bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of the Inshore Macrozoobenthic Community in Lake Naini Tal, U. P., India
Authors: Gupta P. K. , Pant M. C.
Published: February 2007

Certain 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

Glyphidrilus 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

The 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

The 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

Six 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

Phosphate‐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 image

Parameter 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

A 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

The 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

The 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

Data 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

The 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

The 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

We 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

The 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

In 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

Seasonal 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

Selenite 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.
Limnological Characteristics of Two Eutrophic and Four Mesotrophic Lakes in West‐central Florida
Authors: Dawes Clinton J. , Cowell Bruce C. , Gardiner William E. , Scheda Sandra M.
Published: February 2007

Limnological characteristics of six subtropical lakes were monitored to determine the factors which regulate chlorophyll α concentrations and phytoplankton standing crops. Most physical chemical variables showed non‐significant differences with depth but differences between lakes often were large. Phytoplankton blooms occurred throughout the year and there were marked differences between the hypereutrophic and mesotrophic lakes in chlorophyll α concentrations, standing stocks, and dominant species. Densities of total zooplankton and rotifers in the hypereutrophic lakes were 3‐ to 6‐fold greater than in the mesotrophic lakes. Regression models for chlorophyll α and total phytoplankton cell volume were calculated for each lake and for all lakes combined, but R2 values and numbers of shared variables tended to be low indicating the need for additional variables and more frequent sampling.
Eurycercus glacialis in Ireland (Cladocera, Chydoridae)
Authors: Duigan Catherine , Frey David G.
Published: February 2007

The taxon Eurycercus glacialis of Western Europe has been discovered living in the turloughs (tuar loch = dry lake) of Western Ireland. Only four populations were found during three field excursions, but because of the multitude of these waterbodies in the region, there must be many populations present. Turloughs are mainly periodic waterbodies occupying depressions in the drift overlying limestone. Most of them dry every year, and the bottoms are then used for grazing cattle. This periodicity prevents the establishment of fish populations, which would rapidly eliminate the cladoceran by size‐selective predation. Only one of the many populations known from Western Europe survives in the presence of fishes. A species of the glacialis group in Newfoundland (not yet described), which is the southernmost known location of E. glacialis sens. lat. in the world, occurs commonly with salmonid or gasterosteid fishes, but this is a completely different species. Scanning electron micrographs of E. glacialis and E. lamellatus in Western Europe will aid in understanding their morphological differences.
Influence of Seiche‐Generated Light Field Fluctuations on Phytoplankton Growth
Authors: Paul Lothar
Published: February 2007

Phytoplankton, owing to the periodic ascent and descent caused by internal seiches, is exposed to experiential fluctuations in light intensity. The increase in light intensity associated with its ascent towards the surface is greater than the decrease caused by its descent. A simple mathematical model is used to derive relationships showing that 1) the mean light intensity in an epilimnion influenced by internal waves is not more than 6.1% lower than in a stationary system and 2) in the meta‐ and hypolimnion of lakes of low transparency (i.e. with a high extinction coefficient) internal seiches of large amplitude increase the mean light intensity by several orders of magnitude. This can produce a many‐fold increase in the depth of the euphotic zone. The mean rates of photosynthesis of phytoplankton in the meta‐ and hypolimnion increase particularly at the antinodes of the waves. Internal seiches evidently may play an important role in causing plankton patchiness and in the presence of photosynthetically active phytoplankton at depths far below the 1% light limit.
Phytoplankton Analysis in Lake Sat Tal (U.P.), India
Authors: Pant M. C. , Joshi Archana
Published: February 2007

Species composition and periodicity of phytoplankton were studied in relation to various physico‐chemical parameters over a period of 18 months in the two basins of Lake Sat Tal. Taxonomic analysis led to 54 species. Phytoplankton density in the euphotic zone ranged from 0.33 × 105 to 4.12 × 105 cells I‐1 in the western basin (WB) and 1.31 × 105 to 6.05 × 105 cells I‐1 in the eastern basin (EB). The dinoflagellates (Peridinium willei, P. cinctum, Gymnodinium fuscum) which were relatively insignificant concerning number reached very high values concerning biomass, contributing 89 % and 92 %, respectively, to the total phytoplankton standing stock. Various factors as rainfall, light, temperature, organic matter, nutrients (particularly PO4‐P), silicate, were observed to play an important role in the periodicity of phytoplankton. Similarity coefficients revealed that the algal population was not very homogenous all the year round with similarities between consecutive samples ranging from 16 % to 77 % in WB and 21 % to 76 % in EB.
Feeding Ecology of the Allochthonous Feeder Rasbora daniconius (HAMILTON) (Cyprinidae – Teleostei)
Authors: Kumar K. Prem , John P. A.
Published: February 2007

Seasonal fluctuations in the dietary components of Rasbora daniconius inhabiting a perennial eutrophic pond have been studied on the basis of analyses of the gut contents over a period of one year from 1980 to 1981. Modified Points method was adopted for the quantitative estimation of the dietary items. Gut analysis revealed that the fish is predominantly an allochthonous feeder subsisting mainly on terrestrial Hymenoptera and Coleoptera. Flowers and seeds also formed part of the dietary composition of the fish. Allochthonous fauna were preferred at all the stages of the growth of the fish. Females have a greater preference for terrestrial Coleoptera and the males for Formicidae. The feeding intensities of three different length groups and both sexes were also ascertained. This revealed that June, July, October and November are the most intensive feeding periods of R. daniconius. Older and mature fishes were found to be more active feeders than juveniles.
Vergleichende Emergenzstudien an einem naturnahen und einem naturfernen Abschnitt des Fließgewässersystems der Fuhlenau in Schleswig‐Holstein
Authors: Böttger Klaus , Holm Uwe , Mikowski Karol
Published: February 2007

Comparison of Insect Emergence from Natural and Artificially Modified Sections of a Stream, the Fuhlenau, in Schleswig‐Holstein

There are no detailed reports in the literature concerning the relationships between the degree to which artificial conditions along a stream have replaced natural ones and the zoobenthos colonization. The ecological effects of mechanical disturbances from channelization, maintenance, or similar activities are given as causes of reductions in individual abundances and species diversity. The ecological effects are essentially more complex and should be determined separately for each of the individual taxa. The conclusions are based on emergences recorded in traps during a six month period from May to October.
Reaeration of Oxygen in Shallow, Macrophyte Rich Streams: I – Determination of the Reaeration Rate Coefficient
Authors: Thyssen Niels , Erlandsen Mogens , Jeppesen Erik , Ursin Christian
Published: February 2007

The rate coefficient K2 for the exchange of oxygen between flowing water and the atmosphere (reaeration) has been studied in six Danish streams covering a relatively wide range of hydraulic conditions, pollutional loading, and macrophyte abundance. 103 K2‐measurements were performed in 1978–85.

82 measurements were obtained applying 5 different indirect methods all balancing the sources and sinks of stream dissolved oxygen under conditions of normal operation of the system (3 methods) and under artificial depletion of the oxygen concentration of the stream water by addition of sodium sulphite (2 methods). 21 K2‐values were determined directly applying a gaseous tracer (krypton‐85) for reaeration.

Guidelines for selecting a proper method to determine K2 knowing macrophyte biomass and loading characteristics of the particular stream are provided.
Aquatic Ecosystem Characterizations by Biotic Indices
Authors: Guhl Walter
Published: February 2007

The suitability of various biotic parameters for the quality characterization of bodies of water was assessed with the aid of three real world examples which were furthermore characterized physically and chemically.

A number of biotic indices such as the Wright and Tidd index and the Chandler biotic score proved unsuitable since they take only parts of the biocenoses into account.

All diversity indices, e.g., the Simpson and the Shannon index, proved inadequate as well since elements essential for the description of a biocenosis are lacking.

The saprobity index proved fully useful and correct for the biological characterization of bodies of water. Similarity indices such as the Sørenson index may furnish valuable additional information.
The Influence of Crustacean Zooplankton on the Size Structure of Algal Biomass and Suspended and Settling Seston (Biomanipulation in Limnocorrals II)
Authors: Uehlinger U. , Bloesch J.
Published: February 2007

In a limnocorral (LC) experiment performed in mesotrophic Lake Lucerne, Switzerland, a control LC containing a planktonic community similar to that in the lake was compared with a LC where the large zooplankton had been removed by filtration at the beginning of the experiment. The herbivorous zooplankton (mainly Daphnia galeata and D. hyalina) reduced algal biomass and primary production, however did not influence the size structure of the phytoplankton and the relative amount of different size classes contributing to the total primary production. Likewise, the seston (POC and PP) concentrations were diminished without changes in particle size composition. Since herbivorous zooplankton transform smaller particles into larger particles (fecal aggregates) through their grazing activity and thus enhanced particle formation owing to coagulation and microbial activity, sedimentation losses of POC and PP were increased in the LC with zooplankton. The importance of planktonic and sestonic particle size structure in aquatic ecosystems is stressed, as the smallest algae (< 12 μm) contributed 80 % of the primary production, which is in contrast to the 33 % contributed to the total POC sedimentation by this particle size class.
Macrobenthic Distribution within the Sediment along an Estuarine Salinity Gradient
Authors: Dauer Daniel M. , Ewing R. Michael , Rodi Anthony J.
Published: February 2007

The distribution of the macrobenthic infaunal community within the upper 25 cm of the sediment was studied at 16 stations in the lower Chesapeake Bay. Stations were located from the tidal freshwater to the polyhaline zone of major tributaries (James, York and Rappahannock Rivers) and in the polyhaline portion of the lower bay mainstem. Profiles for total number of individuals, total ash‐free dry weight biomass and species encountered with depth were calculated. Except for the deep dwelling bivalve, Macoma balthica, tributary macrobenthic communities had a shallow depth distribution compared to the mainstem sites which were found in generally coarser sediments in the higher salinity region of the estuary.
Approche discriminante de contributions de différents échelons microplanctoniques aux mesures globales d'ETS dans des échantillons de mer. b. Bacteria
Authors: Romano Jean‐Claude , Laborde Pierre , Mimura Toru , de Souza‐Lima Yolanda
Published: February 2007

Discriminating approach of various microplanktonic‐stage contributions to whole electron transport system (ETS) measurements in sea‐water sampless. b. Bacateria

Data obtained from cultures of natural bacterial populations were applied to various water samples in order to determine both the phytoplanktonic and bacterial contributions to whole ETS water‐sample measurements. The bacterial part was estimated both by cell enumerations and HPLC muramic‐acid measurements and the phytoplankton contribution by enumeration and chlorophyll levels. An appropriate first‐order equation is adequate to low carbon content samples but must be corrested for highly organic loaded samples in order to obtain a better adjustment between the sum of the “estimated” phytoplanktonic and bacterial ETS and the really‐measured ETS concentrations in the water samples.
Oxygen Budget of a River Rich in Submerged Macrophytes (River Zschopau in the South of the GDR)
Authors: Müller J. , Weise G.
Published: February 2007

The oxygen budget of the river Zschopau, a flowing water typical of hilly areas in the south of the GDR, was investigated in regard of seasonal variations in the activity of submerged macrophytes. Oxygen concentrations were continuously measured in the river by means of electrodes. Seasonal activity patterns of Ranunculus penicillatus, the dominant macrophyte in the river stretch investigated, were found by laboratory experiments.

The oxygen budget was obtained by measuring CO2 concentrations by infrared gas analysis (IRGA) and CO2 and O2 concentriations by means of electrodes.
Growth of Tubifex tubifex Müller (Oligochaeta, Tubificidae) under Various Trophic Conditions
Authors: Finogenova N. P. , Lobasheva T. M.
Published: February 2007

Growth of Tubifex tubifex on highly caloric activated sludge and poor in organic matter natural silt was experimentally studied. The relationship between oxygen consumption rate, weight, and caloric value of T. tubifex body in culture on activated sludge was determined to calculate the growth efficiency (K2 = P/P + R). The growth rate has been determined, and models of T. tubifex growth are given under various trophic conditions conforming to results of the experiment. Somatic growth, generative growth and life span of this species were compared on the basis of the experiments and literature. Acceleration of growth and prolongation of life under conditions of caloric food and delay of these processes in silt poor in organic matter have been established and measured. T. tubifex was found to have advantages as compared to other tubificid species in response to increasing amounts of nutrient food in waters polluted by organic matter and, therefore, to produce abundant populations under these conditions.
Toxicity of an Anionic Detergent to the Spawn and Larvae of Anurans (Amphibia)
Authors: Plötner J. , Günther R.
Published: February 2007

Several experiments were performed to test the toxicity of FIT, a washing‐up and general cleaning liquid containing about 10 % sodiumalkanemonosulfonate (industrial name E 30) to spawn and larvae of anura. The LC50 values for spawn were between 1.62 × 10−3 % (Rana dalmatina) and 4.97 × 10−3 % (Rana temporaria). The sensitivity of anuran larvae depends on the concentration and duration of exposure to the detergent as well as on the developmental and differentiation stage of the organisms. The toxicity of FIT is not due solely to the alkanesulfonate it contains, but results from the joint action of the surfactant, polyphosphates and solvents.

The results indicate that detergents may be harmful to the amphibian fauna of Central Europe.
Schwankungen im Spektrum von Kriebelmückenarten und räumliche Konstanz der Eiablageplätze in einem Niederungsbach (Simuliidae, Diptera). Variation in Species Composition of Black Flies (Simuliidae, Diptera) and Spatial Stability of Oviposition Sites in a Lowland Stream
Authors: Rühm Walter , Prügel Manfred
Published: February 2007

The species composition of black flies (Simuliidae, Diptera) in a lowland stream of Aller‐Leineregion (northern Germany, FRG) is analysed in the course of several years. Normally, Odagmia ornata (MG.) is the dominating species. For a short sharply defined period Boophthora erythrocephala DE GEER appeared in a great number. Possible reasons and related research on spatial stability of oviposition sites are presented.
Seasonal Variations in some Physical and Chemical Properties of Water from an Undisturbed African Tropical Catchment Area (Guma Valley, Sierra Leone)
Authors: Mtada Obed S. M.
Published: February 2007

Four perennial streams in a completely forested area were investigated. The water cooled and warmed up during both the rainy and dry seasons. The chloride content of the water varied according to rainfall. Dissolved solids were relatively high (20 mgl−1) at the start of the rainy season due to leaching but they were diluted with increased volume of flow. Dissolved gases and BOD5 varied according to discharge and total suspended solids content. All the other chemical species likewise were subject to seasonal variations.
Interrelations between phytoplankton, submerged macrophytes, black swans (Cygnus atratus) and zooplankton in a shallow New Zealand lake
Authors: Mitchell S. F. , Hamilton D. P. , Macgibbon W. S. , Nayar P. K. B. , Reynolds R. N.
Published: February 2007

Different features of the limnology of Tomahawk Lagoon, a shallow, hypertrophic New Zealand lake were studied for varying periods between 1964 and 1986. Surveys in 10 years revealed a strong positive correlation between the winter black swan population and the biomass of macrophytes which in turn in a shorter study was inversely related to the abundance of phytoplankton. A regression model was developed relating the winter maximum swan population to phytoplankton productivity in the previous summer. The model worked well for another very shallow lake, but less well for a third lake with a mean depth greater than the feeding reach of swans.

No general mechanism could be established for suppression of phytoplankton when macrophytes were abundant, though the effect was large. Suppression of macrophytes in other years is attributed to shading by phytoplankton. The decline of one algal bloom was related to nitrogen deficiency followed by intense zooplankton grazing. Another was ended by the optical effects of a large flood‐borne silt inflow and flushing of phytoplankton. Empirical models relating chlorophyll a to phosphorus or nitrogen, and zooplankton biomass to chlorophyll a or phosphorus do not work well for this lake, and the general problems of modelling shallow highly eutrophic lakes are discussed.
Comments on the manna model
Authors: Walker I.
Published: February 2007

WANGERSKY and WANGERSKY'S (1980, 1981, 1983) Manna models on algal patchiness and competition are essentially stochastic models. Analysis of their phase‐spatial properties, however, reveals complementary, deterministic features: interspecific competition is relatively ineffective because of the high degree of compartmentalization of resource supply and consumption; the probability of consumption in a given place at a given time is largely independent of the rate of consumption in other places.
A Long Term Study of the Phosphorus Cycle in Lough Neagh, Northern Ireland
Authors: Gibson C. E. , Smith R. V. , Stewart D. A.
Published: February 2007

Eleven years of weekly observations on the phosphorus cycle in Lough Neagh are analysed. The data comprised inputs, outputs and lake concentrations of the soluble and particulate phosphorus fractions. It is shown that the particulate phosphorus input quickly sediments to the bottom and the particulate phosphorus in the lake is largely made up of phytoplankton. The average phosphorus retention in the lake was 34 %, similar to the particulate phosphorus input. Climate has a big influence on the phosphorus input and sediment release, both of which varied two‐fold. A simulation model suggested that suppression of sediment P release would reduce lake winter phosphorus concentrations by an average of 29 %.
The Significance of the Internal Nutrient Load to Hypertrophic Shallow Waters
Authors: Uhlmann Dietrich , Guyderitz Thomas
Published: February 2007

In two carp ponds with a long water residence time, the seasonal changes in concentration and internal mass‐flow of inorganic nutrients have been estimated together with oxygen production PN of phytoplankton and community respiration. The results were compared with the findings from laboratory microcosms (LM) with a high recycle rate between a) euphotic and b) aphotic + sediment compartment. In the LM's, a dark period of at least 12 hours was necessary for optimum remobilization of CO2, PO− and NH. Very high values of PN were measured even if external nutrient sources were missing. Low nutrient concentrations could be compensated by high vertical fluxes. A cycle of nocturnal mixing and of thermal stratification with anoxia at the mud water interface which increases nutrient regeneration seems to be the principal mechanism which maintains very high PN in hypertrophic shallow waters.
The Biogeography of Cladocera (Crustacea) in Tropical Australia
Authors: Timms B. V.
Published: February 2007

Ninetysix species of Cladocera, comprising 8 Sididae, 50 Chydoridae, 17 Macrothricidae, 5 Moinidae, 2 Bosminidae, and 14 Daphniidae, occur in tropical Australia. Of this number 38% are cosmopolitan including so‐called cosmopolitan species, 13.5% are circumtropical, 13.5% occur as well innear by countries, and 35% are endemic. North Queensland is a major area of speciation. Species richness varies from north to south and from wetter coastal areas to the drier inland. Major factors influencing richness and distribution are the relative proportion of floodplain billabongs in an area, coupled with rainfall reliability. The most common species include Alonella clathratula, Chydorus nr. pubsecens, Macrothrix triserialis, Oxyurella singalensis, Ephemeroporus nr. barroisi, Dadaya macrops, Diaphanosoma sarsi, Ceriodaphnia cornuta, and Dunhevedia crassa.
An Experimental Analysis of the Acid Sensitivity of the Common Planktonic Rotifer Keratella cochlearis
Authors: Havens Karl , Decosta John
Published: February 2007

An in situ mesocosm experiment was performed at neutral pH Lake O'Woods, West Virginia, to assess the impacts of acidification on the common planktonic rotifer Keratella cochlearis. This rotifer is typically replaced by K. taurocephala during the acidification of North American lakes. Despite a rapid pH reduction in this experiment (from 7.0 to 4.8 in 14 days), the abundance, mean body length and egg ratio of K. cochlearis did not decline in the acid treatment as compared to the untreated control. These results support the hypothesis that K. cochlearis is acid‐tolerant, and suggest that its disappearance from acid lakes is the result of biotic interactions within the plankton, rather than the result of toxic effects of altered water chemistry.
Chlorophyll Concentrations in Relation to Environmental Parameters in Different Situations in Shoal Lake (Manitoba‐Ontario)
Authors: Pip Eva
Published: February 2007

Seasonal and local chl a fluctuations were examined at two depth ranges in Shoal Lake, a productive Precambrian Shield system. Water residence time in the study area was short, without permanent summer stratification. Chl a fluctuations were significantly correlated with total molybdenum reactive phosphorus (MRP) and total inorganic nitrogen (TIN), but the types of relationships were different for the two nutrients. Chl a was also significantly positively correlated with total alkalinity and temperature, and inversely correlated with oxygen and light. MRP and dissolved organic matter appeared to be more important for near‐bottom chl than for surface chl. Principal component analysis identified 4 major dimensions in which the different locations could be compared in terms of seasonal chl a fluctuations.
Biological Assessment of the Water Quality in South‐Holland (The Netherlands)
Authors: Klapwijk Sjoerd P.
Published: February 2007

A hydrobiological study was carried out to elaborate the water quality classification system of CASPERS & KARBE (1966, 1967) for the larger stagnant bodies of water in the western part of the Netherlands. Significant correlations have been established between different physical and chemical parameters and phytoplankton community structures such as diversity and saprobity. From this a proposal is developed to quantify the water quality classes in CASPERS & KARBE'S scheme on parameters measuring the bioactivity, oxygen regime and phytoplankton community structure. The scheme is now incorporated in the practical water quality assessment in North‐ and South‐Holland both for routine monitoring as well as for special water quality studies.
Comparative Analysis of Feeding and Schooling Behaviour of the Cyprinidae Alburnus alburnus (L., 1758), Rutilus rutilus (L., 1758), and Scardinius erythrophthalmus (L., 1758) in a Backwater of the Danube near Vienna
Authors: Haberlehner Elisabeth
Published: February 2007

Underwater observations of the three common fish species Alburnus alburnus (L., 1758), Rutilus rutilus (L., 1758) and Scardinius erythrophthalmus (L., 1758) in a small part of the Danube flood area near Vienna have been made from June to October 1985 and 1986. Particular emphasis has been laid on the partitioning of feeding resources and habitat. It has been established that these species prefer different water zones. Alburnus a. and Scardinius e. are “obligate” schoolers (BREDER, 1967) whereas Rutilus r. is a facultative schooler. While feeding Rutilus r. and Scardinius e. form “aggregations” (BREDER, 1959) and both adopt equivalent feeding techniques. Furthermore Alburnus a. is a quick moving species living near the surface and chasing mostly in schools. While inter‐ and intraspecific aggression is rarely observed for Rutilus r. and Scardinius e., Alburnus a. often show interspecific actions.
The Effect of Food Quantity on Feeding and Metabolic Expenditure in Cladocera
Authors: Philippova Tamara G. , Postnov Andrey L.
Published: February 2007

The effect of Chlorella concentration on total metabolic expenditure, basal metabolism and filtering and ingestion rates was studied in juvenile and adult females of three cladoceran species. No significant influence of food concentration on basal metabolism was found, whereas total metabolic expenditure depended on Chlorella concentration. Total metabolic expenditure in cladocerans was subdivided into: basal metabolism and expenditure on filtration, locomotion and specific dynamic action (SDA). Significant positive correlations were observed between expenditure on filtration and filtering rate and between expenditures on SDA and ingestion rate.
Competitive Exclusion, Harem Behaviour and Host Specificity of the Water MiteUnionicola ypsilophora(Hydrachnellae, Acari) InhabitingAnodonta cygnea(Unionidae)
Authors: Davids Cornelis , Holtslag Johanna , Dimock Ronald V.
Published: February 2007

The co‐occurring freshwater musselsAnodonta cygneaandA. anatinaserve as hosts for the water mitesUnionicola ypsilophoraandU. intermedia, respectively. MaleU. ypsilophoradisplay a territorial behaviour. They fight with other males, and as a result, there is usually only one male per host. As a consequence, this intrasexual aggression results in female‐defence polygyny, or a harem mating system. In contrast,U. intermediashows no antagonistic behaviour between males.A. cygneacan serve as a host forU. intermedia, but this mite species apparently is excluded from the mussel byU. ypsilophora.In this way,U. intermediais restricted by competitive exclusion to the musselA. anatina.
Annual Cycles and Budget of Nutrients in Berre Lagoon (Mediterranean Sea, France)
Authors: Arfi Robert
Published: February 2007

The annual cycles of nutrients in the Etang de Berre were studied in 1985. From measurements twice a month at the input points, daily data for the freshwater flow and from daily measurements at the output point, an estimation is proposed for a nutrient budget. Seasonal variability is important, and a biological control of nutrient availability (locally remineralized products) results in a hydrologically controlled system (nutrients carried by continental waters) which produces the very high microalgal biomass observed in the lagoon. The seasonal halocline brings the euphotic layer very close to the remineralization site: nutrients are then constantly available to the phytoplankton.
Effets du cuivre sur l'ultrastructure de Scenedesmus quadricauda et Chlorella vulgaris. Effect of copper on the ultrastructure of Scenedesmus quadricauda and Chlorella vulgaris
Authors: Bastien Christian , Cǒté Raynald
Published: February 2007

A laboratory investigation was conducted to study the effect of various concentrations of copper on the freshwater algae Scenedesmus quadricauda and Chlorella vulgaris. Electron‐dense inclusions were observed in the vacuoles of S. quadricauda, and this alga showed some growth at a dose as high as 2,500 μg.1−1. The occurrence of the electron‐dense inclusions was correlated significantly with the copper concentration and seems to be implicated in the tolerance of the species. C. vulgaris was much more sensitive to copper than S. quadricauda and showed osmotic changes and membrane damage.
Temperature Tolerances and Geographic Distribution of Three Species of Caridina (Decapoda, Atyidae) in Sri Lanka
Authors: de Silva K. H. G. M.
Published: February 2007

The biokinetic zones of C. fernandoi, C. simoni and C. pristis were found to be 15–29 °C, 15–27 °C and 13–27 °C respectively, while their respective ranges of distribution were found to be in altitudes of 0–700, 0–700 and 450–850 m. Their responses to low temperatures indicate that all three species are unlikely to occur above 1,000 m. The lower limit of distribution of C. fernandoi and C. simoni extends to altitudes in which the temperature rises above their ultimate upper incipient lethal temperatures (UILT). They appear to avoid high temperatures by moving into cooler waters. C. pristis cannot do so since it lives in very shallow streams; the lower level of its distribution appears therefore to be limited by its UILT.
Phytoplankton Fluctuations during an Annual Cycle in the Coastal Lagoon of Cullera (Spain)
Authors: Rojo C. , Miracle M. R.
Published: February 2007

The seasonal variation and the vertical distribution of the phytoplanktonic population of the lagoon of Cullera, an elongated coastal lagoon with estuarine circulation of water, has been studied in three sampling stations: mouth, centre and source. Seasonal variation is determined by a marine‐freshwater interaction. In winter, the sea influence is important, a marine water wedge of anoxic water arrives at the sampling station located at the source and marine and brackish water species dominate the phytoplankton. Also marine species of zooplankton and fish enter the system, which may then be considered as exploited by the sea. In spring the marine wedge retreats from the source but remains in the centre and mouth, salinity diminishes, vertical mixing persists and phytoplankton is dominated by Cyclotella species. From late spring to autumn the freshwater influence prevails and a sharp stratification of the water is produced in the stations at the mouth and the centre, by means of a steep halocline coincident with an oxycline. The phytoplankton in this period follows a typical succession like those described in freshwater eutrophic lakes.

Vertical distribution of phytoplankton is determined by the presence of the oxycline, originated by the marine water wedge, whose depth varies seasonally but which is always present in the mouth and centre of the lagoon; only few species of algae can be found below its level.
Studies on the Effect of Cell Division‐inhibiting Herbicides on Unialgal and Mixed Algal Cultures
Authors: Ördög Vince , Kuivasniemi Kaija
Published: February 2007

The effect of two cell division inhibiting herbicides on unialgal and mixed algal cultures was studied in laboratory tests. The herbicides studied were trifluralin (analytical grade) and the active ingredient as well as the preparation (80 % a.i.) of diphenamid. The three green algal species used were Selenastrum capricornutum PRINTZ, Scenedesmus quadricauda (TURP.) BREB., Oocystis parva W. et G. S. WEST. The response of algae to herbicides was determined by cell counting, and measured by turbidity (750 nm) and the 02‐production of some of the treated cultures.

The EC50‐value (96 h) of trifluralin to Selenastrum capricornutum was 3.3 mg/l. There were differences in the sensitivity of the three algal strains to the diphenamid; the EC50‐values to Selenastrum, Scenedesmus and Oocystis were 16.7, 10.1 and 6.3 mg/l, respectively. The lag phase observed in the growth of the treated cultures caused by diphenamid was verified by O2‐measurements. The preparation of diphenamid was not as effective as the active ingredient. In mixed cultures the ratio between two different algal strains depended both on the concentration of the diphenamid and the sensitivity of the two strains.
Herbivores and the Spatial Distributions of the Phytoplankton. II. Estimating Grazing in Planktonic Environments
Authors: Wirick Creighton D.
Published: February 2007

Large errors are made when laboratory measurements of the ingestion rate of herbivorous zoo‐plankton are used to estimate grazing in planktonic environments. The errors arise because the spatial heterogeneity in natural plankton distributions is greater than the heterogeneity present in laboratory experiments. Two probability models are developed for extrapolating laboratory measurements of ingestion to planktonic environments. Both models require sample statistics of the plankton distributions, and these are estimated from sampling studies of the small scale distribution of marine plankton. One model predicts laboratory measurements overestimate the ration obtained by an individual copepod by 30 %. A second model predicts errors exceeding ±50 % are possible when laboratory measurements are used to estimate the grazing by a population of cope‐pods.