bluuebunny/crossref_metadata_2025 huggingface dataset:
A Comparison of the Zooplankton in Two Newfoundland Bays with Differing Influences from Major Currents
Authors: Davis Charles C.
Published: February 2007

Quantitative zooplankton samples were obtained at four regular stations and one irregular station in Placentia Bay, Newfoundland between mid June 1974 and mid May 1976. Sampling was attempted fortnightly as regularly as weather conditions and competition from other ship users would allow. The results are compared with those obtained and previously published in a similar study from Conception Bay, Newfoundland in 1977 to 1978. There was a greater diversity of species in Placentia Bay, and for most species the numbers/m3 were greater. The two bays are influenced by somewhat different current systems, and climatic conditions are a little milder and foggier in Placentia Bay. The same species were common in both bays, with copepods usually being the most important.

Among copepods, two of the most important species namely Pseudocalanus sp. and Oithona similis were less abundant in Placentia Bay, but this was offset by a greater abundance of Temora longicornis.

A few of the problems that require further investigation are outlined.
Estimation des paramètres fondamentaux de la dynamique d'un estuaire à marées. On the Dynamics of a Tidal Estuary: Estimation of the Principal Factors
Authors: Douvillé Jean‐Luc , Riaux Catherine
Published: February 2007

In order to obtain a better understanding on the relationship between salt and fresh‐water masses in an estuary on the Northern Brittany coast, a study on the tidal dynamics has been carried out. A simple model for the calculation of the mean current velocities is proposed taking into account the estuarine topography, tidal parameters and river discharge. The model also estimates the Richardson, Froude and Reynolds estuarine numbers. These can be used in further studies on the particle transport in this estuary.
Field and Laboratory Studies on Nile Phytoplankton in Egypt. II. Phytoplankton
Authors: Ahmed Ahmed M. , Mohammed Ahmed A. , Heikal Medhat M. , Zidan Mohammed A.
Published: February 2007

Variations in chlorophyll a concentration and in qualitative and quantitative counts of Nile phytoplankton were followed at Assiut from September 1980 to September 1982. Chlorophyll a concentrations usually correlated well with phytoplankton density. The total phytoplankton exhibited higher counts in spring and summer than in autumn and winter. While diatoms exhibited the highest counts, green algae contributed more genera to the phytoplankton community.
Influence de quelques paramètres du milieu d'incubation sur la survie d'alevins de saumon atlantique, Salmo salar L., en ruisseau expérimental. Influence of some Environmental Parameters upon Survival during Embryonic Development of Atlantic salmon, Salmo solar L., in an Experimental Stream Channel
Authors: Marty Claude , Beall Edward , Parot Giles
Published: February 2007

The effect of some environmental parameters of the redd (substrate composition, interstitial dissolved oxygen concentration) upon survival of Atlantic salmon embryos was studied in a large artificial stream channel. Batches of 3000 eyed eggs were buried 0.25 m deep in the gravel substrate of 8 different channel sections, where natural or artificial sediment deposition took place. Upon emergence, fry were captured in drift nets or by electrofishing. Survival varied from 32 to 94 % in the different sections. It was strongly affected by volume of sediment less than 10 mm in particle size and more particularly by the fraction less than 0.2 mm, the main component of natural sediment deposition. Survival was less strongly determined by oxygen concentration variations except for values less than 2 mg/l obtained in the section with highest sediment deposition. Available volume of interstitial void space appeared to be crucial for good survival during larval development.
Bacterial Activity in a Reservoir Determined by Autoradiography and its Relationships to Phyto‐ and Zooplankton
Authors: Šimek Karel
Published: February 2007

In the drinking water reservoir Římov (Southern Bohemia) bacterioplankton was studied during 1983. Special attention was given to the relationships between parameters of bacterial abundance, total and individual activity. Bacterial counts and biomass was assessed and autoradiographic determinations of the proportion of active bacteria incorporating thymidine (Th) and mixture of amino acids (AA) and total uptake rate of AA were made over a year in the surface layer and during summer stratification from the thermocline and 15 m depth. Specific activity of metabolically active bacteria (SAMAB) and specific activity per unit of biomass (SAUB) were negatively correlated with counts of metabolizing cells and with bacterial biomass, respectively. Total and individual heterotrophic activity and counts of bacteria coincided with the changes of phytoplankton biomass, whereas bacteria incorporating Th were more tightly correlated with primary production. The most significant relation of metabolically active bacteria was found to cladoceran biomass. Thus, this part of heterotrophic bacterial activity seems to be stimulated by leakage of dissolved organic matter from phytoplankton being disrupted and incompletely digested by cladocerans rather than from healthy photosynthetizing cells.
Investigation into Seasonal Growth of Branchiostoma lanceolatum off Heligoland, According to Data by Courtney (1975)
Authors: Sager Günther , Gosselck Fritz
Published: February 2007

Values of length growth of Branchiostoma lanceolatum off Heligoland were gained in 1962–63 by COURTNEY (1975a, b) over six age groups comprising about 800 individuals. Growth, generally was found to stop when sea water temperatures fell below 10 °C. Stagnation for at least six months could be observed as a result. COURTNEY gave a graph for length development in consecutive age groups by connecting clusters of points by straight lines, for lack of more adequate methods not available at that time.

In a review, tests are recalled for the mathematical representation of growth with seasonal variations. Initial work was done by URSIN (1963), followed by CLOERN and NICHOLS (1978). These authors tried to introduce temperature to the PÜTTER/BERTALANFFY function of length growth, in a direct or indirect way. SAGER (1982) extended this idea regardless of the growth function proper. In a first step, the modification holds for seasonally restricted growth just down to momentary stagnation (SAGER, 1983a, b). The second step (SAGER, 1984a) allows for stagnation over several months and is suitable for approximation of the COURTNEY values, which is performed by nonlinear regression.

Results show fully satisfying coincidence, as manifested in numerical and graphical displays. Moreover, the growth rate or growth velocity has been calculated and is plotted graphically. Complete description of growth development, according to the COURTNEY samples, has been achieved by a function with only five parameters.
Modifications of the Ekman Sampler
Authors: Håkanson Lars
Published: February 2007

Many types of sediment samplers have been designed for specific purposes and for sampling in different aquatic environments. The objective of this technical note has been to introduce two specific improvements of the traditional Ekman grab sampler, which is a well‐known apparatus for sampling of soft sediments, especially in bottom faunistic contexts. The two new modifications concern the automatic closing mechanism. The jointed quadrant and the jointed, hooked axis, both made of brass, provide a much handier and more reliable operation than, e.g., the traditional automatic mechanism.
Community Metabolism in Tropical Undrainable Rural Fish Ponds
Authors: Oláh J. , Sinha V. R. P. , Ayyappan S. , Purushothaman C. S. , Radheyshayam S.
Published: February 2007

The process of community metabolism including primary production and community respiration in eighteen undrainable rural fish ponds in India was quantified using the diurnal oxygen curve method. A considerable portion of the gross primary production that was in the moderate ranges, was consumed for the community respiration. Negative, and low positive values of net primary production indicated the significance of the allochthonous supply in these organic enriched systems. The low values of sediment respiration signified the reduced condition of stagnating sediment acting as energy trap.
Evolution de la composition en acides gras d'un phytoplancton lacustre (Lac Pavin, France)
Authors: Bourdier Gilles , Amblard Christian
Published: February 2007

Fatty Acid Composition of Lacustrian Phytoplankton (Pavin Lake, France)

Fatty acid composition of lacustrian phytoplankton was established during a study carried out on Lake Pavin (France) from May to September 1981.

Fatty acid spectra point out even numbers of carbon atoms (ranging from 14 to 22) and in particular unsaturated fatty acids preponderance. In addition, the occurrence of some unsaturated fatty acids is directly linked to phytoplankton taxonomic composition, but also to physiological state of the cells. Lastly, the main types of phytoplankton populations differ in the degree of unsaturation of their total fatty acids.
Relationship between Number of Eggs, Brood Weight, and Female Body Weight in Crustacea
Authors: Ivanova Marina B. , Vassilenko Stella V.
Published: February 2007

Relationships between number of eggs (Ng), brood weight (Wg), and body length (L) and weight (W) of females were studied for 16 orders and suborders of Crustacea. The study was based on the authors' observations in the inland waters of the European USSR, in the coastal regions of the fareastern and northern seas and data from V. V. KUZNETSOV (preserved in archives). An extensive literature was also used. The equations describing the relationships (Ng=f(L) and Wg=f(W) are calculated for some species and high taxons. On the average for the superclass (excluding the order Notostraca) the Wg/W ratio appeared to be 0.16. This ratio is markedly different for species of Notostraca. It is supposed that this difference is due to the high metabolic rate of Notostraca.
Germination and Growth of Potamogeton pectinatus (L.) at Different Water Depths in Lake Nainital, Uttar Pradesh, India
Authors: Purohit Rekha , Singh S. P.
Published: February 2007

Data on germination of tubers and subsequent growth of young plants of Potamogeton pectinatus were recorded at different depths of the water column in Lake Nainital. The depth of euphotic zone is about 5 m. Tubers were placed at 1, 2.5, 5.0, 7.5 and 10 m water depth in brass net bags. A highly significant negative correlation was found between depth on one hand and germination percentage of tubers, length of shoots and number of leaves on the other hand. Germination of tubers was positively related to pH, dissolved oxygen and temperature of water.
Sediment Oxygen Consumption in Tropical Undrainable Fish Ponds
Authors: Oláh J. , Sinha V. R. P. , Ayyappan S. , Purushothaman C. S. , Radheyshyam S.
Published: February 2007

The magnitudes of sediment oxygen consumption in the rural undrainable fish ponds of Orissa, India, were quantified and partitioned into bacterial, animal and chemical uptakes. It was in the low range, comprising a maximum of 30 % of the total community respiration. Chemical uptake was generally predominant, followed by bacterial respiration and low macroinvertebrate respiration. Evidence has been produced to the limiting effects of oxygen levels, mechanical disturbances and bioturbation on uptake rates in these ponds. The sediment layers are shown to act as energy traps, and measures are suggested for improved sediment ‐water interaction and enhanced nutrient recycling.
Approche discriminante de la contribution de différents échelons microplanctoniques aux mesures globales d'ETS dans des échantillons d'eau de mer. a. Phytoplancton
Authors: Romano Jean‐Claude , Mimura Toru , de Souza‐Lima Yolanda
Published: February 2007

Discriminating Approach of Various Microplanktonic‐stage Contributions to Whole ETS Measurements in Sea‐water Samples. a. Phytoplankton

Data obtained from algal cell cultures were applied to various sea water samples in order to estimate the specific contribution of phytoplanktonic organisms to whole ETS (electron transport system) measurements of these samples which have been collected at eleven stations in the northwest Mediterranean Sea. When the phytoplankton ETS contributions were quantified by cell enumerations or by other indirect‐biomass‐indicator measurements, the results are in good accordance to the recorded ETS measurement values of the sample. More specific of the phytoplankton stage is the index used for such an estimation (as chlorophyll a), and better is the relationship between both estimated and measured ETS values.
Malathion Toxicity: Effect on the Ovary of the Zebra Fish Brachydanio rerio (Cyprinidae)
Authors: Ansari Badre Alam , Kumar Kaushal
Published: February 2007

The nucleic acids (DNA and RNA), protein contents and the activity of alkaline phosphatase was significantly decreased in the ovary of Brachydanio rerio after exposure to different concentrations of malathion, an organophosphorus pesticide. Total free amino acids and acid phosphatase activity, however, were enhanced. The decrease in the measured parameters depended on both concentration and time. Histopathological studies revealed developmental arrest at all levels from oogonium to tertiary stage oocytes. After transfer to fresh water without the pesticide, there was a marked trend of recovery in al' the parameters studied.
Secondary Production and Energy Transfer in the Polluted River Saale (Thuringia, Southern GDR)
Authors: Schönborn Wilfried
Published: February 2007

In the middle reaches of the Saale (α‐mesosaprobic region) there are two final consumers: Erpobdella octoculata (leech) and fish. Three main flows of energy in the river ecosystem are described and quantified. The food web is only poorly developed. In the River Saale Erpobdella is the main predator and controls most of the meio‐ and macrozoobenthos. The type of energy transfer described here seems to predominate in polluted rivers. A qualitatively different type of energy transfer predominates in clean running waters. The relationships between energy transfer and self‐purification are discussed.
A Guide to the Study and Identification of Fossil Testate Amoebae in Quaternary Lake Sediments
Authors: Ellison Robert L. , Ogden Colin G.
Published: February 2007

Fossil shells of testate amoebae, commonly found in Quaternary sediments, provide another key for the interpretation of the recent history of lakes. Outline drawings and details of shell composition provide the micropalaeontologist with a practical guide to the taxonomy of these organisms.
Relationship between Zooplankton Development and Environmental Conditions in Different Types of Lakes in the Zone of Temperate Climate
Authors: Ivanova Marina B.
Published: February 2007

Comparison of the number of species and biomass of planktonic crustaceans with morphometric, hydrological, and hydrochemical features of lakes in the zone of temperate climate shows that there are no functional correlations between the development of zooplankton and each of the other separate factors. Results of multiple regression analysis for description of relationships between biotic and abiotic conditions were unsatisfactory (R2⩽0.7) for the greater part of studies. It is apparently necessary to find methods to examine environmental characteristics limiting biological productivity in lakes and to classify lakes on this basis. Such classification may allow to work out quantitative predictions of plankton and benthos biomass development in response to change of some environmental factors.
A Study of Diaphanosoma Species (Crustacea: Cladocera) of the “Mongolianum” Group
Authors: Korovchinsky N. M.
Published: February 2007

Material from 49 localities in Europe, Asia and Africa is used to study two similar Diaphanosoma species, viz. D. mongolianum UENO, 1938, and D. lacustris KORINEK, 1981, both of which were described earlier under other names, the most common of which were “D. brachyurum”, “D. leuchtenbergianum” and “D. birgei lacustris”. These species are redescribed in detail, consideration being given to interpopulational and individual morphological variability, the type material, and material from type localities. The morphology of the setae of the swimming antennae is studied in detail, and the author concludes that some of them are not only used for swimming but also perform a sensory function. Some aspects of the biology of the species are described. They inhabit water bodies of different types, are often so abundant that they constitute the main component of zooplankton communities, and are an important link in the trophic chain. Little known cases of the co‐occurrence of Diaphanosoma species in a water body are described. Localities known for D. mongolianum and D. lacustris are situated mainly in the temperate and subtropical zones, the former species penetrating farther north than the latter. However, they are also found in the White Nile (Sudan) and Ethiopian lakes. This southward penetration may be connected with the azonal distribution of fluviatile fauna and with the altitude of Ethiopian lakes.
Niche Extension of Aquatic Macrophytes in Hydrolakes: Predictive Assessment of Environmental Impacts
Authors: Rørslett Bjørn
Published: February 2007

A statistical model for the survival (potential) niche size of submerged macrophytes is related to fluctuating water levels. Designated as the spatial survival niche model (SSN), this model describes the potential niche by means of a product of spatio‐temporal mortality functions. The SSN model enables quantitative estimates of the niche's width, central location, and percentile points.

The model is corroborated by an extensive Isoëtes lacustris L. data set from 17 Norwegian lakes, which included hydro‐electric lakes (hydrolakes) as well as non‐impacted lakes. The close fit between model prediction and the macrophyte's actual spatial performance is remarkable and encouraging from an impact assessment point of view.
Latitudinal Variations in Body Size and Species Diversity in Marine Decapod Crustaceans of the Continental Shelf
Authors: Steele D. H.
Published: February 2007

The number of species of caridean, brachyuran and anomuran decapods increases from high to low latitudes in both hemispheres. This is shown to be due mainly to changes in the abundance of small species. Possible explanations for these variations in abundance are discussed. The other infraorders of decapods are confined to mid and low latitudes.
Detritus and Epibiota on Artificial Substrata: The Possible Role of Food in Structuring Hawaiian Epiphytal Amphipod Communities
Authors: Russo Anthony R.
Published: February 2007

Epiphytal amphipods prefer artificial substrata (bottle brushes) which accumulated epibiotic coatings while submerged in the sea for a period of up to 15 days. There is evidence that these amphipods eat epibiota on algae (predominately Padina japonica YAMADEA 1931 and Dictyota crenulata AGARDH 1847) and that food availability may be a factor which helps structure epiphytal amphipod communities.
Seasonal and Spatial Overlap between Cladocerans in Humic Lakes
Authors: Hessen Dag Olav , Schartau Ann Kristin
Published: February 2007

Seasonal and vertical distribution, migratory patterns and reproductive effort in coexisting cladocerans were investigated in three humic lakes with different, but low phytoplankton abundances and varying fish predation pressure. Seasonal and vertical habitat or niche overlap varied, but were high within most pairs of species in all localities. Migration was conspicuous in presence of planktivorous fish, less so in the fish free lake. Despite algal densities below incipient limiting level (30–200 μg C I−1) and a low ratio (3–10) of algal to cladoceran biomass, zooplankton distribution and reproductive parameters were not clearly related to algal biomass.

Bacterial biomass equalled 10–50% of phytoplankton biomass, while detritus by far was the largest of the particulate compartements. It was concluded that with a possible exception of the early summer algal bloom, additional carbon sources (bacteria, detritus) are important to cladoceran nutrition in these humic lakes. A large share of N‐ and P‐poor detritus in the diet would give zooplankton productivity limitation by food quality in terms of elemental composition rather than food quantity. This would permit coexistence even of species with rather high food overlap, but give low production rates for all species in agreement with the observations.
A Physical, Chemical and Biological Characterization of the Ushant Tidal Front
Authors:   Group “Grepma”
Published: February 2007

A multidiscriplinary study was carried out during the summer of 1982 in the area of the Ushant tidal front at the entrance of the English Channel. The stratified water masses (West of the front) and the mixed water masses (East of it) are characterized with respect to their main physical, chemical and biological properties and a comparative budget of organic carbon is presented. Several physiological, biochemical or taxonomical indices of phytoplankton and zooplankton populations are investigated. The effects of the tidal regime on space‐time variability and nutrient enrichment are emphasized.
Atlantic Salmon (Salmo salar) Smolt Production in a Newfoundland River System Characterized by Lacustrine Habitat
Authors: O'connell Michael F. , Ash Evan G. M.
Published: February 2007

In insular Newfoundland, wild anadromous juvenile Atlantic salmon make extensive use of lacustrine habitat for rearing. Smolt production was determined for a portion of a river system where virtually all rearing habitat is lacustrine. Production in terms of lacustrine habitat was estimated to be 10.1 smolts‐ ha−1. Smolt production is discussed in relation to morphometric characteristics. A comparison is made with smolt production obtained from stockings of swim‐up fry directly into lakes in another insular Newfoundland river system.
Spatial Distribution of the Nematode Fauna and Production of Three Nematodes (Tobrilus gracilis, Monhystera stagnalis, Ethmolaimus pratensis) in the Profundal of Piburger See (Austria, 913 m a.s.l)
Authors: Pehofer Harald E.
Published: February 2007

The species composition and the spatial distribution of the nematode fauna of Piburger See is discussed briefly. The study then concentrates on the three species (Tobrilus gracilis, Monhystera stagnalis, Ethmolaimus pratensis) which form the lake's profundal nematode fauna between depths of roughly 8 and 13 meters. This profundal fauna is separated by a distinct metalimnetic abundance minimum from the very diverse littoral community. In addition to taxonomic and ecological considerations, the zonation of the three species within their main habitat is described, and life cycles cohort production as well as annual production are evaluated from the field data. Total annual nematode production within the profundal habitat (8–13 m) in Piburger See amounts to 11.6 kg per hectare. 65 % of which are contributed by T. gracilis, 22 % by M. stagnalis and 13 % by E. pratensis. For the whole area under observation (6 to 13.5 m, including the scarcely populated border zones) mean annual nematode production is 7 kg per hectare.
Variations temporelles de l'ultrastructure de Scenedesmus quadricauda exposée au cuivre lors d'une expérience à long terme
Authors: Bastien Christian , Cǒté Raynald
Published: February 2007

An experiment was conducted with a continuous culture of Scenedesmus quadricauda for 50 days in a copper concentration of 250 μg l−1. Ultrastructural examinations were carried out at different times to obtain the sequence of events. After 1.5 h of exposure, the ultrastructural effects were obvious: the chloroplasts were retracted and all cell structures appeared diffuse. The same observations were reported after 3, 6, 12 and 24 hours. Between the 3rd and 15th days of the experiment, the cells showed major accumulations of starch, lipid and electron‐dense inclusions in the vacuoles, and the cell walls became thicker. After 22,32 and 50 days the cells appeared normal, but the cytoplasm was densely packed with ribosomes and the endoplasmic reticulum was evident in most cells. However, atomic absorption analysis for copper showed that there was no bio‐accumulation after 50 days of exposure. These findings suggest the implication of a second tolerance mechanism to copper (possibly extracellular complexation or removal) that is activated after long exposure, in contrast to electron‐dense inclusions, which appear after a relatively short time (2 days).
The Life History and Occurrence of Sialis lutaria L. (Megaloptera) in the Littoral Zone of Lake Esrom, Denmark
Authors: Dall Peter C.
Published: February 2007

The life history and distribution of Sialis lutaria L. in the exposed littoral zone of Lake Esrom, Denmark were examined during 1979/80. Sialis showed an annual life cycle with mean annual abundance of 20 and 40 ind m−2 at 0.4 and 2.0 m depth, respectively. Growth peaked during July with rates of about 10 % d−1. Net annual production averaged 0.2 g DW at 0.4 m depth and 0.8 g DW at 2.0 m depth. The annual P/B‐ratios were estimated in the range of 4.6‐7.1.
Field and Laboratory Studies on Nile Phytoplankton in Egypt IV. Phytoplankton of Aswan High Dam Lake (Lake Nasser)
Authors: Mohammed Ahmed A. , Ahmed Ahmed M. , El‐Otify Ahmed M.
Published: February 2007

Seasonal, local and monthly vertical variations in chlorophyll a concentration and in qualitative and quantitative counts in Aswan High Dam Lake (AHDL) phytoplankton were followed from March 1982 to February 1984. The chlorophyll a values correlated more or less with the total phytoplankton counts. Total algal counts exhibited considerable local variations in the different seasons and tended to decrease in the most southern part of AHDL, especially during the flood period. The temporal course of algal development showed an almost inverse trend to that of dissolved nitrate‐nitrogen. The possibility of nitrogen limitation of algal growth was verified.

Diatoms and blue‐green algae alternated in the dominance of the phytoplankton community. The genera Cyclotella and Anabaenopsis respectively were the most predominant genera among the diatoms and blue‐greens and consequently in the phytoplankton community.
Phosphorfällung über Calciumcarbonat im eutrophen Wallersee (Salzburger Alpenvorland, Österreich). Coprecipitation of Phosphorus with Calcite in the Eutrophic Wallersee (Alpine Foreland of Salzburg, Austria)
Authors: Jäger Paul , Röhrs Jürgen
Published: February 2007

By chemical analyses at the eutrophic Wallersee (Austria) a considerable precipitation of calcite during autumn overturn was found. It is a pure anorganic calcite precipitation, caused by the loss of free carbonic acid to the atmosphere during the mixing of epilimnic and hypolimnic water.

An essential coprecipitation of phosphorus with the anorganic calcite precipitation could be shown by calcium and phosphorus balances and by SEM investigations.

During the epilimnic biogenic calcite precipitation (in summer) phosphorus coprecipitation makes 0.19% of the calcium fallout. Phosphorus coprecipitation increases up to 0.42 % during the anorganic calcite precipitation when autumn overturn takes place. With respect to the total phosphorus sedimentation in the lake 25 % are coprecipitated with calcite.
The Importance of Higher Trophic Level in the Process of Eutrophication in Enclosure
Authors: Tátrai István , Tóth László G. , Istvánovics Vera , Zlinszky János
Published: February 2007

Enclosures open to the sediments and the atmosphere were used to elucidate the response of algae and bacteria to the nutrient enrichment from fish in the mesotrophic area of Lake Balaton. Active transformation between the forms of nitrogen was observed especially in the enclosure with fish. Both nitrogen and phosphorus values were influenced by fish. Changes in nutrient dynamics, composition and biomass of algae and bacterial production were measured. It has been shown that benthivorous fish with a biomass illustrative of the most eutrophic part of the lake were able to generate high bacterial production rate and a strong outburst of blue‐greens.
Production de CO2 à l'interface air‐mer. Une approche par l'étude des phénomènes respiratoires dans la microcouche de surface. CO2 Production at the Sea‐Air Interface. An Approach by the Study of Respiratory Processes in Surface Microlayer
Authors: Garabétian Frédéric
Published: February 2007

Sea‐surface microlayer and underlaying water samples were collected in the Bay of Marseilles (France) in order to study respiratory activity of microneuston and its possible influence on respiratory CO2 production.

Three methods were tested: Biochemical Oxygen Demand (BOD) as an estimation of community respiration, Electron Transport System activity (ETS) and 14C‐Glucose uptake monitored by 14C‐CO2 liberation.

BOD and ETS data clearly showed enhanced respiratory activities (up to 310 μl O2/l/h) in surface‐films as compared to underlaying waters; moreover the slope of the linear regression between these data led to R/ETS value of 0.689 and provides evidence for the presence of an important heterotrophic fraction within the microneuston.

Though 14C‐Glucose measurements showed only a slight trend for higher total activity (incorporation + respiration) in surface microlayers, significant enhancement of relative 14C‐CO2 production giving rise to CO2 diffusion across air‐water interface was observed.
The Processing of Leaves of Trees and Aquatic Macrophytes in the Network of the River Rhone
Authors: Chergui Hassan , Pattee Eric
Published: February 2007

Breakdown rate of terrestrial and aquatic leaves was found to depend on leaf species and on the biotope considered.

As the leaves started decaying at different dates and had different breakdown rates, consumable allochthonous or autochthonous organic matter was fed to the aquatic system throughout the year, from one summer to the next.

A comparison with former results on the main channel confirms the existence of a transversal gradient in the fluvial network: under the influence of fungal and invertebrate colonization, breakdown was fastest in the channel of the river, slower in an open side‐arm, and slower still in a more lateral and closed side arm, in which organic matter accumulated in hypoxic conditions.
Downstream Changes in Caddisfly Composition and Abundance in Relation to Changes in Water Conductivity and Oxygen in the River Butron Basin
Authors: Basaguren A. , Orive E.
Published: February 2007

This paper deals with the abundance and distribution of caddisfly larvae in the River Butron basin. Spatio‐temporal changes in caddisfly community structure, detected by means of correspondence analysis, are related to physico‐chemical changes, mainly conductivity and oxygen.
Distribution and Seasonal Abundance of Benthic Macroinvertebrates in Lake Naini Tal, U.P., India
Authors: Gupta P. K. , Pant M. C.
Published: February 2007

A total of thirty taxa of benthic macroinvertebrates were collected from Lake Naini Tal (area = 48 ha, mean depth = 16.2 m) situated 1937 m above sea‐level in the Kumaun Region of the Himalaya. Of these, Chironomus plumosus and Tubifex tubifex were numerically dominant, while Viviparus bengalensis (Mollusca) was the most abundant species in terms of biomass. The seasonality was characterised by two peaks (May and December) both in density and biomass. The population density as well as biomass declined with progressive water depth up to 7 m. Beyond 7 m water depth not even a single individual was found.
Possible food chain relationships between bacterioplankton, protozoans, and cladocerans in a reservoir
Authors: Šimek Karel , Macek Miroslav , Seďa Jaromir , Vyhnálek Vojtêch
Published: February 2007

Ingestion of fluorescent particles by natural protozoan assemblage was studied in the Řimov Reservoir (Southern Bohemia) from April to October, 1987. Attached and free‐living bacterial abundance, proportion of active bacteria, density of suspended particles and biomass of cladocerans were also monitored.

Heterotrophic nanoflagellates (HNF; 5–12.8 102ml−1) were the dominant bacterial micrograzers during the spring period and consumed 3 to 9% of the total bacteria per day. After the spring phytoplankton bloom maximum densities of suspended particles and attached bacteria (up to 28% of the total counts) were found. Development of cladocerans in May sharply decreased the proportion of attached bacteria and kept them below 5% of the total counts.

All the studied components of plankton except Cladocera decreased during the clearwater phase. The most significant drop was observed in the numbers of protozoans, and they were negligible for bacterial elimination. Bacterial losses during that time apparently were due to cladoceran grazing.

During the summer period, ciliates (15–142 ml−1) were mostly dominant micrograzers, and protozoan community grazing increased up to 21% of bacterial standing stock per day. The proportion of active bacteria was strongly correlated with protozoan grazing (r=0.83).
Protozoans—the first food of larval herring (Clupea harengus L.)?
Authors: Spittler P. , Brenning U. , Arlt G.
Published: February 2007

In short‐run experiments herring larvae at the end of the yolk sac stage (SL 6.5 to 8.5 m) were fed with maize and potato starch to investigate the effect of particle size on food selection. About 20% of the larvae ingested these particles during the experiments.

In the case of maize starch (3 to 26 μm grain size) the size classes from 14 to 25 μm and in the case of potato starch (5 to 80 μm) the size classes larger than 29 μm were preferred. The highest numbers of ingested grains per larva were 150 maize starch grains and 57 potato starch grains.

The selective uptake of these size classes leads to the conclusion that planktonic organisms in this size range—in other words mostly protozoans—may play an important role as a first food source of herring larvae.
Evolutionary morphological development of the cladocera of the superfamily sidoidea and life strategies of crustaceans of continental waters
Authors: Korovchinsky Nikolay M.
Published: February 2007

Comparative‐morphological analysis of the structure of the Cladocera of the superfamily Sidoidea ( = Ctenopoda) comprising the families Sididae and Holopediidae, compared with representatives of other groups: Chydoroidea (=Anomopoda), Limnadiiformii (= Conchostraca), Polyphemiformii (Polyphemiformes (= Onychopoda) and Leptodoriformes (= Haplopoda)) and Branchipodiones (Branchipodiformes (= Anostraca) and Triopiformes (= Notostraca)) is made. The main parameters and structures important in functional‐morphological and ecological aspects are considered: including dimensions of the body, its form and proportions, the complex eye, swimming antennae, body covers, thoracic limbs, the postabdomen. In distinction from all crustaceans under consideration in the Sididae and the Polyphemiformii organs contributing to rapid manoeuvrable swimming, soaring and good orientation in the environment received the prevailing development in evolution: antennae, stabilizing appendages of the posterior part of the body, the eye, etc. All this predetermined elaboration of the life strategy in these forms mainly aimed, especially in the Sididae, at active avoidance of predation combined with elements of passive protection (imperceptibility attained by various methods). Representatives of the Sididae, including planktonic Diaphanosoma, well survive in water bodies with the intensive press of predation. All others, including the Holopediidae, clearly possess the passive protection (development in localities inaccessible to predators, imperceptibility, protective structures on the body surface, etc.).
Evolution du Recrutement de la Civelle (Anguilla anguilla) dans l'estuaire de la Loire, France, de 1977 à 1988. The Evolution of Recruitment of Glass Eel (Anguilla anguilla) in the Loire Estuary, France, from 1977 to 1988
Authors: Guerault D. , Desaunay Y.
Published: February 2007

Two series of indices, based on glass‐eel fisheries data, are used: From 1977 onwards, average catch shows a decreasing trend, becoming moderate after 1982. Fisheries indicators (CPUE, fishing effort and total yield), estimated since 1985, demonstrate contrasting evolutions inside the Loire fishery, according to location (upstream/downstream zone) and to climate. The coastal recruitment of glass‐eel is likely to be less biased by catchability variation.
The Growth of Eels: A Critical Assessment of Data from Open Waters
Authors: Berg R.
Published: February 2007

In the literature, annual growth data of eels between about 3 cm and 25 cm are reported. The high growth values were often especially taken as average for the growth of populations in open waters. A critical assessment of data in the literature shows that the average annual growth in different regions of Europe is between about 3 cm and 6 cm and does not exceed 10 cm.
Distribution du peuplement d'anguilles à l'échelle régionale Bretagne et Basse Normandie (France). Distribution of Eel at a Regional Scale, Brittany and Lower Normandy (France)
Authors: Legault A. , Porcher J. P.
Published: February 2007

The cartography of eel population in Brittany and Lower Normandy shows that the fitting out of rivers may be considered as the essential degradation factor of eel distribution. The setting up of not passable dams and the multiplication of partially passable dams also reduces eel stocks of numerous rivers. The improvement of eel migratory paths should be constituted a priority of protection and restoration of the natural stock.
Les passes à anguilles en Europe. Eel ladder devices in Europe
Authors: Legault A. , Fontenelle G. , Gascuel D. , Rigaud C.
Published: February 2007

After a study trip through seven european countries, a synthesis about 24 eel ladder devices was written as a special report. A detailed description and the role of these fish facilities are discussed. In spite of very simple design principles and after experiments on a French river, efficiency tests are recommended.
Growth and Reproductive Responses of Daphnia to Cyanobacterial Blooms on the Potomac River
Authors: Fulton Rolland S. , Jones R. Christian
Published: February 2007

We examined reproductive responses of the cladoceran Daphnia parvula to algal assemblages from the Potomac River, during and after Cyanobacterial blooms. Algal assemblages were manipulated by filtration, dilution, or additions of nutritious algae, in order to determine causes for growth inhibition. There was no evidence for lethal toxic effects or food limitation of population growth rates during the algal bloom, although growth was food limited later in the year. However, growth rates were lower in the experiment conducted during the Cyanobacteria bloom than in later experiments, and the results suggest an inhibitory factor associated with the particulate material. Results from filtered treatments indicate that picoplankton present in hypereutrophic waters can support Daphnia growth and reproduction.
The Influence of Toxic and Filamentous Blue‐green Algae on Feeding and Population Growth of the Rotifer Brachionus rubens
Authors: Rothhaupt Karl Otto
Published: February 2007

The effect of toxic and of filamentous blue‐green algae on feeding and population growth of the rotifer Brachionus rubens was investigated in laboratory experiments. A toxic strain of Microcystis aeruginosa was ingested, but rotifers cultured with Microcystis died faster than nonfed controls. The rigid filaments of Cylindrospermopsis raciborskii were not ingested, reduced the ingestion of simultaneously offered algae, and depressed population growth rates. The soft filaments of Anabaena flos‐aquae were ingested at a moderate rate, did not reduce ingestion of other algae, and were used as an additional food in population growth experiments.
Development, Growth and Survivorship of Juvenile Calanoid Copepods on Diets of Cyanobacteria and Algae
Authors: Xu Zhenkang , Burns Carolyn W.
Published: February 2007

Nauplii and immature copepodites of Boeckella triarticulata, B. hamata and B. dilatata were tested for their ability to survive and grow on monospecific diets of four species of filamentous cyanobacteria, Cyclotella (Cy) and Cryptomonas (Cr) at 2 mg dry weight 1−1. Cr supported the development from nauplius to adult of all three calanoid species; complete development on other diets occurred only in B. dilatata on Cy and Anabaena oscillarioides (Ao). Differences between nauplii and copepodites of B. dilatata and B. hamata in survivorship and development on diets of Cy, Anabaena flos‐aquae (Af), Ao and Nostoc sp. 2 (N2) imply ontogenetic shifts in resource utilization with developmental phase. Ranked in order of their ability to support the development of juvenile boeckellids the foods were Cr > Cy > Ao > N2 > Af > Nostoc calcicola = no food.
Studies of Aquatic Fungi. XVIII. Aquatic Fungi in Lake S̀niardwy and Eighteen Neighbouring Lakes
Authors: Czeczuga Bazyli
Published: February 2007

The work was undertaken to investigate the mycoflora of Lake S̀niardwy and eighteen adjacent lakes.

Samples of water were collected once a month (1984‐1987) for hydrochemical analysis and studies of the fungi content.

Forty species of fungi were found in lake S̀niardwy and 60 in other lakes. The following fungi unknown from Poland were found in these lakes: Olpidium endogenum, Olpidium granulatum, Dictyomorpha dioica, Phlyctochytrium aureliae, Rhizophydium planktonicum, Zygorhizidium melosirae, Cladochytrium polystomum, Blastocladia rostrata, Olpidiopsis achlyae, Olpidiopsis pythii, Lagenidium rabenhorstii, Pythiella vernalis, Achlya rodrigueziana, Anguillospora gigantea, Dimorphospora foliicola and Mycocentrospora aquatica.
Fish in Reservoirs
Authors: Fernando C. H. , Holčík Juraj
Published: February 2007

In all reservoirs the fish fauna is recruited from their riverine antecedents. The nature of the riverine environment, created by its unstable hydrological regime, favours the evolution of generalist species. Of these species, only a few are preadapted to lacustrine conditions. When riverine fish communities are trapped in a reservoir, most of the fish stay close to the shore, the mouth of tributaries and in shallows. The pelagic and deep waters are poorly utilized and the yield of fish is below the natural productivity of these water bodies, especially in the case of deep and large reservoirs. This occurs unless the dammed river contains fish species from families which are preadapted for lacustrine conditions. A positive correlation between the percentage of pelagic fish and the total yield of fish in reservoirs indicates that the pelagial represents a vacant habitat, only seldom invaded by riverine species. This situation probably applies to the deep water of reservoirs too, although sufficient data to demonstrate this are not available. The littoral region of reservoirs is utilized by some generalists of euryoecious species derived from the indigenous riverine fauna which may be preadapted for lacustrine conditions. If such preadapted lacustrine species are not present, the introduction of lacustrine species or those preadapted for the lacustrine environment is desirable under certain circumstances. However, caution must be exercised in any introduction.
A Study of Phytoplankton in the Adriatic Sea after the July 1984 Bloom
Authors: Viličió Damir
Published: February 2007

Distribution of nano‐ and microphytoplankton cell density and biomass (expressed as biovolume) were analyzed at 64 stations in the Adriatic Sea, in July 1984, after the northern Adriatic bloom. Biomass distribution may be indirectly linked with the position of eutrophication sources and currents. „Macroaggregates”︁ formed after the bloom are descriptively analysed.
The Distribution and Origins of Freshwater Fishes in the Balkan Peninsula, Especially in Greece
Authors: Economidis Panos S. , Banarescu Petru M.
Published: February 2007

Zoogeography of freshwater fish fauna of the Balkan peninsula south of the Danube has been studied. Four main divisions ‐ Ponto‐Aegean, Attiko‐Beotia, Dalmatia and South Adriatic‐Ionian ‐ were recognized. All endemics belong to European, Euro‐Siberian or Palaearctic taxa, originated from ancestors of the Euro‐Siberian stock and reached the area as well as Asia Minor in Oligocene or Miocene. Central European and Danubian species are intruders of late Pliocene to Pleistocene arriving by the freshened Black Sea and its drainage basin or directly from the North (Middle Danube) by river captures.
Trend Analysis of Biological Parameters in the Baltic (1976‐1988)
Authors: Schulz Sigurd , Kaiser Wolfgang , Breuel Günther
Published: February 2007

Eutrophication of the nature is one of the most relevant problems for the human society today. In comparison to terrestrial and limnological ecosystems, however, the marine environment is affected with some exceptions of coastal waters in a minor degree. On the basis of data from 1976–1988 trend analysis for chlorophyll, primary production, zooplankton biomass and water transparency have been carried out for the Mecklenburg Bight and different areas of the Baltic proper.

As expected from the longterm increase in the nutrient levels, also for some pelagic biological variables increasing trends could be observed. At least for chlorophyll they are significant in the 95% probability level for all investigated areas. Primary production shows also an increase, however, not significant for each subarea. For zooplankton nearly no changes could be observed. All data reflect a high interannual variability, which can partly be explained by meteorological and oceanological conditions. The results are discussed from an ecological point of view. The increase in phytoplankton variables is considered to be at least partly related to the eutrophication of the Baltic.
Influence of Eutrophication on the Distribution of Phytobenthic Plant and Animal Communities
Authors: Kautsky Hans
Published: February 2007

A short review of effects of eutrophication on the phytobenthic communities in the Baltic Sea is given. Future monitoring aspects are briefly discussed. Local changes in phytobenthic communities outside point sources (e.g. industry outlets, enclosed bays receiving effluents from land runoff etc.) are easily detected and can be due to nutrient enrichment and/or toxic substances. In recent decades, changes have been reported from apparently unaffected areas. The disappearance of Fucus vesiculosus is the most conspicuous. The cause of events is similar in those areas: increases in epiphytes give increases in grazer populations. The thallus of algae is heavily grazed upon. The epiphytes shade their host and filamentous algae compete for space, disturbing recruitment and leading to a decrease in diversity. The rapid response of opportunistic filamentous algae on nutrient enrichment and changing herbivore pressure can easily be observed. Therefore, repeated surveillance in defined areas, which integrates the environmental response in both animal and plant communities, may be a fruitful approach for detecting large scale eutrophication of the Baltic Sea.
Eutrophication and Restoration Measures in the Darß‐Zingst Bodden Chain
Authors: Nausch Günther , Schlungbaum Günter
Published: February 2007

The Darß‐Zingst Bodden chain, part of the brackish inner coastal waters of Mecklenburg‐Vorpommern, Germany, is supplied by large amounts of phosphorus and nitrogen from the catchment area. Due to the shallowness an additional nutrient input is realized via sediment‐water interactions. The results are highly eutrophicated water bodies. But in contrast to other systems the actual nutrient concentrations are mainly influenced by hydrographical features and don't reflect the loading situation. Possible rehabilitation methods are discussed for the Bodden chain handling, especially the sediment problem.