bluuebunny/crossref_metadata_2025 huggingface dataset:
Accumulation of Natural Radionuclides in the Bottom Sediments and by Aquatic Organisms of Streams
Authors: Justýn Jaromír , Stanêk Zdenêk
Published: February 2007

The accumulation of natural radioisotopes by aquatic organisms and bottom sediments was studied in two small rivers, one uncontaminated and the other polluted by effluents of uranium ore mining and milling.

Parabolic regressions between the water and uppermost sediment content of both uranium and total beta activity (corrected for 40K content) is presented and demonstrates the water cumulative capacity of organically rich sediments. For 226Ra no significant differences between sediments with different organic content were found. The 226Ra content of bottom sediments is expressed as a power function of radium and calcium concentration in the water.

In the given reaches, 53% and 85% of uranium and over 90% of 226Ra and total beta activity (corrected for 40K) was accumulated in the upper two centimetres of sediments and biomass of aquatic vegetation. Filamentous algae, plankton, aquatic bryophyta and macrophyta from the present and other published data showed rather higher cumulation capacities as compared with bottom sediments.
Seasonal Development of Phytoplankton in Fish Ponds
Authors: Fott Jan , Kořínek Vladimír , Pražáková Miroslava , Vondruš Bohumil , Forejt Karel
Published: February 2007

At the fish ponds under study the authors defined several types of plankton which have been frequently found during the season (April – October). These types are: Early‐spring maximum of phytoplankton, Depression of phytoplankton, Bloom of Aphanizomenon, Maximum of Chlorococcales.

The periods of “depression” seem to be typical for the managed carp ponds in the spring. They are characterized by the low density of rapidly reproducing algal populations (e. g. Cryptomonas) and by the dense populations of large cladocerans of the genus Daphnia. Chlorophyll in phytoplankton is less than 5μg/l, transparency is higher than 2 meters.

Periods of the spring depression may be followed by the maxima of either Aphanizomenon or Chlorococcales, with concentrations of chlorophyll increasing to 100 μg/l and more. The change from the phase of “depression” to the “maximum of Chlorococcales” is accompanied by decrease in numbers of Daphnia and increase in numbers of the small cladoceran species, but all the mechanisms responsible for the transition are not yet fully understood.
Untersuchungen zum Phosphatmetabolismus einer Trinkwassertalsperre
Authors: Hofmann Reiner
Published: February 2007

The examinations showed that the phosphate supply for the planktonic primary production comes almost exclusively from the influxes. The nutrient pool in the hypolimnion and in the sediment does not play a leading part. Evidently, that is often so in reservoirs.

Both the phytoplankton (the most frequent species are Asterionella formosa and Fragilaria crotonensis) and the concentration of phosphate fractions are subject to considerable seasonal variations. The Asterionella spring maximum, typical of this reservoir, is released directly or indirectly by meteorological factors. An adequate orthophosphate concentration is a basic condition which is accomplished, however, nearly every year. The autumnal Fragilaria maximum begins when a definite mixing depth hae been achieved. The breakdown of a diatom maximum is caused almost at all times by exhaustion of the phosphate reserves.
Notes on the influence of particulate organic matter (POM) on light conditions at a coral reef of the Australian great barrier reef
Authors: H. H. Kühlmann Dietrich
Published: February 2007

On the outer slope of a coral reef in the Great Barrier Reef, at a depth of 11‐12 in without artificial light, bright red and rose colours were observed to occur on coelenterates, because masses of floating luminescent bacteria in the environment.
Catalogue of the Microplankton in the gulf of marseilles
Authors: Travers Anne , Travers Marc
Published: February 2007

A large number of microplankton samples has been collected during every season in the Gulf of Marseilles from 1960 to 1968 (water samples and net tows). The authors have examined them with ecological, quantitative and qualitative purposes. Only the last one is considered here. About seven hundred systematic units have been identified. The most diverse taxonomical, groups are the diatoms and dinoflagellates, which exhibit much more numerous taxa than tintinnids, coccolithophorids and silicoflagellates.
Littoral Benthos of the Northern Baltic Sea. III. Macrobenthos of the Hydrolittoral Belt of Filamentous Algae on rocky shores in Tvärminne
Authors: Hällfors Guy , Kangas Pentti , Lappalainen Annikki
Published: February 2007

The community composition was studied quantitatively in two localities in 1968‐1970. The average ash‐free dry weights of the plants in a fully exposed and a moderately exposed locality were 48.6 g. m−2 and 93.3 g. m−2, respectively. The average animal ash‐free dry weights were 2.52 g. m−2 and 3.45 g. m−2. and the average numbers of animal individuals were 5360 m−2 and 15450. m−2.

The communities are characterized by the strong dominance of a few species. viz. Cladophora glomerata. Gammarus spp. and Chironomid larvae. The species diversity is thus very low. The seasonal aspects of species composition and abundance are presented. and some factors causing the differences between the localities are discussed.
Untersuchungen über das Phytoplankton und einige Umweltparameter des Shatt al‐Arab (Irak)
Authors: Kell Volkbert , A. H. Saad Massoud
Published: February 2007

Samples of phytoplankton were taken from the Euphrat and Tigris Estuary (Shatt al‐Arab) in April 1974 and investigated by means of the inverted microscope. Among 226 species identified in the samples 95 were of marine origin. The share of diatoms in the total numbers of cells from all stations amounted to 68%. The abundance of planktonic green algae amounted to 19%, of the blue greens to 13%. The number of marine species continuously increased in the longitudinal axis of the 139 km section considered. The data of the phytoplankton were compared with the gradation of some environmental variables (temperature, transparency, dissolved oxygen, chloride). Regular longitudinal or vertical differences of these parameters were not observed.
Food consumption and utilization in two freshwater cyclopoid copepods (mesocyclops edax and cyclops vicinus)
Authors: Brandl ZdenêK , Fernando C. H.
Published: February 2007

The predatory feeding of Mesocyclops edax and Cyclops vicinus was studied using the 14C‐labelled Ceriodaphnia and some other kinds of the crustacean zooplankters. When given a choice, both species exhibited clear selection of smaller specimens of prey. The feeding rates depend on the kind of prey. The daily ration for the prey readily accepted by Mesocyclops was roughly equal to the predator's biomass, while it was only one half or one third of the body biomass in Cyclops vicinus. Only about one third of the killed biomass was actually ingested and 21–32% was assimilated when the copepods preyed upon the cladocerans or the copepodid larvae. When fed with naupliar larvae the cyclopoid copepods assimilated over 70% of the killed biomass. Almost one half of the freshly assimilated carbon passes through the short term cycle and is quickly respired and excreted.
Community patterns on a submerged barrier reef at Barbados, West Indies
Authors: Ott Bruce
Published: February 2007

A quantitative survey of a submerged barrier reef was undertaken in Barbados, West Indies, over a two year period (1971–73). Photo‐line transects were employed to obtain coverage data on corals and other benthic organisms. Light, sedimentation, currents, oxygen, temperature and salinity were also monitored.

Results indicate corals cover about 30 per cent of the bottom with living colonies; another 7 per cent is contributed by other zoobenthos. The most abundant coral species are Montastrea annularis, M. cavernosa and Siderastrea siderea, each contributing between 4 and 5 per cent of bottom cover. Light is the only physical factor monitored that correlated significantly with biomass; sedimentation may have a secondary effect. Most of the barrier reef is composed of mixed coral associations forming a biologically accommodated community.

Comparisons are made between the barrier reef in Barbados and deeper reefs in Jamaica and Curacao. Reefs are, in the main, similar but coral species and community structure differences do occur.
Faunistisch‐ökologische Untersuchungen am Meiobenthos des Saaler Boddens (Darßer Boddenkette), Ostsee
Authors: Beschnidt Jochen , Noack Bodo
Published: February 2007

The meiofauna of the Saaler Bodden was investigated in the period from September 1969 to April 1970. The Saaler Bodden is that part of a brackish water area which is situated farthest from the Baltic Sea. In the southern part we usually find fresh water; in the northern part, the salinity rises to a maximum of 5 to 6‰. The authors give a short review of the hydrographical and biological peculiarities of the Saaler Bodden followed by remarks as to the qualitative and quantitative distribution of the meiofauna. Abundance and biomass are determined for Nematoda, Oligochaeta, Ostracoda, Copepoda, Harpacticoidea, Halacarida and Chironomid larvae. Oligochaeta and Ostracoda are dealt with in detail. The ecological requirements of the different species are discussed in this connection and their role in the balance of matter of this water body is pointed out.
Phytoplankton Population Efficiency Studies
Authors: Hickman Michael
Published: February 2007

Experiments designed to determine the photosynthetic capacity and efficiency of the phytoplankton of a small body of water were performed for a twelve month period. The experimental design was able to distinguish between actively growing large populations and those which were senescent.
Complete Carbon and Nitrogen Budgets for the Carnivorous Amphipod, Calliopius laeviusculus (KRØYER)
Authors: Dagg Michael J.
Published: February 2007

The marine amphipod Calliopius laeviusculus was grown in the laboratory under maximum food levels at 8°C, 12°C, and 15°C. The effects of body size and temperature on all budget parameters were determined and equations describing each parameter as a function of body carbon and nitrogen content were used to construct and check the balance of the budgets. The energetics of the amphipod are discussed.
Effects of the Amount of Food on Duration of Stages, Mortality Rates, and Size of Individuals in Tropisternus lateralis nimbatus (SAY) (Coleoptera: Hydrophylidae)
Authors: Hosseinie Shidokht O.
Published: February 2007

Larvae of Tropisternus lateralis nimbatus (SAY) were reared in the laboratory using different feeding regimes. Controls were fed as many mosquito larvae as they would readily eat until the later larval stages. Experimental groups were reared on a reduced number of larvae per day. The duration of stages, growth ratios, mortality rates, and elytral lengths in the control and experimental groups are compared.
Der Jahresgang von Neuston im Golf von Neapel
Authors: Hartmann Jürgen
Published: February 2007

The annual fluctuations in the occurrence of 91 taxa which were identified, made the recognition of 4 main seasonal populations possible. Trends were observed, as well as analogies to other patterns of distribution. On an average, more than half of the fauna was displaced from month to month, but the variation in the density of subtropical neuston appeared to be less over an annual period than it was during the day, and from region to region. The dominance of certain species and occurrence of neuston throughout the year demonstrated, that regionally at least a biocoenosis exists continously at the surface of the sea.
Stability in a Plankton Model
Authors: Shar Albert O.
Published: February 2007

A technique for analyzing the stability of a phytoplankton‐nutrient interaction model is described which may be applicable to a broader range of models. It is shown that periodicity of solutions in a differential equation does not imply the same for the corresponding difference equation model.
Comparative Studies on the Developmental Stages of Three Species of Tropisternus (Coleoptera: Hydrophilidae)
Authors: Hosseinie Shidokht O.
Published: February 2007

The egg cases, eggs, and different stages of life cycles of Tropisternus lateralis (Fabricius), T. blatchleyi D'Orchymont, and T. collaris (Fabricius) are described. A table is given for separating the various developmental stages of the three species.
Capacité photosynthétique du phytoplancton de la couche aphotique dans le fjord du Saguenay. Photosynthetic Capacity of Deep Phytoplankton in the Saguenay Fjord
Authors: Cǒte Raynald , Lacroix Guy
Published: February 2007

Abnormally high chlorophyll values have been observed in the deep layer of the Saguenay Fjord, Québec, Canada. Experiments were conducted to assess the capability of this darkened phytoplankton to photosynthetize upon reillumination. It was found that photosynthetic capacity is well retained by deep phytoplankton of the Saguenay, as shown by relatively high production rates, a low tidal variability of these rates and very high P : B ratios.
Some Factors Affecting on Dry Weight, Organic Weight and Concentrations of Carbon and Nitrogen in Freshly Prepared and in Preserved Zooplankton
Authors: Omori Makoto
Published: February 2007

Effects of rinsing and preservation on dry weight, organic weight, and chemical composition were determined on the chaetognath Sagitta nagae and the copepods Calanus sinicus, Pleuromamma xiphias and Acartia tonsa. Samples rinsed with distilled water were always lighter than comparable samples rinsed with seawater, showing apparent decrease in the organic matter and chemical contents (as total carbon and nitrogen) by weight; these losses increased with increasing volume of the rinse water. The volume of distilled water used for rinsing should be less than 0.3 ml per 1 mg dry weight of sample in order to avoid the significant loss of body substances. Isotonic ammonium formate rinse often resulted in the widest range of variation and on an average the organic weight and chemical contents were slightly lower than those of fresh samples rinsed with filtered seawater. Freeze‐drying samples resulted in dry and organic weights as well as chemical compositions that were somewhat greater than oven‐dried samples. The organic matter and chemical contents by weight decreased significantly within 2.5 days of being placed in Borax‐buffered formaldehyde‐sea water solution. Loss of organic weight from fresh samples exceeded 20% after one week of the preservation. Hexamine‐buffered formaldehyde solution showed a result which was different from the Borax‐buffered solution.
Facteurs limitant la production primaire des eaux oligotrophes d'une aire eôtière méditerranéenne (Calanque d'En‐Vau, Marseille). Factors Limiting the Primary Production of Oligotrophic Waters in a Mediterranean Coastal Area (Calanque d'En‐Vau, Marseilles)
Authors: Berland B. R. , Bonin D. J. , Maestrini S. Y.
Published: February 2007

The importance of different factors involved in the limitation of primary production in oligotrophic Mediterranean waters were investigated, through both nutrient and production estimations and algal bioassays. All the results obtained show that phosphorus is the main limiting factor of algal production. Nitrogen and chelating substances appear to be less limiting and vitamins play a small role. Light and temperature were not limiting, but higher temperatures were responsible for increased physiological activities of the phytoplankton. Previous results from the literature and those reported allow the authors to conclude that, as far as primary production is concerned, the northwestern part of the Mediterranean Sea differs from the large oceans.
Composition and Structure of Zooplankton Communities in Eighteen Arctic and Subarctic Lakes
Authors: Moore James W.
Published: February 2007

The factors influencing the composition and structure of zooplankton communities in 18 lakes in the Canadian arctic and subarctic were determined during 1975 and 1976. Phytoplankton were consumed in very low numbers by all species (Diaptomus sicilis, Heterocope septentrionalis, Cyclops scutifer, Daphnia longiremis, Bosmina longirostris, Holopedium gibberum, Keratella cochlearis, Kellicottia longispina) and therefore differences in algal productivity among the lakes had little effect on the zooplankton. Variations in surface area, maximum water depth, pH and the ionic composition of the water were also unimportant in controlling the communities. However, low temperature exerted strong influence over the diversity, abundance, fecundity and vertical distribution of most species.
The Distribution of Particulate Organic Carbon in the Oceans: Ecological Implications
Authors: Wangersky Peter J.
Published: February 2007

Distribution of participate organic carbon (POC) in the oceans appears to be in the form of small “clouds” high in POC superimposed on lower background values typical of depth and water mass. The background values display an exponential decrease with depth. Samples taken at close intervals, both vertical and horizontal, suggest that the extent of these clouds in water below the photic zone must be less than a meter in any dimension. The concentration of POC in the clouds is of the same order as that found in surface waters. Feeding behaviour of the larger zooplankton may involve active searching for these patches; the organisms should be examined for evidences of mechanisms for finding patches. The maximum distance between patches, even in deeper water, must be of the order of a few tens of meters.
Automated Phytoplankton Analysis by a Pattern Recognition Method
Authors: Uhlmann D. , Schlimpeet O. , Uhlmann W.
Published: February 2007

An automated image processing and pattern recognition system was applied to the identification of the following genera exhibiting distinct differences in shape: Asterionella, Melosira, Fragilaria, Ceratium, Peridinium. The classification structure developed by a computer program was able to attribute all colonies or cells considered to the corresponding genus.
Limnological Studies on the River Tigris, Iraq. II. Seasonal Variations of Nutrients
Authors: Saad Massoud A. H. , Antoine Samir E.
Published: February 2007

Regional and seasonal variations of nutrients in the 630 km stretch of the lower Tigris were studied and discussed. The lowest average values for nitrate and phosphate, found in July and October respectively, were correlated mainly with the high rates of uptake by phytoplankton. The lowest average concentration of silicate, recorded in July, can be related principally to the considerable increase in diatom density. Additional nutrients entered into the River Tigris in January through land runoff and in April with the flood waters. The average concentrations of nitrate and phosphate showed an inverse relationship. The average nitrate: nitrite ratio varied from 0.07 : 1 to 782.0 : 1 and the average nitrate : phosphate ratio ranged from 0.01 : 1 to 7.90 : 1.
Le traîneau suprabenthique MACER‐GIROQ : appareil amélioré pour l'échantillonnage quantitatif étagé de la petite faune nageuse an voisinage du fond The MACER‐GIROQ Suprabenthic Sled: An Improved Device for Quantitative Two‐level Sampling of the Small Swimming Fauna near the Bottom
Authors: Brunel P. , Besner M. , Messier D. , Poirier L. , Granger D. , Weinstein M.
Published: February 2007

Enlarged versions of the MACER sled‐mounted suprabenthic sampler were tested, improved, calibrated and used extensively (598 tows) at depths of 10—384 m since 1968 in the Gulf and Estuary of the St. Lawrence. Two half‐metre zooplankton nets are mounted at 28—64 and 106—142 cm from the sea‐bed, on a steel chassis and toboggan plate. Each has a flow‐meter and 3 horizontal shutters which open via a lever upon contact with the sea floor. They close automatically, through springs and water pressure, whenever the sled leaves the bottom, ensuring uncontaminated suprabenthic samples. Although heavy (228 kg), the device is sturdy, used like a beam trawl, reliable, and collects very little sediment. It has been used to study micro‐stratification above bottom. Data on filtered water volumes, special problems encountered and future improvements are discussed.
Diel Patterns of Phytoplankton Productivity and Extracellular Release in Ultra‐Oligotrophic Lake Tahoe
Authors: Tilzer Max M. , Horne Alexander J.
Published: February 2007

Phytoplankton in Lake Tahoe is dominated by diatoms and chrysophytes. High water transparency permits photosynthesis to a maximum depth of over 100 m. Average annual primary production rates in the entire trophogenic zone are 0.5–0.6 g C m−3 year−1.

Nutrient concentrations and biomass parameters showed little diel variation. Photosynthesis in mixed water columns decreased in the afternoon. This decline can be attributed to inactivation of algae by overoptimal light during mid‐day hours. As the summer season progressed, algae became adapted to high light intensities and thus were less susceptible to light inhibition. Extracellular release by algae averaged 12.5 ± 7.4% of assimilated carbon without significant vertical differences. Damage of cells by light thus can be excluded. Respiratory losses overnight comprised at least 30% of the carbon assimilated during the preceding day. Integral photosynthesis showed a logarithmic relationship to incident light which can be used to predict daily production rates from mid‐day incubation with an error of well below 10%.
Niche Modification in Chaetognatha Infected with Larval Trematodes (Digenea)
Authors: Pearre Sifford
Published: February 2007

Infection by larval trematode parasites caused sympatric chaetognath species to live nearer the surface than normal, hence to select more upper water prey than did non‐parasitized chaetognaths of the same species. This was associated with contagious distribution of parasites within the population.

Trematode larvae appear as opaque objects in their almost transparent chaetognath hosts. Since they also induced their hosts to be larger and to live in better‐lit habitat than non‐parasitized ones, the parasites render their hosts more conspicuous and thus probably more susceptible to sight hunting fish predators. Available data from seasonal cycles of parasitism in chaetognaths confirms that trematode‐parasitized chaetognaths suffer higher mortality than normal, probably ascribable to predation. However, the size increase also may discourage predation by smaller, incorrect final host species.

Localization of parasitism (which lowers individual reproductive potential). and predation in the same segment of the population should minimize loss of reproductive potential for the chaetognath population as a whole. This conservation of host resources can be considered primarily of benefit to the trematodes.

Knowledge of parasite‐induced host modification should enable prediction of mode of parasite transmission, and vice‐versa. Contagious distribution of parasites in their host populations can help damp population cycling.
Hesionides riegerorum n. sp., a New Interstitial Freshwater Polychaete from the United States
Authors: Westheide Wilfried
Published: February 2007

Hesionides riegerorum n. sp. is a new freshwater polychaete species. It was found in considerable numbers in the interstitial habitat of sandy banks of the Chowan River in North Carolina, USA. There are no general differences in the organization and behavior compared to the marine species of this genus. The new species, however, is unequivocally distinguished from them by slight quantitative differences and more striking qualitative features. The localities not far from the coast point to an immigration path for this freshwater polychaete that has been shown also for most of the other marine interstitial immigrants: directly from sandy intertidal beaches along brackish estuaries into the limnopsammal.
Numerical Abundance and Biomass of Bacteria, Algae and Macrobenthos of a Large Northern River, the Athabasca
Authors: Barton David R. , Lock Maurice A.
Published: February 2007

The benthic flora and fauna of a large, turbid, northern river was sampled in autumn. Macroinvertebrate communities on bedrock resembled those of smaller streams but specialized Chironomidae larvae dominated sandy substrates. Bacterial densities on rocks were within the ranges reported from smaller streams. Benthic primary production is probably limited by high turbidity so that most of the energy available to benthic communites is probably allochthonous in origin.
Hydrologic and Total Phosphorus Budgets of A Small West Virginia Impoundment
Authors: Labaugh James W.
Published: February 2007

Hydrologic and total phosphorus budget data were obtained during a 24 month period for Spruce Knob Lake, Randolph County, West Virginia. Total phophorus retention was approximately 36% of input for both years despite differences in flushing rate. Based on total phosphorus and hydrologic data, Spruce Knob Lake is eutrophic. Predicted spring total phosphorus concentrations from the Dillon‐Rigler nutrient budget model were in close agreement with actual observed concentrations. Application of literature models predicting total phosphorus retention based on flushing rate to Spruce Knob Lake data resulted in close agreement with actual retention values. Models based on hydraulic load were inadequate when applied to Spruce Knob Lake. Relative phosphorus residence time values (lake total phosphorus/inflow total phosphorus). for both years indicated that the lake has a low sedimentation rate. Mass balance data confirmed this low rate of sedimentation.
Assimilation de composés organiques dissous dans le secteur antarctique de l'Ocean Indien.
Authors: Jacques Guy , Cahet Guy
Published: February 2007

Uptake of Dissolved Organic Compounds in the Antarctic Sector of the Indian Ocean

The kinetic approach was used to determine the heterotrophic potential of the Indian Antarctic waters for three dissolved organic compouds: glucose, proline and glutamate. Variations with depth and latitude are discussed.
An Annotated List of the Stoneflies (Plecoptera). of the Soviet Far East
Authors: Levanidova I. M. , Zhiltzova L. A.
Published: February 2007

The 101 species of the order Plecoptera known to inhabit the Soviet Far East are listed, and the geographical distribution, as far as known, is provided for each. Information about the habitat preferences is also presented. The zoogeographical factors that contributed to the establishment of the present ranges are mentioned, and the relationships within some of the genera are discussed.
The Effect of Parrotfish (Scaridae) on Coral in Barbados, W. I
Authors: Frydl Paul
Published: February 2007

Among the five species of parrotfish studied, only largeSparisoma viride (and rarely large Scarus vetula) graze on live coral. Of the several species of corals grazed, Montastrea annularis is grazed most extensively, and variations in its form may be the result of grazing scars. Parrotfish feeding on algae at the bases of the corals Madracis mirabilis and Porites porites break off the corals. This attack causes recession of the stands of M. mirabilis at an average rate of 1 cm/month.
Analysis of Plankton Dynamics in a Southwestern U.S.A. Reservoir Using ATP Assays
Authors: Boswell J. T. , Perry W. B. , Stanford J. A.
Published: February 2007

Plankton biomass in size segregated (i.e. 0.45–10 μm, 10–64 μm, 64–165 μm, and > 165 μm) samples was measured using ATP assays for two years in H. H. Moss Reservoir. The presence of variable numbers of microcrustacean zooplankton in the > 165 μ size class introduced significant, and perhaps inaccurate, variance into temporal dynamics of total ATP concentrations. As many as six physiochemical parameters, measured during 1975–76, were required to produce a significant multiple regression against ATP concentrations; a significant correlation between total ATP measured in the photic zone and surface temperature was observed. A large standing crop of nannoplankton (i.e. 0.45–10 μm) existed in the anaerobic and aphotic hypolimnion during summer stratification both years. This suggested that microbial heterotrophy was an especially important primary trophic event in the reservoir. Particulate (POC) and dissolved (DOC) organic carbon were measured in 1976–77. Organic carbon (POC + DOC) regressed significantly against ATP concentration in the 0.45–10 μm size class and microbial biomass (i.e. 0.45–165 μm) averaged 32 per cent of POC. When biomass was monitored over 24‐hour periods in the photic zone, significant changes were documented in various size classes, especially nannoplankton; but total microbial biomass remained relatively constant.
The Role of Predation in Causing Major Changes in the Limnology of a Hyper‐Eutrophic Lake
Authors: Leah R. T. , Moss Brian , Forrest D. E.
Published: February 2007

An experiment was carried out by separation of a shallow man‐made lake into two basins with an earth dam. Unintended leaks allowed extremely fertile river water to feed both basins so that nutrients were unlikely ever to have been limiting to phytoplankton populations. The two basins had greatly differing fish populations. In the basin in which these were low, a chain of events took place in which zooplankton grazing reduced phytoplankton growth sufficiently to allow establishment of aquatic macrophyte populations and an associated diverse benthic invertebrate community. In the basin to which fish had free access from the river, phytoplankton populations remained high, and no aquatic macrophyte community developed. The implications of these observations for shallow lake management are considered.
Influence of Hydrological Factors on the Seasonal Abundance of Phytoplankton in Kinjhar Lake, Pakistan
Authors: Nazneen Saiyida
Published: February 2007

The correlation of various hydrological factors with the distribution of phytoplankton and bacteria has been studied in Kinjhar Lake, situated 120 km north of Karachi. This lake is highly eutrophic, containing rich concentrations of nutrients, but the temporal distribution of phytoplankton was generally related to the variations of light and temperature. The effects of light and temperature are perhaps modified by nutrients, particularly when nitrogen and phosphorus are present in surprisingly low concentrations. The effect of mechanical disturbances in the artificial lake also has a significant effect on the growth of phytoplankton and indirectly on consumers, especially fishes.
Relationships Between Abundance of Insects and Standing Crop of Coarse Detritus in a Pennsylvania Stream
Authors: Miller Lee S. , Kovalak William P.
Published: February 2007

Relationships between insect abundance and standing crop of coarse detritus, which was estimated both volumetrically and gravimetrically, were studied in a second‐order stream (Little Sugar Creek, Pennsylvania) between June 1977 and June 1978. For individual taxa, coefficients of determination (R2) for relationships between insect abundance and standing crop of detritus were significant (P≦0.05) in 39% (by volume) and 32% (by weight) of the cases. Deposit feeding collectors accounted for only 41% of the significant R2 values. For total fauna, R2 values were significant (P≦0.05) on 7 of the 11 dates (by volume) and on 8 of the 11 dates (by weight).
Investigations on the Problem of Scale Reduction and Sulphate Tolerance of West Anatolian Cyprinodonts (Pisces)
Authors: Grimm Helmut
Published: February 2007

Scale reduced populations of the Turkish species Aphanius anatoliae are usually found in biotopes containing magnesium and sodium sulphate. According to the hypothesis by Aksiray & Villwock (1962), there is a correlation between the adaptability to sulphate containing water and the scaly covering – a process which could be interpreted via pleiotropic gene effects. In laboratory experiments, the influence of sulphates on the ontogenetic development of the species A. anatoliae (5 populations), A. iberus, A. dispar, and A. mento was investigated. No difference in the salt tolerance of scale reduced fish and normally scaled fish was observed. In addition, the number of scales in the central lateral row do not support the hypothesis either. The scale reductions are discussed to be a consequence of processes of regressive evolution.
Benthic Invertebrates Associated with a Serpulid Polychaete Assemblage in a Temperate Estuary
Authors: Haines Judith Lynn , Maurer Don
Published: February 2007

Hydroides dianthus(Verrill), a serpulid polychaete which secretes calcareous tubes, provides microhabitats for a variety of benthic invertebrates in Delaware Bay. These microhabitats function as biologically generated refuges and physical heterogeneities for at least 54 species. Dominance was measured by the biological index value which yielded 12 taxa that comprised 90% by number of the serpulid assemblage. These taxa included seven polychaetes, two amphipods, Nematoda, Oligochaeta, and Harpacticoida. In addition to the refuges provided by the serpulids, it was concluded that this temperate serpulid assemblage was comparable in function but not scale to calcareous biogenic assemblages in lower latitudes.
Composition of Benthic Invertebrate Communities in Relation to Phytoplankton Populations in Five Subarctic Lakes
Authors: Moore James W.
Published: February 2007

The effects of algal food supply, temperature, water depth and lake size on the composition of benthic invertebrate communities were determined during 1978 und 1979 in 5 lakes in the Canadian subarctic. The lakes varied widely in physical conditions and trophic level, with peak algal densities ranging from 40 to 2100 mg/m3 during the summer and 10 to 750 mg/m3 in the winter. The correlation coefficients between the size of the populations of herbivorous chironomids (Chironomus riparius, Ch. plumosus, Ch. decorus, Tanytarsus xanthus) and the density of algae during the winter were highly significant and positive. There were also positive, albeit weak, correlations with the summer growth of algae, temperature, depth and lake size. In addition, the seasonal appearances of fourth instar larvae in the sediments were positively correlated with peaks in the abundance of phytoplankton. In contrast, algal food supplies probably had little impact on the density of oligotrophic indicator species (Heterotrissocladius oliveri, H. changi, Protanypus ramosus, Pontoporeia affinis) and were replaced in importance by temperature and water depth. Variations in the densities of the main oligochaete species (Uncinais uncinata, Arcteonais lomondi, Limnodrilus claparedeianus) and mollusc species (Valvata sincera helicoidea) could not be related to any of the factors that were measured. The diversity of the communities was probably limited by low temperatures, whereas food supply, lake depth and lake size had little impact on the fauna.
The Manna Effect: A Model of Phytoplankton Patchiness in a Regenerative System
Authors: Wangersky Peter J. , Wangersky Charles P.
Published: February 2007

A Monte Carlo model for the growth of phytoplankton in a regenerative system has been constructed. This model assumes that nutrients are regenerated randomly in time and space at the scale which is important to the individual organisms. Under such a regime, organisms originally arrayed in a random fashion assume a patchy distribution within fifteen or twenty divisions, with some species becoming nonrandom in their distribution within five divisions. Other factors, physical or biological, may also induce or enhance patchiness, but normal regenerative processes in a nutrient‐limited system are sufficient in themselves to explain the phenomenon. Patchiness should be considered as the normal state for nonmotile organisms.
Signal Analysis of Irradiation, Temperature and Primary Production in a Small Artificial Pond: I. The Annual Signals
Authors: Lingeman Robert
Published: February 2007

This paper provides an example of some initial steps in signal analysis applied to a simple aquatic ecosystem in the form of a small artificial pond. Irradation, water temperature and dissolved oxygen concentration were continuously recorded over a two year period. Following the definition and discussion of several related parameters, an analysis procedure for trends and forced annual patterns was proposed and carried out. The annual pattern of photosynthetic fixation of solar energy is characterized by the annual level transfer efficiency, and for the periodic part of the process, by the transfer gain and phase shift. The possible role of temperature is briefly discussed.
Nitrogen Fixation During Blooms of Nodularia in Coastal Waters and Backwaters of the Arkona Sea (Baltic Sea) in 1974
Authors: Hübel Helmut , Hübel Marianne
Published: February 2007

Nitrogen fixation was investigated by means of the acetylene reduction method during the development of a water bloom of Nodularia in coastal waters of the Baltic Sea west of the island of Hiddensee and in backwaters showing different degrees of eutrophication. Depending on plankton density, the values found varied greatly. The maximum of nitrogen fixation values found in extremely dense water blooms under special conditions (Baltic Sea, 2250 μg N2/l · h; Kleiner Jasmunder Bodden, 374 μg N2/l · h) are up to 103 times higher than from other parts of the Baltic Sea or from inland waters. The average nitrogenase activity determined for coastal water populations of the Baltic Sea is 2.15 pg N2/heterocyst · h and that of the inmost backwaters 0.77 pg N2/heterocyst · h. The relationship between N2‐fixation and nutrient content in water is discussed.
Distribution, Abundance and Life Cycles of Oligochaeta from the Marine Hygropsammal with Special Reference to the Phallodrilinae (Tubificidae)
Authors: Pfannkuche Olaf
Published: February 2007

Tubificid and enchytraeid oligochaetes are common members of the interstitial fauna of sandy beaches. Their abundance dynamics, life cycles and distribution patterns were investigated at two beaches on the western Baltic Sea and at a North Sea beach (Isle of Sylt). Populations of 115,000 ind./m2 were found at protected Baltic beaches. Reproduction of the tubificids, Phallodrilus monospermathecus and Spiridion insigne takes place within a well defined breeding period once a year. The market horizontal and vertical distribution patterns of various tubificid and enchytraeid species are elucidated by preference reactions to several physiographic parameters, such as oxygen and water content of the sediment, and salinity.
Seasonal Changes in the Quantity and Nitrogen Content of Coarse Detritus in a Southern Ontario Stream
Authors: Wakefield Robert H. , Harrison Arthur D. , Kovalak William P.
Published: February 2007

Seasonal changes in standing crop of coarse, benthic detritus at five locations across a second‐order stream were studied between May 1971 and May 1972. Standing crop near the banks varied seasonally with highest quantities in the autumn and winter, whereas near midstream seasonal changes in standing crop were negligible. Mean annual standing crop was 747 g/m2 (ash‐free dry weight) near the banks and 225 g/m2 (AFDW) at midstream. Deposition experiments showed that standing crops of detritus came to equilibrium in 2–3 days at midstream and in about one week near the banks. Nitrogen content of coarse detritus, which ranged between 0.65 and 3.51% (AFDW), did not vary seasonally but was significantly greater near the banks than at midstream.
Signal Analysis of Irradiation, Temperature and Primary Production in a Small Artificial Pond. II. The Residual Spectra
Authors: Lingeman Robert
Published: February 2007

Irradiation, water temperature and dissolved oxygen of a small artificial pond were continuously recorded over a two year period. Following the elimination of previously estimated mean trends and forced annual patterns (LINGEMAN 1980) a spectral analysis procedure is proposed and executed for the residual signals of total diurnal irradiation, diel mean temperature and diurnal gross primary production. The residual power spectrum of diurnal irradiation was shown to be essentially the one of a white noise. Several higher frequencies were significantly present in both the signals of temperature and production. Some consideration is given to the cross correlation between the latter two parameters.
Synthèse et dégradation des composés glucidiques au sein de la communauté planctonique en zone marine eutrophe
Authors: Cahet G. , Crassous P. , Neveux J. , Rassoulzadegan F.
Published: February 2007

A general study on the relations between “phytoplanktonic excretion” and “heterotrophic assimilation” has been carried out in eutrophic systems, natural or artificial. In the complex systems of these relations, two types of heterotrophic responses were obtained according to prevailing algal species.

High heterotrophic potentials in NW African upwelling show the role of microorganisms in the disappearance of freshly excreted organic substances and in the composition of the remaining organic matter.
The Spawning and Early Life History of the Pollan (Coregonus pollan THOMPSON) in Lough Neagh, Northern Ireland
Authors: Dabrowski Konrad R.
Published: February 2007

Studies had been carried out on the local non‐migratory whitefish. Spawning behaviour and light conditions on the spawning ground are recorded. After artificial spawning, embryonal development took place under controlled conditions and the larvae were reared. Detailed characteristics of swim bladder creation and differentiation of the digestive tract are given. Distribution and number of pollan larvae near the spawning area and in the open lake were examined. Data are presented concerning the growth rates of larvae and fry in captivity and under lake conditions. Ecological data related to other coregonids are discussed and compared with the present study.
Stocking Rate Estimations of Tilapia mossambica Fingerlings for some Inland Reservoirs of Sri Lanka
Authors: Wijeyaratne M. J. S. , Costa H. H.
Published: February 2007

The Morphoedaphic Indices for several Sri Lanka inland water bodies (mostly ancient man‐made reservoirs) were calculated using conductivity and depth data. The relationship between Morphoedaphic Index MEI and the annual catch of fish C was found to be

.

Using this equation, the annual potential yields were calculated. The stocking densities of Tilapia fingerlings needed to be stocked were then estimated taking into consideration the natural recruitment of fingerlings from the already existing stocks of reproducing Tilapia.
Ecological Distribution of Polychaetous Annelids from the New England Outer Continental Shelf, Georges Bank
Authors: Maurer Don , Leathem Wayne
Published: February 2007

Four hundred and eight quantitative grab samples collected during the winter and spring of 1977 from the New England Continental Shelf (Georges Bank) yielded 333 species of polychaetes. Polychaetes comprised 53.8% of the number of all infaunal species, 53% of the density, and 60.5% of the wet weight biomass for all soft‐bodied organisms, at least for the winter. Mean number of species and mean density was significantly higher in the spring than in the winter. Mean values of number of species, H', SDN, density, and biomass were associated with various environmental factors. Based on numerical classification (normal and inverse) five polychaete site groups were identified. To a great extent these site groups were molded by major physical, geologic and biologic processes which influence the productivity of this ecologically and economically important area.
Studies on the Age and Growth of an Air‐breathing Catfish, Clarias batrachus (LINN.)
Authors: Thakur Nirmal K.
Published: February 2007

Age and growth of Clarias batrachus have been studied through the checks observed on the transverse sections of the pectoral spines of the fish. It was found that the checks are laid annually during July—August. The relationship between the total length and spine radius of the fish was found to be linear in the logarithmic form. Based on this relationship, a formula for back calculation of lengths at different ages was derived. The growth of the species appeared to conform to the inverse exponential pattern and could be expressed as:

Fairly good agreement was observed to exist between the lengths of the fish at corresponding ages calculated by the spine study, length‐frequency analysis and the empirical growth equation of VON BERTALANFFY.
Adaptation of Bathynellacea (Crustacea, Syncarida) to Life in the Interstitial (“Zoea Theory”)
Authors: Schminke Horst Kurt
Published: February 2007

This study aims at demonstrating that the Bathynellacea arose by neoteny from a zoea‐like ancestor (“Zoea Theory”). Bathynellacea basically have a larval morphology. Their post‐embryonic development passes through phases which are directly comparable with some in the development of primitive Eucarida. These phases are called the parazoeal and bathynellid phase, and correspond to the protozoeal and zoeal phase of Penaeidea, respectively. Running initially parallel to that of Penaeidea, the development of the Bathynellacea breaks off precociously. They reach sexual maturity at a stage which, in the Penaeidea, is followed by metamorphosis. There are reasons to assume that the development of all Syncarida originally passed through a series of free‐living larval stages and underwent metamorphosis. The bathynellaceans reach adulthood at a stage which corresponds to the last larval stage of their ancestor. The ecological path to interstitial life of the Bathynellacea and the bearing of the “Zoea Theory” upon views as to their phylogenetic position are discussed. The classical example of a group of crustaceans thought to have arisen by neoteny, the Cladocera, is critically examined and found to be in need of reevaluation.
A Comparative Study of Primary Production and Related Factors in Four Saline Lakes in Victoria, Australia
Authors: Hammer U. Theodore
Published: February 2007

The purpose of the study was to compare the primary plankton productivities of lakes of different salinities and to determine the causative factors involved in their production rates. Four lakes (specific conductivity —mS cm−1 at 18°C) were initially chosen: Coragulac (9), Red Rock (25), Corangamite (38), Pink (250). Sampling and production measurements were made every two to three weeks.

Three lakes were dominated by specific phytoplankton blooms: Red Rock (Anabaena spiroides), Corangamite (Nodularia spumigena). Pink (Dunaliella salina). Coragulac Lake had more diverse populations.

Red Rock Tarn had some of the highest production values ever recorded. Extremely high soluble phosphate and inorganic carbon concentrations were the most important causative factors. Pink Lake had very low production rates. High salinity and low nutrient concentrations were limiting factors. The other lakes were intermediate in production and nutrient levels.

Zooplankton populations were also determined.
Influence of Temperature, Photoperiod and Trophic Conditions on the Seasonal Cycles of Phytoplankton and Zooplankton in Two Deep Subarctic Lakes of Northern Canada
Authors: Moore James W.
Published: February 2007

The densities of phytoplankton and zooplankton were determined for 12 consecutive months (1978–1979) in two deep oligotrophic lakes in northern Canada. The lakes were situated on the same river system, about 5 km from one another. While they exhibited similar temperature conditions, there were slight differences in the ionic content of the water. Overall, changing temperature was the most important factor influencing the duration of the growth cycles of phytoplankton and zooplankton. Nutrients generally controlled the intensity but not the timing of algal blooms. A similar relationship was recorded for the effects of food supply on the development of the major species of herbivorous zooplankton. Although changing photoperiod likely initiated the growth of several important algal and zooplankton species in the spring and early summer, light had no measurable impact on the development of planktonic communities throughout the remainder of the growing season. The higher ionic content of the water in one lake may have promoted the growth of protozoans during the fall and early winter.