nicklisch A. 
Published: February 2007

AbstractPhosphate‐limited growth ofOscillatoria redekeiin semicontinuous culture has been studied under conditions of continuous illumination at 20 °C as well as in a 12/12 hours light‐dark cycle at temperatures between 5 °C and 20 °C. The subsistence quota (q0) amounted to 0.052 μmol mm−3under all conditions, when the phosphate quota was expressed on the basis of cell volume. The interaction between temperature and phosphate quota and its impact on growth rate are described by the following model:equation imageParameter values aretopt=24.5 °C,tmin=0.95 °C, μmax=0.873 d−1. The maximum phosphate quota was found to depend on temperature and to increase along with declining temperature.
The Postglacial History of Lake Flarken, Southern Sweden, Interpreted from Subfossil Insect Remains
Authors: Brodin Yngve W. 
Published: February 2007

AbstractA correlation of changes in the composition of chironomid and chaoborid remains and changes in sediment chemical composition, floristic, and other faunistic information indicate that a decreasing productivity and an increasing humic level characterized the development of the small Lake Flarken, Southern Sweden, during the postglacial period. Pronounced changes in the fauna were correlated with fluctuations of the water level in the lake, which was caused by changes in the humidity of the climate. Significant human influence on the lake has only occurred in recent years, during which a rapid acidification has caused the most dramatic change in the fauna, by far, in the whole history of the lake.
The Relationship between Disease in Crassostrea virginica (GMELIN) and Thermal Effluents in the Chesapeake‐Delaware Bay Area
Authors: Tinsman Jeffrey C. , Maurer Don 
Published: February 2007

AbstractThe null hypothesis for this research was that oyster parasites and disease were not associated with increased thermal loading in the Chesapeake‐Delaware area. The American oyster Crassostrea virginica (GMELIN) was held at a reference station and a test station in the Chesapeake and Delaware Bay area for a year. Oysters from the four stations were sampled monthly for histological studies and parasite incidence together with the infestation of the polychaetous annelid Polydora websteri. The incidence of parasites and disease conditions from histology was negligible. Based on these results the null hypothesis was accepted, that oyster parasites and diseases did not increase with increased thermal loading. However, infestation of the oyster commensal P. websteri increased with increased temperature.
Seasonal Variations of Phytoplankton in a Series of Waste Treatment Lagoons (Chimkent, Central Asia). I. Artificial Inoculation and Role of Algae in Sewage Purification
Authors: Ergashev A. E. , Tajiev Sh. 
Published: February 2007

AbstractThe investigation deals with ways of increasing the number of species by means of artificial introduction of algae. After inoculation, the authors recorded 212 species and forms: 128 in spring, 165 in summer, 119 in autumn and 61 in winter. The maximal cell number of phytoplankton occurs in summer, the minimal in winter. The active role of algae in the sewage purification is shown.
Interrelationships among the Epipelon, Epiphyton and Phytoplankton in a Eutrophic Lake
Authors: Jenkerson C. G. , Hickman M. 
Published: February 2007

AbstractData from simultaneous studies of three algal communities (phytoplankton, epipelon and epiphyton) in an edaphically eutrophic lake are compared. Comparisons include both physical and chemical parameters along with those involving the biota.
Spatial Structure of the Insect Community of a Small Dimictic Lake in the Laurentians (Québec)
Authors: Harper P. P. , Cloutier Louise 
Published: February 2007

AbstractThe distribution of merolimnic benthic insects was studied in Lake Cromwell, a small (9 ha) and shallow (max. depth 9 m) dimictic lake with a summer hypolimnetic warming on the Laurentian highlands of Québec. Communities were described from 22 sets of emergence data. Two hundred and twelve species were recognized of which 153 were Chironomidae (Diptera). Through clustering and ordination techniques, five communities were recognized: one in the flooded shrub zone along the shore, two littoral, one sublittoral and one profundal. Differences between the communities were more quantitative than qualitative. The majority of species inhabited the shore and littoral stations, and only the hardiest reached the deepest zone. There were few species characteristic of the profundal, none of them abundant. Discriminating, dominant, and characteristic species were determined for each community, as were the ubiquitous species. There is a general decrease in species richness, species diversity and population density, and a change in community structure along the depth gradient. A discontinuity at 1–2 m is related to a sharp increase in Chaoboridae in the deeper waters.
The Epipelic Algal Flora of the River Wye System, Wales, U. K. 2. Algal Phyla and Species Population Dynamics
Authors: Antoine Samir E. , Benson‐Evans Kathryn 
Published: February 2007

AbstractThe Bacillariophyta dominated over the other phyla and were mainly recorded in high densities during summer and autumn. The Chlorophyta and Myxophyta (Cyanobacteria) were represented by coccoid forms and by non‐heterocystous, filamentous forms, respectively. Both were mainly recorded during summer and mostly absent during winter. Other phyla were occasionally recorded in low densities; the Chrysophyta being found in the River Elan and at one site on the River Wye during June 1980. Their members were considered as “contaminants” or “fall‐out” from other communities. Pennate diatoms were the most “constant” species and either showed a general upstream or downstream increase or a general distribution throughout the study area. Populations of the same species colonising both sediments and stones were not correlated or insignificantly correlated with each other at most stations. It was concluded that sediments were unsuitable for algal colonisation. The River Elan and upper Wye were rated as oligosaprobic, the River Ithon and lower Wye as β‐mesosaprobic and the River Lugg as α‐mesosaprobic.
Toxicité du cuivre vis à vis de Microcystis aeruginosa Kütz. et d'Aphanizomenon flos‐aquae Ralfs
Authors: Bertru Georges , Saout Marc Le , Gueune Yvon 
Published: February 2007

AbstractWe studied the toxicity of copper on Microcystis aeruginosa and Aphanizomenon flos‐aquae. The toxicity phenomena can be described by the survival dose relationship which allows us to define the three parameters: threshold concentration (Cs), sensitivity (k) and a NL. 50%. The latter corresponds to the copper concentration which reduces the number of cells at the end of the exponential phase by 50%.A. flos‐aquae is very clearly less tolerant than M. aeruginosa to copper. Viable cell counts based on electron transport activity showed that M. aeruginosa cultures can detoxify copper.
Statistics of the Underwater Light Field: An Empirical Model
Authors: Rørslett Bjørn 
Published: February 2007

AbstractThe underwater light field is described as a stochastic process, with the vertical attenuation as a random variable. It is shown that the vertical attenuation integral is well described as a Normal process with uncorrelated increments. The attenuation processes within a water body are found to be quite independent of the incoming irradiance. Thus, the relative light intensity at any depth can be approximated by a Lognormal random variable. Based upon the expectation of this Lognormal variable, and the mean value of the incident irradiance, the irradiance delivered at any depth can be estimated, as well as the statistical distribution of the irradiance.Light data from a number of Norwegian soft‐water lakes showed good fit to the model. Two productive lakes included in this study also had a light regime well described by the statistical model. However, the model should be extended to cater for seasonal variations in these applications.
Relative Protein Metabolism in Rotifer Brachionus calyciflorus PALLAS, in Relation to Temperature
Authors: Galkovskaya Galina A. , Ejsmont‐Kababin Jolanta , Evdokimov Vyacheslav N. 
Published: February 2007

AbstractIn the temperature range of 10 to 35°C the relationships of the oxygen consumption and nitrogen excretion rates to temperature in Brachionus calyciflorus PALLAS can be described by an exponential function where Q10 is equal to 2.45 or 2.18, respectively. Temperature adaptation within the range studied resulted in stabilisation of relative protein metabolism which accounted for nearly 50 per cent of the total metabolic loss.
Seasonality, Population Dynamics and Production of Daphnia longispina in the Subtropical Lake Bhimtal (U.P.), India
Authors: Sharma P. C. , Pant M. C. 
Published: February 2007

AbstractSeasonal variation in population density, birth rate, mortality and production of a daphnid was studied in a high, altitude sub‐tropical lake. A bimodal growth curve with maxima during summer and autumn was observed. A positive correlation was reported between fecundity and death rate, probably due to a difference in age specific death rate combined with a high relative frequency of juveniles in a growing population. The production of Daphnia longispina correlates better with temperature than with food. The P/B ratio was higher during summer and autumn months.
The Interaction of Selenate and Selenite with Selected Freshwater Sediments
Authors: Lipinski Norman George , Huang Pan Ming , Hammer U. Theodore , Liaw Wen K. 
Published: February 2007

AbstractSelenite and selenate at submicrogram levels were added to suspensions of two lake sediments (Buffalo Pound and Katepwa Lakes) from southeastern Saskatchewan, Canada. The sediment from Buffalo Pound Lake rapidly oxidized selenite in an Arrhenius type reaction and followed first order kinetics. The sediment from Katepwa Lake oxidized selenite, but at a much slower rate. The oxidation of selenite is an abiotic process. The sediment from Katepwa Lake also reduced selenate, while Buffalo Pound Lake sediment did not. The reduction of selenate is likely mediated by biotic activity, associated biochemical processes, and/or organic matter.